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</script><div class='container-fluid mb-1'><a name='top'></a><div class='row'><div class='col'><a class='dotted' data-bs-toggle='collapse' data-bs-target='#collapseIndex' aria-expanded='false' aria-controls='collapseIndex'>¬</a><a class='dotted' href='#c++'>c++</a><a class='dotted' href='#python'>python</a><a class='dotted' href='#assembly'>assembly</a><a class='dotted' href='#verilog'>verilog</a><a class='dotted' href='#c'>c</a><a class='float-right' href='https://github.com/mxsjoberg/code'>Github</a></div></div><div class='row'><div class='col' style='column-count:4;'><div class='collapse' id='collapseIndex'><div class='row'><hr class='muted'></div>c++<a class='dotted' style='margin-left:12px;' href='#c++-misc'>misc</a><br><a class='dotted' href='#bubble-sort-cpp'>bubble-sort.cpp</a><br><a class='dotted' href='#math-cpp'>math.cpp</a><br><a class='dotted' href='#multithreading-cpp'>multithreading.cpp</a><br><a class='dotted' href='#namespace-cpp'>namespace.cpp</a><br><a class='dotted' href='#signals-cpp'>signals.cpp</a><br><a class='dotted' href='#smart-pointers-cpp'>smart-pointers.cpp</a><br><a class='dotted' href='#vectors-cpp'>vectors.cpp</a><br><br><div class='row'><hr class='muted'></div>c++<a class='dotted' style='margin-left:12px;' href='#c++-algos'>algos</a><br><a class='dotted' href='#binary-search-cpp'>binary-search.cpp</a><br><a class='dotted' href='#find-adjacent-cpp'>find-adjacent.cpp</a><br><a class='dotted' href='#for-each-cpp'>for-each.cpp</a><br><br><div class='row'><hr class='muted'></div>python<a class='dotted' style='margin-left:12px;' href='#python-misc'>misc</a><br><a class='dotted' href='#alu-in-python-py'>alu-in-python.py</a><br><a class='dotted' href='#bubble-sort-py'>bubble-sort.py</a><br><a class='dotted' href='#combinations-with-replacement-py'>combinations-with-replacement.py</a><br><a class='dotted' href='#composing-functions-py'>composing-functions.py</a><br><a class='dotted' href='#enumerate-py'>enumerate.py</a><br><a class='dotted' 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href='#widrow-hoff-learning-algorithm-py'>widrow-hoff-learning-algorithm.py</a><br><br><div class='row'><hr class='muted'></div>python<a class='dotted' style='margin-left:12px;' href='#python-euler'>euler</a><br><a class='dotted' href='##1-multiples-of-3-and-5-py'>#1-multiples-of-3-and-5.py</a><br><a class='dotted' href='##2-even-fibonacci-numbers-py'>#2-even-fibonacci-numbers.py</a><br><a class='dotted' href='##3-largest-prime-factor-py'>#3-largest-prime-factor.py</a><br><a class='dotted' href='##4-largest-palindrome-product-py'>#4-largest-palindrome-product.py</a><br><a class='dotted' href='##5-smallest-multiple-py'>#5-smallest-multiple.py</a><br><a class='dotted' href='##6-sum-square-difference-py'>#6-sum-square-difference.py</a><br><a class='dotted' href='##7-10001st-prime-py'>#7-10001st-prime.py</a><br><a class='dotted' href='##8-largest-product-in-a-series-py'>#8-largest-product-in-a-series.py</a><br><a class='dotted' href='##9-special-pythagorean-triplet-py'>#9-special-pythagorean-triplet.py</a><br><a class='dotted' href='##10-summation-of-primes-py'>#10-summation-of-primes.py</a><br><a class='dotted' href='##11-largest-product-in-grid-py'>#11-largest-product-in-grid.py</a><br><a class='dotted' href='##12-highly-divisible-triangular-number-py'>#12-highly-divisible-triangular-number.py</a><br><a class='dotted' href='##13-large-sum-py'>#13-large-sum.py</a><br><a class='dotted' href='##14-longest-collatz-sequence-py'>#14-longest-collatz-sequence.py</a><br><a class='dotted' href='##15-lattice-paths-py'>#15-lattice-paths.py</a><br><a class='dotted' href='##16-power-digit-sum-py'>#16-power-digit-sum.py</a><br><a class='dotted' href='##17-number-letter-counts-py'>#17-number-letter-counts.py</a><br><br><div class='row'><hr class='muted'></div>python<a class='dotted' style='margin-left:12px;' href='#python-compilers'>compilers</a><br><a class='dotted' href='#ast-constant-folding-py'>ast-constant-folding.py</a><br><a class='dotted' href='#ast-to-tac-to-llvm-py'>ast-to-tac-to-llvm.py</a><br><a class='dotted' href='#dsl-in-python-py'>dsl-in-python.py</a><br><a class='dotted' href='#for-loop-implementation-py'>for-loop-implementation.py</a><br><a class='dotted' href='#loop-tiling-optimization-py'>loop-tiling-optimization.py</a><br><a class='dotted' href='#opencl-in-python-py'>opencl-in-python.py</a><br><a class='dotted' href='#operator-fusion-on-parse-tree-py'>operator-fusion-on-parse-tree.py</a><br><a class='dotted' href='#parallelization-optimization-py'>parallelization-optimization.py</a><br><a class='dotted' href='#shunting-yard-algorithm-py'>shunting-yard-algorithm.py</a><br><a class='dotted' href='#tokenizer-using-generator-in-python-py'>tokenizer-using-generator-in-python.py</a><br><a class='dotted' href='#vectorization-optimization-py'>vectorization-optimization.py</a><br><br><div class='row'><hr class='muted'></div>assembly<a class='dotted' style='margin-left:12px;' href='#assembly-x86'>x86</a><br><a class='dotted' href='#hello-x86-asm'>hello-x86.asm</a><br><br><div class='row'><hr class='muted'></div>verilog<a class='dotted' style='margin-left:12px;' href='#verilog-misc'>misc</a><br><a class='dotted' href='#intro-v'>intro.v</a><br><br><div class='row'><hr class='muted'></div>verilog<a class='dotted' style='margin-left:12px;' href='#verilog-gates'>gates</a><br><a class='dotted' href='#and16-v'>and16.v</a><br><a class='dotted' href='#and-v'>and.v</a><br><a class='dotted' href='#dmux4way-v'>dmux4way.v</a><br><a class='dotted' href='#dmux8way-v'>dmux8way.v</a><br><a class='dotted' href='#dmux-v'>dmux.v</a><br><a class='dotted' href='#mux4way16-v'>mux4way16.v</a><br><a class='dotted' href='#mux8way16-v'>mux8way16.v</a><br><a class='dotted' href='#mux16-v'>mux16.v</a><br><a class='dotted' href='#mux-v'>mux.v</a><br><a class='dotted' href='#nand-v'>nand.v</a><br><a class='dotted' href='#not16-v'>not16.v</a><br><a class='dotted' href='#not-v'>not.v</a><br><a class='dotted' href='#or8way-v'>or8way.v</a><br><a class='dotted' href='#or16-v'>or16.v</a><br><a class='dotted' href='#or-v'>or.v</a><br><a class='dotted' href='#xor-v'>xor.v</a><br><br><div class='row'><hr class='muted'></div>c<a class='dotted' style='margin-left:12px;' href='#c-misc'>misc</a><br><a class='dotted' href='#goto_in_c-c'>goto_in_c.c</a><br><a class='dotted' href='#header-files-c'>header-files.c</a><br><a class='dotted' href='#linked-list-c'>linked-list.c</a><br><a class='dotted' href='#macros-c'>macros.c</a><br><a class='dotted' href='#memory-c'>memory.c</a><br><a class='dotted' href='#pointers-c'>pointers.c</a><br><a class='dotted' href='#valist-c'>valist.c</a><br><br></div></div></div><div class='row'><hr></div><div class='row'><div class='col-12'><a name='c++'></a><h1>c++<a class='dotted' href='#c++-misc'>misc</a><a class='dotted' href='#c++-algos'>algos</a><a class='dotted float-right' href='#top'>^</a></h1><a name='c++-misc'></a><h2>misc<a class='dotted float-right' href='#top'>^</a></h2><p><a class='dotted' href='#bubble-sort-cpp'>bubble-sort.cpp</a><a class='dotted' href='#math-cpp'>math.cpp</a><a class='dotted' href='#multithreading-cpp'>multithreading.cpp</a><a class='dotted' href='#namespace-cpp'>namespace.cpp</a><a class='dotted' href='#signals-cpp'>signals.cpp</a><a class='dotted' href='#smart-pointers-cpp'>smart-pointers.cpp</a><a class='dotted' href='#vectors-cpp'>vectors.cpp</a></p><div class='container-fluid p-0'><div class='row wrapper'><div class='col-12 box'><a class='dotted' href='#bubble-sort-cpp'>bubble-sort.cpp</a>[<a href='https://github.com/mxsjoberg/code/blob/master/c++/misc/bubble-sort.cpp' name='bubble-sort-cpp' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="cp">#include</span><span class="w"> </span><span class="cpf"><iostream></span><span class="cp"></span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><vector></span><span class="cp"></span>
<span class="k">constexpr</span><span class="w"> </span><span class="kt">void</span><span class="w"> </span><span class="nf">print_elements_in_vector</span><span class="p">(</span><span class="n">std</span><span class="o">::</span><span class="n">vector</span><span class="o"><</span><span class="kt">int</span><span class="o">></span><span class="w"> </span><span class="n">numbers</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">number</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="n">numbers</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">number</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
<span class="kt">int</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">vector</span><span class="o"><</span><span class="kt">int</span><span class="o">></span><span class="w"> </span><span class="n">numbers</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="mi">14</span><span class="p">,</span><span class="w"> </span><span class="mi">33</span><span class="p">,</span><span class="w"> </span><span class="mi">27</span><span class="p">,</span><span class="w"> </span><span class="mi">35</span><span class="p">,</span><span class="w"> </span><span class="mi">10</span><span class="w"> </span><span class="p">};</span><span class="w"></span>
<span class="w"> </span><span class="c1">// print unsorted</span>
<span class="w"> </span><span class="n">print_elements_in_vector</span><span class="p">(</span><span class="n">numbers</span><span class="p">);</span><span class="w"> </span><span class="c1">// 14 33 27 35 10</span>
<span class="w"> </span><span class="c1">// bubble sort</span>
<span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o"><</span><span class="w"> </span><span class="n">numbers</span><span class="p">.</span><span class="n">size</span><span class="p">();</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">j</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="n">j</span><span class="w"> </span><span class="o"><</span><span class="w"> </span><span class="n">numbers</span><span class="p">.</span><span class="n">size</span><span class="p">()</span><span class="w"> </span><span class="o">-</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span><span class="w"> </span><span class="n">j</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">numbers</span><span class="p">[</span><span class="n">j</span><span class="p">]</span><span class="w"> </span><span class="o">></span><span class="w"> </span><span class="n">numbers</span><span class="p">[</span><span class="n">j</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="mi">1</span><span class="p">])</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">temp</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">numbers</span><span class="p">[</span><span class="n">j</span><span class="p">];</span><span class="w"></span>
<span class="w"> </span><span class="c1">// swap positions</span>
<span class="w"> </span><span class="n">numbers</span><span class="p">[</span><span class="n">j</span><span class="p">]</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">numbers</span><span class="p">[</span><span class="n">j</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="mi">1</span><span class="p">];</span><span class="w"></span>
<span class="w"> </span><span class="n">numbers</span><span class="p">[</span><span class="n">j</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="mi">1</span><span class="p">]</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">temp</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="w"> </span><span class="c1">// print sorted</span>
<span class="w"> </span><span class="n">print_elements_in_vector</span><span class="p">(</span><span class="n">numbers</span><span class="p">);</span><span class="w"> </span><span class="c1">// 10 14 27 33 35</span>
<span class="p">}</span><span class="w"></span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#math-cpp'>math.cpp</a>[<a href='https://github.com/mxsjoberg/code/blob/master/c++/misc/math.cpp' name='math-cpp' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="cp">#include</span><span class="w"> </span><span class="cpf"><iostream></span><span class="cp"></span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><cmath></span><span class="cp"></span>
<span class="kt">int</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">INFINITY</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// inf</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">NAN</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// nan</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">isgreater</span><span class="p">(</span><span class="mi">42</span><span class="p">,</span><span class="w"> </span><span class="mi">10</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 1</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">isless</span><span class="p">(</span><span class="mi">42</span><span class="p">,</span><span class="w"> </span><span class="mi">10</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 0</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">isnan</span><span class="p">(</span><span class="n">NAN</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 1</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">isinf</span><span class="p">(</span><span class="n">INFINITY</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 1</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">isfinite</span><span class="p">(</span><span class="mi">42</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 1</span>
<span class="w"> </span><span class="c1">// trigonometric</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">cos</span><span class="p">(</span><span class="mi">42</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// -0.399985</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">sin</span><span class="p">(</span><span class="mi">42</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// -0.916522</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">tan</span><span class="p">(</span><span class="mi">42</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 2.29139</span>
<span class="w"> </span><span class="c1">// exponential and logarithmic</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">log10</span><span class="p">(</span><span class="mi">10</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 1</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">log2</span><span class="p">(</span><span class="mi">8</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 3</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">exp</span><span class="p">(</span><span class="mi">2</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 7.38906</span>
<span class="w"> </span><span class="c1">// binary exponential function</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">exp2</span><span class="p">(</span><span class="mi">2</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 4</span>
<span class="w"> </span><span class="c1">// natural logarithm</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">log</span><span class="p">(</span><span class="mi">10</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 2.30259</span>
<span class="w"> </span><span class="c1">// power and root</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">pow</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 8</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">sqrt</span><span class="p">(</span><span class="mi">16</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 4</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">cbrt</span><span class="p">(</span><span class="mi">27</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 3</span>
<span class="w"> </span><span class="c1">// rounding and remainder</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">ceil</span><span class="p">(</span><span class="mf">41.5</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 42</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">floor</span><span class="p">(</span><span class="mf">42.5</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 42</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">trunc</span><span class="p">(</span><span class="mf">42.5</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 42</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">round</span><span class="p">(</span><span class="mf">41.5</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 42</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">remainder</span><span class="p">(</span><span class="mi">142</span><span class="p">,</span><span class="w"> </span><span class="mi">100</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 42</span>
<span class="w"> </span><span class="c1">// round to nearest integer</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">rint</span><span class="p">(</span><span class="mf">42.5</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 42</span>
<span class="w"> </span><span class="c1">// round to nearby integer</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">nearbyint</span><span class="p">(</span><span class="mf">42.5</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 42</span>
<span class="w"> </span><span class="c1">// manipulation</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">copysign</span><span class="p">(</span><span class="mi">42</span><span class="p">,</span><span class="w"> </span><span class="mi">-1</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// -42</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">nan</span><span class="p">(</span><span class="s">"42"</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// nan</span>
<span class="w"> </span><span class="c1">// minimum, maximum, difference</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">fdim</span><span class="p">(</span><span class="mi">52</span><span class="p">,</span><span class="w"> </span><span class="mi">10</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 42</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">fmax</span><span class="p">(</span><span class="mi">42</span><span class="p">,</span><span class="w"> </span><span class="mi">10</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 42</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">fmin</span><span class="p">(</span><span class="mi">42</span><span class="p">,</span><span class="w"> </span><span class="mi">10</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 10</span>
<span class="w"> </span><span class="c1">// absolute value (can handle floating-point)</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">fabs</span><span class="p">(</span><span class="mf">-12.5</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 12.5</span>
<span class="w"> </span><span class="c1">// absolute value (only for integers)</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">abs</span><span class="p">(</span><span class="mi">-42</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 42</span>
<span class="w"> </span><span class="c1">// fused multiply-add</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">fma</span><span class="p">(</span><span class="mf">42.5</span><span class="p">,</span><span class="w"> </span><span class="mi">10</span><span class="p">,</span><span class="w"> </span><span class="mi">200</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 625</span>
<span class="p">}</span><span class="w"></span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#multithreading-cpp'>multithreading.cpp</a>[<a href='https://github.com/mxsjoberg/code/blob/master/c++/misc/multithreading.cpp' name='multithreading-cpp' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="cp">#include</span><span class="w"> </span><span class="cpf"><iostream></span><span class="cp"></span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><pthread.h></span><span class="cp"></span>
<span class="k">constexpr</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">max_threads</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">5</span><span class="p">;</span><span class="w"></span>
<span class="kt">void</span><span class="w"> </span><span class="o">*</span><span class="nf">print</span><span class="p">(</span><span class="kt">void</span><span class="w"> </span><span class="o">*</span><span class="n">thread_id</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="kt">long</span><span class="w"> </span><span class="n">tid</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">(</span><span class="kt">long</span><span class="p">)</span><span class="w"> </span><span class="n">thread_id</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"thread_id: "</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">tid</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="c1">// terminate</span>
<span class="w"> </span><span class="n">pthread_exit</span><span class="p">(</span><span class="nb">NULL</span><span class="p">);</span><span class="w"></span>
<span class="p">};</span><span class="w"></span>
<span class="kt">int</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">pthread_t</span><span class="w"> </span><span class="n">threads</span><span class="p">[</span><span class="n">max_threads</span><span class="p">];</span><span class="w"></span>
<span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="kr">thread</span><span class="p">[</span><span class="n">max_threads</span><span class="p">];</span><span class="w"></span>
<span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o"><</span><span class="w"> </span><span class="n">max_threads</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="kr">thread</span><span class="p">[</span><span class="n">i</span><span class="p">]</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">i</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"creating thread:"</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="kr">thread</span><span class="p">[</span><span class="n">i</span><span class="p">]</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="c1">// create thread using pthread_create(thread, attr, start_routine, arg)</span>
<span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">pthread_create</span><span class="p">(</span><span class="o">&</span><span class="n">threads</span><span class="p">[</span><span class="n">i</span><span class="p">],</span><span class="w"> </span><span class="nb">NULL</span><span class="p">,</span><span class="w"> </span><span class="n">print</span><span class="p">,</span><span class="w"> </span><span class="p">(</span><span class="kt">void</span><span class="o">*</span><span class="p">)</span><span class="w"> </span><span class="o">&</span><span class="kr">thread</span><span class="p">[</span><span class="n">i</span><span class="p">])</span><span class="w"> </span><span class="o">!=</span><span class="w"> </span><span class="mi">0</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"unable to create thread: "</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="kr">thread</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="c1">// fail</span>
<span class="w"> </span><span class="n">exit</span><span class="p">(</span><span class="mi">-1</span><span class="p">);</span><span class="w"></span>
<span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="w"> </span><span class="c1">// terminate</span>
<span class="w"> </span><span class="n">pthread_exit</span><span class="p">(</span><span class="nb">NULL</span><span class="p">);</span><span class="w"></span>
<span class="w"> </span><span class="c1">// creating thread:0</span>
<span class="w"> </span><span class="c1">// creating thread:1</span>
<span class="w"> </span><span class="c1">// thread_id: 140701949382784</span>
<span class="w"> </span><span class="c1">// thread_id: 140701949382788</span>
<span class="w"> </span><span class="c1">// creating thread:2</span>
<span class="w"> </span><span class="c1">// creating thread:3</span>
<span class="w"> </span><span class="c1">// thread_id: 140701949382792</span>
<span class="w"> </span><span class="c1">// creating thread:4</span>
<span class="w"> </span><span class="c1">// thread_id: 140701949382796</span>
<span class="w"> </span><span class="c1">// thread_id: 140701949382800</span>
<span class="p">}</span><span class="w"></span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#namespace-cpp'>namespace.cpp</a>[<a href='https://github.com/mxsjoberg/code/blob/master/c++/misc/namespace.cpp' name='namespace-cpp' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="cp">#include</span><span class="w"> </span><span class="cpf"><iostream></span><span class="cp"></span>
<span class="c1">// define namespace</span>
<span class="k">namespace</span><span class="w"> </span><span class="nn">my_functions</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="kt">void</span><span class="w"> </span><span class="nf">function</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"called: my_functions::function"</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
<span class="kt">int</span><span class="w"> </span><span class="n">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">my_functions</span><span class="o">::</span><span class="n">function</span><span class="p">();</span><span class="w"> </span><span class="c1">// called: my_functions::function</span>
<span class="p">}</span><span class="w"></span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#signals-cpp'>signals.cpp</a>[<a href='https://github.com/mxsjoberg/code/blob/master/c++/misc/signals.cpp' name='signals-cpp' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="cp">#include</span><span class="w"> </span><span class="cpf"><iostream></span><span class="cp"></span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><csignal></span><span class="cp"></span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><unistd.h></span><span class="cp"></span>
<span class="c1">// signal handler</span>
<span class="kt">void</span><span class="w"> </span><span class="nf">terminate</span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">sig</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"</span><span class="se">\n</span><span class="s">signal: "</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">sig</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="n">exit</span><span class="p">(</span><span class="n">sig</span><span class="p">);</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
<span class="kt">int</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="c1">// register signal</span>
<span class="w"> </span><span class="n">signal</span><span class="p">(</span><span class="n">SIGINT</span><span class="p">,</span><span class="w"> </span><span class="n">terminate</span><span class="p">);</span><span class="w"> </span>
<span class="w"> </span><span class="c1">// keyboard interrupt</span>
<span class="w"> </span><span class="k">while</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"stuck doing something really hard... (press ^C to exit)"</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="n">sleep</span><span class="p">(</span><span class="mi">5</span><span class="p">);</span><span class="w"></span>
<span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="w"> </span><span class="c1">// stuck doing something really hard... (press ^C to exit)</span>
<span class="w"> </span><span class="c1">// ^C</span>
<span class="w"> </span><span class="c1">// signal: 2</span>
<span class="p">}</span><span class="w"></span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#smart-pointers-cpp'>smart-pointers.cpp</a>[<a href='https://github.com/mxsjoberg/code/blob/master/c++/misc/smart-pointers.cpp' name='smart-pointers-cpp' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="c1">// smart pointers handle allocation and deletion of memory</span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><memory></span><span class="cp"></span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><iostream></span><span class="cp"></span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><vector></span><span class="cp"></span>
<span class="k">class</span><span class="w"> </span><span class="nc">MyClass</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">unique_ptr</span><span class="o"><</span><span class="n">std</span><span class="o">::</span><span class="n">vector</span><span class="o"><</span><span class="kt">int</span><span class="o">>></span><span class="w"> </span><span class="n">data</span><span class="p">;</span><span class="w"> </span><span class="c1">// unique_ptr is a smart pointer</span>
<span class="k">public</span><span class="o">:</span><span class="w"></span>
<span class="w"> </span><span class="n">MyClass</span><span class="p">(</span><span class="k">const</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">size</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="n">data</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">make_unique</span><span class="o"><</span><span class="n">std</span><span class="o">::</span><span class="n">vector</span><span class="o"><</span><span class="kt">int</span><span class="o">>></span><span class="p">(</span><span class="n">size</span><span class="p">);</span><span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="c1">// allocate memory with make_unique</span>
<span class="w"> </span><span class="kt">void</span><span class="w"> </span><span class="n">print_data</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="k">auto</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="o">*</span><span class="n">data</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="p">};</span><span class="w"></span>
<span class="kt">void</span><span class="w"> </span><span class="nf">function_using_data</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">MyClass</span><span class="w"> </span><span class="n">my_class</span><span class="p">(</span><span class="mi">5</span><span class="p">);</span><span class="w"> </span><span class="c1">// lifetime tied to scope</span>
<span class="w"> </span><span class="n">my_class</span><span class="p">.</span><span class="n">print_data</span><span class="p">();</span><span class="w"></span>
<span class="p">}</span><span class="w"> </span><span class="c1">// my_class is destroyed here</span>
<span class="kt">int</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">function_using_data</span><span class="p">();</span><span class="w"> </span><span class="c1">// 0 0 0 0 0</span>
<span class="p">}</span><span class="w"></span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#vectors-cpp'>vectors.cpp</a>[<a href='https://github.com/mxsjoberg/code/blob/master/c++/misc/vectors.cpp' name='vectors-cpp' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="cp">#include</span><span class="w"> </span><span class="cpf"><iostream></span><span class="cp"></span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><vector></span><span class="cp"></span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><string></span><span class="cp"></span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><format></span><span class="cp"></span>
<span class="kt">int</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="c1">// vector of ints</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">vector</span><span class="o"><</span><span class="kt">int</span><span class="o">></span><span class="w"> </span><span class="n">numbers</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="c1">// size</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">numbers</span><span class="p">.</span><span class="n">size</span><span class="p">()</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 0</span>
<span class="w"> </span><span class="c1">// push values</span>
<span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o"><=</span><span class="w"> </span><span class="mi">5</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">numbers</span><span class="p">.</span><span class="n">push_back</span><span class="p">(</span><span class="n">i</span><span class="p">);</span><span class="w"></span>
<span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">numbers</span><span class="p">.</span><span class="n">size</span><span class="p">()</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 5</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">numbers</span><span class="p">[</span><span class="mi">3</span><span class="p">]</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// 4</span>
<span class="w"> </span><span class="c1">// vector of strings</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">vector</span><span class="o"><</span><span class="n">std</span><span class="o">::</span><span class="n">string</span><span class="o">></span><span class="w"> </span><span class="n">strings</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="s">"c++"</span><span class="w"> </span><span class="p">};</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">strings</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">" "</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">strings</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"> </span><span class="c1">// hello c++</span>
<span class="p">}</span><span class="w"></span>
</pre></div>
</div></div></div><a name='c++-algos'></a><h2>algos<a class='dotted float-right' href='#top'>^</a></h2><p><a class='dotted' href='#binary-search-cpp'>binary-search.cpp</a><a class='dotted' href='#find-adjacent-cpp'>find-adjacent.cpp</a><a class='dotted' href='#for-each-cpp'>for-each.cpp</a></p><div class='container-fluid p-0'><div class='row wrapper'><div class='col-12 box'><a class='dotted' href='#binary-search-cpp'>binary-search.cpp</a>[<a href='https://github.com/mxsjoberg/code/blob/master/c++/algos/binary-search.cpp' name='binary-search-cpp' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="cp">#include</span><span class="w"> </span><span class="cpf"><algorithm></span><span class="cp"></span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><vector></span><span class="cp"></span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><iostream></span><span class="cp"></span>
<span class="kt">int</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">vector</span><span class="o"><</span><span class="kt">int</span><span class="o">></span><span class="w"> </span><span class="n">numbers</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="mi">4</span><span class="p">,</span><span class="w"> </span><span class="mi">5</span><span class="w"> </span><span class="p">};</span><span class="w"></span>
<span class="w"> </span><span class="c1">// binary_search</span>
<span class="w"> </span><span class="kt">bool</span><span class="w"> </span><span class="n">found</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">binary_search</span><span class="p">(</span><span class="n">numbers</span><span class="p">.</span><span class="n">begin</span><span class="p">(),</span><span class="w"> </span><span class="n">numbers</span><span class="p">.</span><span class="n">end</span><span class="p">(),</span><span class="w"> </span><span class="mi">4</span><span class="p">);</span><span class="w"></span>
<span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">found</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"found value"</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">else</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"not found"</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="w"> </span><span class="c1">// found value</span>
<span class="p">}</span><span class="w"></span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#find-adjacent-cpp'>find-adjacent.cpp</a>[<a href='https://github.com/mxsjoberg/code/blob/master/c++/algos/find-adjacent.cpp' name='find-adjacent-cpp' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="cp">#include</span><span class="w"> </span><span class="cpf"><algorithm></span><span class="cp"></span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><vector></span><span class="cp"></span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><iostream></span><span class="cp"></span>
<span class="kt">bool</span><span class="w"> </span><span class="nf">twice</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">a</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">b</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">a</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="mi">2</span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="n">b</span><span class="p">;</span><span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="kt">int</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">vector</span><span class="o"><</span><span class="kt">int</span><span class="o">></span><span class="w"> </span><span class="n">numbers</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="mi">50</span><span class="p">,</span><span class="w"> </span><span class="mi">40</span><span class="p">,</span><span class="w"> </span><span class="mi">10</span><span class="p">,</span><span class="w"> </span><span class="mi">20</span><span class="p">,</span><span class="w"> </span><span class="mi">20</span><span class="w"> </span><span class="p">};</span><span class="w"></span>
<span class="w"> </span><span class="c1">// adjacent_find</span>
<span class="w"> </span><span class="k">auto</span><span class="w"> </span><span class="n">iter</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">adjacent_find</span><span class="p">(</span><span class="n">numbers</span><span class="p">.</span><span class="n">begin</span><span class="p">(),</span><span class="w"> </span><span class="n">numbers</span><span class="p">.</span><span class="n">end</span><span class="p">(),</span><span class="w"> </span><span class="n">twice</span><span class="p">);</span><span class="w"></span>
<span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">iter</span><span class="w"> </span><span class="o">!=</span><span class="w"> </span><span class="n">numbers</span><span class="p">.</span><span class="n">end</span><span class="p">())</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="o">*</span><span class="n">iter</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">", "</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="o">*</span><span class="p">(</span><span class="n">iter</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="mi">1</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">else</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"no adjacent pairs"</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="w"> </span><span class="c1">// 10, 20</span>
<span class="p">}</span><span class="w"></span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#for-each-cpp'>for-each.cpp</a>[<a href='https://github.com/mxsjoberg/code/blob/master/c++/algos/for-each.cpp' name='for-each-cpp' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="cp">#include</span><span class="w"> </span><span class="cpf"><algorithm></span><span class="cp"></span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><vector></span><span class="cp"></span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><iostream></span><span class="cp"></span>
<span class="kt">int</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">vector</span><span class="o"><</span><span class="kt">int</span><span class="o">></span><span class="w"> </span><span class="n">numbers</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="mi">4</span><span class="p">,</span><span class="w"> </span><span class="mi">5</span><span class="w"> </span><span class="p">};</span><span class="w"></span>
<span class="w"> </span><span class="c1">// multiply each element in numbers using for_each</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">for_each</span><span class="p">(</span><span class="n">numbers</span><span class="p">.</span><span class="n">begin</span><span class="p">(),</span><span class="w"> </span><span class="n">numbers</span><span class="p">.</span><span class="n">end</span><span class="p">(),</span><span class="w"> </span><span class="p">[](</span><span class="kt">int</span><span class="w"> </span><span class="o">&</span><span class="n">number</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">number</span><span class="w"> </span><span class="o">*=</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="p">});</span><span class="w"></span>
<span class="w"> </span><span class="c1">// for_each</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">for_each</span><span class="p">(</span><span class="n">numbers</span><span class="p">.</span><span class="n">begin</span><span class="p">(),</span><span class="w"> </span><span class="n">numbers</span><span class="p">.</span><span class="n">end</span><span class="p">(),</span><span class="w"> </span><span class="p">[](</span><span class="kt">int</span><span class="w"> </span><span class="n">number</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">number</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">endl</span><span class="p">;</span><span class="w"></span>
<span class="w"> </span><span class="p">});</span><span class="w"></span>
<span class="w"> </span><span class="c1">// 2 4 6 8 10</span>
<span class="p">}</span><span class="w"></span>
</pre></div>
</div></div></div></div></div><div class='row'><hr></div><div class='row'><div class='col-12'><a name='python'></a><h1>python<a class='dotted' href='#python-misc'>misc</a><a class='dotted' href='#python-ci'>ci</a><a class='dotted' href='#python-ml'>ml</a><a class='dotted' href='#python-euler'>euler</a><a class='dotted' href='#python-compilers'>compilers</a><a class='dotted float-right' href='#top'>^</a></h1><a name='python-misc'></a><h2>misc<a class='dotted float-right' href='#top'>^</a></h2><p><a class='dotted' href='#alu-in-python-py'>alu-in-python.py</a><a class='dotted' href='#bubble-sort-py'>bubble-sort.py</a><a class='dotted' href='#combinations-with-replacement-py'>combinations-with-replacement.py</a><a class='dotted' href='#composing-functions-py'>composing-functions.py</a><a class='dotted' href='#enumerate-py'>enumerate.py</a><a class='dotted' href='#erlang-b-formula-py'>erlang-b-formula.py</a><a class='dotted' href='#foreign-function-library-py'>foreign-function-library.py</a><a class='dotted' href='#function-wrappers-py'>function-wrappers.py</a><a class='dotted' href='#functools-cache-py'>functools-cache.py</a><a class='dotted' href='#glide-typing-problem-py'>glide-typing-problem.py</a><a class='dotted' href='#linked-list-using-recordclass-py'>linked-list-using-recordclass.py</a><a class='dotted' href='#numpy-operators-py'>numpy-operators.py</a><a class='dotted' href='#pandas-operators-py'>pandas-operators.py</a><a class='dotted' href='#partial-functions-py'>partial-functions.py</a><a class='dotted' href='#regular-expression-py'>regular-expression.py</a><a class='dotted' href='#sobel-filter-using-opencl-py'>sobel-filter-using-opencl.py</a></p><div class='container-fluid p-0'><div class='row wrapper'><div class='col-12 box'><a class='dotted' href='#alu-in-python-py'>alu-in-python.py</a>[<a href='https://github.com/mxsjoberg/code/blob/master/python/misc/alu-in-python.py' name='alu-in-python-py' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="sd">"""</span>
<span class="sd">An ALU is a combinational logic circuit that performs</span>
<span class="sd">arithmetic and bitwise operations on input bits. This</span>
<span class="sd">is a 16-bit implementation.</span>
<span class="sd">"""</span>
<span class="c1"># binary to signed decimal</span>
<span class="k">def</span> <span class="nf">binary_to_signed</span><span class="p">(</span><span class="n">lst</span><span class="p">):</span>
<span class="n">binary_str</span> <span class="o">=</span> <span class="s1">''</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="nb">map</span><span class="p">(</span><span class="nb">str</span><span class="p">,</span> <span class="n">lst</span><span class="p">))</span>
<span class="k">if</span> <span class="p">(</span><span class="n">binary_str</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">==</span> <span class="s1">'1'</span><span class="p">):</span>
<span class="c1"># invert bits</span>
<span class="n">inverted_str</span> <span class="o">=</span> <span class="s1">''</span><span class="o">.</span><span class="n">join</span><span class="p">([</span><span class="s1">'1'</span> <span class="k">if</span> <span class="n">c</span> <span class="o">==</span> <span class="s1">'0'</span> <span class="k">else</span> <span class="s1">'0'</span> <span class="k">for</span> <span class="n">c</span> <span class="ow">in</span> <span class="n">binary_str</span><span class="p">[</span><span class="mi">1</span><span class="p">:]])</span>
<span class="n">decimal</span> <span class="o">=</span> <span class="o">-</span><span class="nb">int</span><span class="p">(</span><span class="n">inverted_str</span><span class="p">,</span> <span class="mi">2</span><span class="p">)</span> <span class="o">-</span> <span class="mi">1</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">decimal</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="n">binary_str</span><span class="p">,</span> <span class="mi">2</span><span class="p">)</span>
<span class="k">return</span> <span class="n">decimal</span>
<span class="k">assert</span> <span class="n">binary_to_signed</span><span class="p">([</span><span class="mi">1</span><span class="p">,</span><span class="mi">1</span><span class="p">,</span><span class="mi">1</span><span class="p">,</span><span class="mi">1</span><span class="p">,</span><span class="mi">1</span><span class="p">,</span><span class="mi">1</span><span class="p">,</span><span class="mi">1</span><span class="p">,</span><span class="mi">1</span><span class="p">])</span> <span class="o">==</span> <span class="o">-</span><span class="mi">1</span>
<span class="c1"># https://en.wikipedia.org/wiki/Two%27s_complement</span>
<span class="k">def</span> <span class="nf">twos_complement_addition</span><span class="p">(</span><span class="n">a</span><span class="p">,</span> <span class="n">b</span><span class="p">):</span>
<span class="c1"># convert to binary strings</span>
<span class="n">a_bin</span> <span class="o">=</span> <span class="s1">''</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="nb">map</span><span class="p">(</span><span class="nb">str</span><span class="p">,</span> <span class="n">a</span><span class="p">))</span>
<span class="n">b_bin</span> <span class="o">=</span> <span class="s1">''</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="nb">map</span><span class="p">(</span><span class="nb">str</span><span class="p">,</span> <span class="n">b</span><span class="p">))</span>
<span class="c1"># number of bits</span>
<span class="n">bits</span> <span class="o">=</span> <span class="nb">max</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">a_bin</span><span class="p">),</span> <span class="nb">len</span><span class="p">(</span><span class="n">b_bin</span><span class="p">))</span>
<span class="c1"># convert to twos complement</span>
<span class="n">a_twos</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="n">a_bin</span><span class="p">,</span> <span class="mi">2</span><span class="p">)</span>
<span class="n">b_twos</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="n">b_bin</span><span class="p">,</span> <span class="mi">2</span><span class="p">)</span>
<span class="c1"># addition</span>
<span class="n">result_twos</span> <span class="o">=</span> <span class="n">a_twos</span> <span class="o">+</span> <span class="n">b_twos</span>
<span class="c1"># convert result to binary string</span>
<span class="n">result</span> <span class="o">=</span> <span class="nb">bin</span><span class="p">(</span><span class="n">result_twos</span> <span class="o">&</span> <span class="p">(</span><span class="mi">2</span> <span class="o">**</span> <span class="n">bits</span> <span class="o">-</span> <span class="mi">1</span><span class="p">))[</span><span class="mi">2</span><span class="p">:]</span>
<span class="c1"># convert result to list of ints</span>
<span class="n">result</span> <span class="o">=</span> <span class="nb">list</span><span class="p">(</span><span class="nb">map</span><span class="p">(</span><span class="nb">int</span><span class="p">,</span> <span class="n">result</span><span class="p">))</span>
<span class="c1"># padding (if needed)</span>
<span class="k">if</span> <span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">result</span><span class="p">)</span> <span class="o"><</span> <span class="n">bits</span><span class="p">):</span>
<span class="c1"># insert 0s to front</span>
<span class="k">for</span> <span class="n">bit</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">bits</span> <span class="o">-</span> <span class="nb">len</span><span class="p">(</span><span class="n">result</span><span class="p">)):</span> <span class="n">result</span><span class="o">.</span><span class="n">insert</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="mi">0</span><span class="p">)</span>
<span class="k">return</span> <span class="nb">list</span><span class="p">(</span><span class="nb">map</span><span class="p">(</span><span class="nb">int</span><span class="p">,</span> <span class="n">result</span><span class="p">))</span>
<span class="k">assert</span> <span class="n">twos_complement_addition</span><span class="p">([</span><span class="mi">0</span><span class="p">,</span><span class="mi">1</span><span class="p">,</span><span class="mi">0</span><span class="p">,</span><span class="mi">1</span><span class="p">],</span> <span class="p">[</span><span class="mi">0</span><span class="p">,</span><span class="mi">1</span><span class="p">,</span><span class="mi">0</span><span class="p">,</span><span class="mi">1</span><span class="p">])</span> <span class="o">==</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span><span class="mi">0</span><span class="p">,</span><span class="mi">1</span><span class="p">,</span><span class="mi">0</span><span class="p">]</span>
<span class="sd">"""</span>
<span class="sd">if (zx == 1) set x = 0 : 16-bit</span>
<span class="sd">if (nx == 1) set x = ~x : 16-bit bitwise not</span>
<span class="sd">if (zy == 1) set y = 0 : 16-bit constant</span>
<span class="sd">if (ny == 1) set y = ~y : 16-bit bitwise not</span>
<span class="sd">if (f == 1) set out = x + y : 16-bit twos complement addition</span>
<span class="sd">if (f == 0) set out = x & y : 16-bit bitwise and</span>
<span class="sd">if (no == 1) set out = ~out : 16-bit bitwise not</span>
<span class="sd">if (out == 0) set zr = 1 : 1-bit</span>
<span class="sd">if (out < 0) set ng = 1 : 1-bit</span>
<span class="sd">"""</span>
<span class="k">def</span> <span class="nf">ALU</span><span class="p">(</span><span class="n">x</span><span class="p">,</span> <span class="n">y</span><span class="p">,</span> <span class="n">zx</span><span class="o">=</span><span class="mi">0</span><span class="p">,</span> <span class="n">nx</span><span class="o">=</span><span class="mi">0</span><span class="p">,</span> <span class="n">zy</span><span class="o">=</span><span class="mi">0</span><span class="p">,</span> <span class="n">ny</span><span class="o">=</span><span class="mi">0</span><span class="p">,</span> <span class="n">f</span><span class="o">=</span><span class="mi">0</span><span class="p">,</span> <span class="n">no</span><span class="o">=</span><span class="mi">0</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> x : input x : 16-bit</span>
<span class="sd"> y : input y : 16-bit</span>
<span class="sd"> zx : zero x : 1-bit</span>
<span class="sd"> nx : negate x : 1-bit</span>
<span class="sd"> zy : zero y : 1-bit</span>
<span class="sd"> ny : negate y : 1-bit</span>
<span class="sd"> f : function : 1-bit</span>
<span class="sd"> no : negate out : 1-bit</span>
<span class="sd"> """</span>
<span class="c1"># init output</span>
<span class="n">out</span> <span class="o">=</span> <span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">*</span> <span class="nb">len</span><span class="p">(</span><span class="n">x</span><span class="p">)</span>
<span class="n">zr</span><span class="o">=</span><span class="mi">0</span>
<span class="n">ng</span><span class="o">=</span><span class="mi">0</span>
<span class="c1"># if (zx == 1) set x = 0</span>
<span class="k">if</span> <span class="n">zx</span> <span class="o">==</span> <span class="mi">1</span><span class="p">:</span>
<span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">x</span><span class="p">)):</span>
<span class="n">x</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">=</span> <span class="mi">0</span>
<span class="c1"># if (nx == 1) set x = ~x</span>
<span class="k">if</span> <span class="n">nx</span> <span class="o">==</span> <span class="mi">1</span><span class="p">:</span>
<span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">x</span><span class="p">)):</span>
<span class="k">if</span> <span class="n">x</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">==</span> <span class="mi">1</span><span class="p">:</span> <span class="n">x</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">=</span> <span class="mi">0</span>
<span class="k">else</span><span class="p">:</span> <span class="n">x</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">=</span> <span class="mi">1</span>
<span class="c1"># if (zy == 1) set y = 0</span>
<span class="k">if</span> <span class="n">zy</span> <span class="o">==</span> <span class="mi">1</span><span class="p">:</span>
<span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">y</span><span class="p">)):</span>
<span class="n">y</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">=</span> <span class="mi">0</span>
<span class="c1"># if (ny == 1) set y = ~y</span>
<span class="k">if</span> <span class="n">ny</span> <span class="o">==</span> <span class="mi">1</span><span class="p">:</span>
<span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">y</span><span class="p">)):</span>
<span class="k">if</span> <span class="n">y</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">==</span> <span class="mi">1</span><span class="p">:</span> <span class="n">y</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">=</span> <span class="mi">0</span>
<span class="k">else</span><span class="p">:</span> <span class="n">y</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">=</span> <span class="mi">1</span>
<span class="c1"># if (f == 1) set out = x + y</span>
<span class="k">if</span> <span class="n">f</span> <span class="o">==</span> <span class="mi">1</span><span class="p">:</span> <span class="n">out</span> <span class="o">=</span> <span class="n">twos_complement_addition</span><span class="p">(</span><span class="n">x</span><span class="p">,</span> <span class="n">y</span><span class="p">)</span>
<span class="c1"># if (f == 0) set out = x & y</span>
<span class="k">if</span> <span class="n">f</span> <span class="o">==</span> <span class="mi">0</span><span class="p">:</span>
<span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">x</span><span class="p">)):</span>
<span class="k">if</span> <span class="n">x</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="ow">and</span> <span class="n">y</span><span class="p">[</span><span class="n">i</span><span class="p">]:</span> <span class="n">out</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">=</span> <span class="mi">1</span>
<span class="k">else</span><span class="p">:</span> <span class="n">out</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">=</span> <span class="mi">0</span>
<span class="c1"># if (no == 1) set out = ~out</span>
<span class="k">if</span> <span class="n">no</span> <span class="o">==</span> <span class="mi">1</span><span class="p">:</span>
<span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">out</span><span class="p">)):</span>
<span class="k">if</span> <span class="n">out</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">==</span> <span class="mi">1</span><span class="p">:</span> <span class="n">out</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">=</span> <span class="mi">0</span>
<span class="k">else</span><span class="p">:</span> <span class="n">out</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">=</span> <span class="mi">1</span>
<span class="c1"># if (out == 0) set zr = 1</span>
<span class="k">if</span> <span class="nb">all</span><span class="p">(</span><span class="n">bit</span> <span class="o">==</span> <span class="mi">0</span> <span class="k">for</span> <span class="n">bit</span> <span class="ow">in</span> <span class="n">out</span><span class="p">):</span> <span class="n">zr</span> <span class="o">=</span> <span class="mi">1</span>
<span class="c1"># if (out < 0) set ng = 1</span>
<span class="k">if</span> <span class="n">binary_to_signed</span><span class="p">(</span><span class="n">out</span><span class="p">)</span> <span class="o"><</span> <span class="mi">0</span><span class="p">:</span> <span class="n">ng</span> <span class="o">=</span> <span class="mi">1</span>
<span class="k">return</span> <span class="n">out</span><span class="p">,</span> <span class="n">zr</span><span class="p">,</span> <span class="n">ng</span>
<span class="c1"># test cases</span>
<span class="sd">"""</span>
<span class="sd">| x | y |zx|nx|zy|ny|f|no| out |zr|ng|</span>
<span class="sd">|0000000000000000|1111111111111111| 1| 0| 1| 0|1| 0|0000000000000000| 1| 0|</span>
<span class="sd">|0000000000000000|1111111111111111| 1| 1| 1| 1|1| 1|0000000000000001| 0| 0|</span>
<span class="sd">|0000000000000000|1111111111111111| 1| 1| 1| 0|1| 0|1111111111111111| 0| 1|</span>
<span class="sd">|0000000000000000|1111111111111111| 0| 0| 1| 1|0| 0|0000000000000000| 1| 0|</span>
<span class="sd">|0000000000000000|1111111111111111| 1| 1| 0| 0|0| 0|1111111111111111| 0| 1|</span>
<span class="sd">|0000000000000000|1111111111111111| 0| 0| 1| 1|0| 1|1111111111111111| 0| 1|</span>
<span class="sd">|0000000000000000|1111111111111111| 1| 1| 0| 0|0| 1|0000000000000000| 1| 0|</span>
<span class="sd">|0000000000000000|1111111111111111| 0| 0| 1| 1|1| 1|0000000000000000| 1| 0|</span>
<span class="sd">|0000000000000000|1111111111111111| 1| 1| 0| 0|1| 1|0000000000000001| 0| 0|</span>
<span class="sd">|0000000000000000|1111111111111111| 0| 1| 1| 1|1| 1|0000000000000001| 0| 0|</span>
<span class="sd">|0000000000000000|1111111111111111| 1| 1| 0| 1|1| 1|0000000000000000| 1| 0|</span>
<span class="sd">|0000000000000000|1111111111111111| 0| 0| 1| 1|1| 0|1111111111111111| 0| 1|</span>
<span class="sd">|0000000000000000|1111111111111111| 1| 1| 0| 0|1| 0|1111111111111110| 0| 1|</span>
<span class="sd">|0000000000000000|1111111111111111| 0| 0| 0| 0|1| 0|1111111111111111| 0| 1|</span>
<span class="sd">|0000000000000000|1111111111111111| 0| 1| 0| 0|1| 1|0000000000000001| 0| 0|</span>
<span class="sd">|0000000000000000|1111111111111111| 0| 0| 0| 1|1| 1|1111111111111111| 0| 1|</span>
<span class="sd">|0000000000000000|1111111111111111| 0| 0| 0| 0|0| 0|0000000000000000| 1| 0|</span>
<span class="sd">|0000000000000000|1111111111111111| 0| 1| 0| 1|0| 1|1111111111111111| 0| 1|</span>
<span class="sd">|0000000000010001|0000000000000011| 1| 0| 1| 0|1| 0|0000000000000000| 1| 0|</span>
<span class="sd">|0000000000010001|0000000000000011| 1| 1| 1| 1|1| 1|0000000000000001| 0| 0|</span>
<span class="sd">|0000000000010001|0000000000000011| 1| 1| 1| 0|1| 0|1111111111111111| 0| 1|</span>
<span class="sd">|0000000000010001|0000000000000011| 0| 0| 1| 1|0| 0|0000000000010001| 0| 0|</span>
<span class="sd">|0000000000010001|0000000000000011| 1| 1| 0| 0|0| 0|0000000000000011| 0| 0|</span>
<span class="sd">|0000000000010001|0000000000000011| 0| 0| 1| 1|0| 1|1111111111101110| 0| 1|</span>
<span class="sd">|0000000000010001|0000000000000011| 1| 1| 0| 0|0| 1|1111111111111100| 0| 1|</span>
<span class="sd">|0000000000010001|0000000000000011| 0| 0| 1| 1|1| 1|1111111111101111| 0| 1|</span>
<span class="sd">|0000000000010001|0000000000000011| 1| 1| 0| 0|1| 1|1111111111111101| 0| 1|</span>
<span class="sd">|0000000000010001|0000000000000011| 0| 1| 1| 1|1| 1|0000000000010010| 0| 0|</span>
<span class="sd">|0000000000010001|0000000000000011| 1| 1| 0| 1|1| 1|0000000000000100| 0| 0|</span>
<span class="sd">|0000000000010001|0000000000000011| 0| 0| 1| 1|1| 0|0000000000010000| 0| 0|</span>
<span class="sd">|0000000000010001|0000000000000011| 1| 1| 0| 0|1| 0|0000000000000010| 0| 0|</span>
<span class="sd">|0000000000010001|0000000000000011| 0| 0| 0| 0|1| 0|0000000000010100| 0| 0|</span>
<span class="sd">|0000000000010001|0000000000000011| 0| 1| 0| 0|1| 1|0000000000001110| 0| 0|</span>
<span class="sd">|0000000000010001|0000000000000011| 0| 0| 0| 1|1| 1|1111111111110010| 0| 1|</span>
<span class="sd">|0000000000010001|0000000000000011| 0| 0| 0| 0|0| 0|0000000000000001| 0| 0|</span>
<span class="sd">|0000000000010001|0000000000000011| 0| 1| 0| 1|0| 1|0000000000010011| 0| 0|</span>
<span class="sd">"""</span>
<span class="k">with</span> <span class="nb">open</span><span class="p">(</span><span class="s2">"_alu_tests.txt"</span><span class="p">,</span> <span class="s2">"r"</span><span class="p">)</span> <span class="k">as</span> <span class="n">tests</span><span class="p">:</span>
<span class="k">for</span> <span class="n">test</span> <span class="ow">in</span> <span class="n">tests</span><span class="o">.</span><span class="n">read</span><span class="p">()</span><span class="o">.</span><span class="n">split</span><span class="p">(</span><span class="s1">'</span><span class="se">\n</span><span class="s1">'</span><span class="p">)[</span><span class="mi">1</span><span class="p">:]:</span>
<span class="n">test</span> <span class="o">=</span> <span class="n">test</span><span class="o">.</span><span class="n">split</span><span class="p">(</span><span class="s1">'|'</span><span class="p">)[</span><span class="mi">1</span><span class="p">:</span><span class="o">-</span><span class="mi">1</span><span class="p">]</span>
<span class="n">values</span> <span class="o">=</span> <span class="p">[</span><span class="n">col</span><span class="o">.</span><span class="n">strip</span><span class="p">()</span> <span class="k">for</span> <span class="n">col</span> <span class="ow">in</span> <span class="n">test</span><span class="p">]</span>
<span class="n">out</span><span class="p">,</span> <span class="n">zr</span><span class="p">,</span> <span class="n">ng</span> <span class="o">=</span> <span class="n">ALU</span><span class="p">(</span>
<span class="c1"># input x</span>
<span class="nb">list</span><span class="p">(</span><span class="nb">map</span><span class="p">(</span><span class="nb">int</span><span class="p">,</span> <span class="nb">list</span><span class="p">(</span><span class="n">values</span><span class="p">[</span><span class="mi">0</span><span class="p">]))),</span>
<span class="c1"># input y</span>
<span class="nb">list</span><span class="p">(</span><span class="nb">map</span><span class="p">(</span><span class="nb">int</span><span class="p">,</span> <span class="nb">list</span><span class="p">(</span><span class="n">values</span><span class="p">[</span><span class="mi">1</span><span class="p">]))),</span>
<span class="c1"># control bits</span>
<span class="n">zx</span><span class="o">=</span><span class="nb">int</span><span class="p">(</span><span class="n">values</span><span class="p">[</span><span class="mi">2</span><span class="p">]),</span>
<span class="n">nx</span><span class="o">=</span><span class="nb">int</span><span class="p">(</span><span class="n">values</span><span class="p">[</span><span class="mi">3</span><span class="p">]),</span>
<span class="n">zy</span><span class="o">=</span><span class="nb">int</span><span class="p">(</span><span class="n">values</span><span class="p">[</span><span class="mi">4</span><span class="p">]),</span>
<span class="n">ny</span><span class="o">=</span><span class="nb">int</span><span class="p">(</span><span class="n">values</span><span class="p">[</span><span class="mi">5</span><span class="p">]),</span>
<span class="n">f</span><span class="o">=</span><span class="nb">int</span><span class="p">(</span><span class="n">values</span><span class="p">[</span><span class="mi">6</span><span class="p">]),</span>
<span class="n">no</span><span class="o">=</span><span class="nb">int</span><span class="p">(</span><span class="n">values</span><span class="p">[</span><span class="mi">7</span><span class="p">])</span>
<span class="p">)</span>
<span class="k">assert</span> <span class="n">out</span> <span class="o">==</span> <span class="nb">list</span><span class="p">(</span><span class="nb">map</span><span class="p">(</span><span class="nb">int</span><span class="p">,</span> <span class="nb">list</span><span class="p">(</span><span class="n">values</span><span class="p">[</span><span class="mi">8</span><span class="p">])))</span>
<span class="k">assert</span> <span class="n">zr</span> <span class="o">==</span> <span class="nb">int</span><span class="p">(</span><span class="n">values</span><span class="p">[</span><span class="mi">9</span><span class="p">])</span>
<span class="k">assert</span> <span class="n">ng</span> <span class="o">==</span> <span class="nb">int</span><span class="p">(</span><span class="n">values</span><span class="p">[</span><span class="mi">10</span><span class="p">])</span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#bubble-sort-py'>bubble-sort.py</a>[<a href='https://github.com/mxsjoberg/code/blob/master/python/misc/bubble-sort.py' name='bubble-sort-py' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="c1"># https://en.wikipedia.org/wiki/Bubble_sort</span>
<span class="n">unsorted_list</span> <span class="o">=</span> <span class="p">[</span><span class="mi">14</span><span class="p">,</span> <span class="mi">33</span><span class="p">,</span> <span class="mi">27</span><span class="p">,</span> <span class="mi">35</span><span class="p">,</span> <span class="mi">10</span><span class="p">]</span>
<span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">unsorted_list</span><span class="p">)):</span>
<span class="k">for</span> <span class="n">j</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">unsorted_list</span><span class="p">)</span> <span class="o">-</span> <span class="mi">1</span><span class="p">):</span>
<span class="k">if</span> <span class="n">unsorted_list</span><span class="p">[</span><span class="n">j</span><span class="p">]</span> <span class="o">></span> <span class="n">unsorted_list</span><span class="p">[</span><span class="n">j</span> <span class="o">+</span> <span class="mi">1</span><span class="p">]:</span>
<span class="n">temp</span> <span class="o">=</span> <span class="n">unsorted_list</span><span class="p">[</span><span class="n">j</span><span class="p">]</span>
<span class="c1"># swap</span>
<span class="n">unsorted_list</span><span class="p">[</span><span class="n">j</span><span class="p">]</span> <span class="o">=</span> <span class="n">unsorted_list</span><span class="p">[</span><span class="n">j</span> <span class="o">+</span> <span class="mi">1</span><span class="p">]</span>
<span class="n">unsorted_list</span><span class="p">[</span><span class="n">j</span> <span class="o">+</span> <span class="mi">1</span><span class="p">]</span> <span class="o">=</span> <span class="n">temp</span>
<span class="nb">print</span><span class="p">(</span><span class="n">unsorted_list</span><span class="p">)</span> <span class="c1"># [10, 14, 27, 33, 35]</span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#combinations-with-replacement-py'>combinations-with-replacement.py</a>[<a href='https://github.com/mxsjoberg/code/blob/master/python/misc/combinations-with-replacement.py' name='combinations-with-replacement-py' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">itertools</span> <span class="kn">import</span> <span class="n">combinations_with_replacement</span>
<span class="n">my_list</span> <span class="o">=</span> <span class="p">[</span><span class="s1">'A'</span><span class="p">,</span> <span class="s1">'B'</span><span class="p">]</span>
<span class="n">combinations</span> <span class="o">=</span> <span class="p">[]</span>
<span class="k">for</span> <span class="n">item</span> <span class="ow">in</span> <span class="nb">list</span><span class="p">(</span><span class="nb">range</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">my_list</span><span class="p">))):</span>
<span class="n">combinations</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="nb">list</span><span class="p">(</span><span class="n">combinations_with_replacement</span><span class="p">(</span><span class="n">my_list</span><span class="p">,</span> <span class="n">item</span> <span class="o">+</span> <span class="mi">1</span><span class="p">)))</span>
<span class="nb">print</span><span class="p">(</span><span class="n">combinations</span><span class="p">)</span>
<span class="c1"># [[('A',), ('B',)], [('A', 'A'), ('A', 'B'), ('B', 'B')]]</span>
<span class="c1"># flatten</span>
<span class="n">combinations</span> <span class="o">=</span> <span class="p">[</span><span class="n">a</span> <span class="k">for</span> <span class="n">b</span> <span class="ow">in</span> <span class="n">combinations</span> <span class="k">for</span> <span class="n">a</span> <span class="ow">in</span> <span class="n">b</span><span class="p">]</span>
<span class="nb">print</span><span class="p">(</span><span class="n">combinations</span><span class="p">)</span>
<span class="c1"># [('A',), ('B',), ('A', 'A'), ('A', 'B'), ('B', 'B')]</span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#composing-functions-py'>composing-functions.py</a>[<a href='https://github.com/mxsjoberg/code/blob/master/python/misc/composing-functions.py' name='composing-functions-py' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">functools</span>
<span class="kn">import</span> <span class="nn">operator</span>
<span class="k">def</span> <span class="nf">compose</span><span class="p">(</span><span class="n">a</span><span class="p">,</span> <span class="n">b</span><span class="p">):</span> <span class="k">return</span> <span class="k">lambda</span> <span class="n">x</span><span class="p">:</span> <span class="n">a</span><span class="p">(</span><span class="n">b</span><span class="p">(</span><span class="n">x</span><span class="p">))</span>
<span class="k">def</span> <span class="nf">square</span><span class="p">(</span><span class="n">x</span><span class="p">):</span> <span class="k">return</span> <span class="n">x</span> <span class="o">*</span> <span class="n">x</span>
<span class="k">def</span> <span class="nf">double</span><span class="p">(</span><span class="n">x</span><span class="p">):</span> <span class="k">return</span> <span class="n">x</span> <span class="o">*</span> <span class="mi">2</span>
<span class="c1"># double then square</span>
<span class="n">op</span> <span class="o">=</span> <span class="n">compose</span><span class="p">(</span><span class="n">square</span><span class="p">,</span> <span class="n">double</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="n">op</span><span class="p">(</span><span class="mi">5</span><span class="p">))</span> <span class="c1"># 100</span>
<span class="c1"># passing operator as argument</span>
<span class="n">numbers</span> <span class="o">=</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">,</span> <span class="mi">4</span><span class="p">,</span> <span class="mi">5</span><span class="p">]</span>
<span class="nb">print</span><span class="p">(</span><span class="n">functools</span><span class="o">.</span><span class="n">reduce</span><span class="p">(</span><span class="n">operator</span><span class="o">.</span><span class="n">add</span><span class="p">,</span> <span class="n">numbers</span><span class="p">))</span> <span class="c1"># 15</span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#enumerate-py'>enumerate.py</a>[<a href='https://github.com/mxsjoberg/code/blob/master/python/misc/enumerate.py' name='enumerate-py' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="n">my_list</span> <span class="o">=</span> <span class="p">[</span><span class="s2">"Zero"</span><span class="p">,</span> <span class="s2">"One"</span><span class="p">,</span> <span class="s2">"Two"</span><span class="p">,</span> <span class="s2">"Three"</span><span class="p">,</span> <span class="s2">"Four"</span><span class="p">,</span> <span class="s2">"Five"</span><span class="p">]</span>
<span class="k">for</span> <span class="n">item</span> <span class="ow">in</span> <span class="nb">enumerate</span><span class="p">(</span><span class="n">my_list</span><span class="p">):</span> <span class="nb">print</span><span class="p">(</span><span class="n">item</span><span class="p">)</span>
<span class="c1"># (0, 'First')</span>
<span class="c1"># (1, 'Second')</span>
<span class="c1"># (2, 'Third')</span>
<span class="c1"># (3, 'Fourth')</span>
<span class="c1"># (4, 'Fifth')</span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#erlang-b-formula-py'>erlang-b-formula.py</a>[<a href='https://github.com/mxsjoberg/code/blob/master/python/misc/erlang-b-formula.py' name='erlang-b-formula-py' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="c1"># https://en.wikipedia.org/wiki/Erlang_(unit)#Erlang_B_formula</span>
<span class="kn">from</span> <span class="nn">math</span> <span class="kn">import</span> <span class="n">factorial</span>
<span class="k">def</span> <span class="nf">erlang</span><span class="p">(</span><span class="n">A</span><span class="p">,</span> <span class="n">m</span><span class="p">):</span>
<span class="n">L</span> <span class="o">=</span> <span class="p">(</span><span class="n">A</span> <span class="o">**</span> <span class="n">m</span><span class="p">)</span> <span class="o">/</span> <span class="n">factorial</span><span class="p">(</span><span class="n">m</span><span class="p">)</span>
<span class="n">sum_</span> <span class="o">=</span> <span class="mi">0</span>
<span class="k">for</span> <span class="n">n</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">m</span> <span class="o">+</span> <span class="mi">1</span><span class="p">):</span> <span class="n">sum_</span> <span class="o">+=</span> <span class="p">(</span><span class="n">A</span> <span class="o">**</span> <span class="n">n</span><span class="p">)</span> <span class="o">/</span> <span class="n">factorial</span><span class="p">(</span><span class="n">n</span><span class="p">)</span>
<span class="k">return</span> <span class="p">(</span><span class="n">L</span> <span class="o">/</span> <span class="n">sum_</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="n">erlang</span><span class="p">(</span><span class="mi">90</span><span class="p">,</span> <span class="mi">107</span><span class="p">))</span> <span class="c1"># 0.008799105244742682</span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#foreign-function-library-py'>foreign-function-library.py</a>[<a href='https://github.com/mxsjoberg/code/blob/master/python/misc/foreign-function-library.py' name='foreign-function-library-py' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="sd">"""</span>
<span class="sd">A foreign function library is a library written in</span>
<span class="sd">languages other than the language it is being called</span>
<span class="sd">from. E.g., a Python program calling function from C</span>
<span class="sd">library.</span>
<span class="sd">"""</span>
<span class="sd">"""</span>
<span class="sd">// _square.c</span>
<span class="sd">#include <stdio.h></span>
<span class="sd">int square(int num) {</span>
<span class="sd"> return num * num;</span>
<span class="sd">}</span>
<span class="sd">// compile into shared library:</span>
<span class="sd">// $ gcc -shared -o _square.so -fPIC _square.c</span>
<span class="sd">"""</span>
<span class="kn">import</span> <span class="nn">ctypes</span>
<span class="c1"># load the shared library</span>
<span class="n">square_lib</span> <span class="o">=</span> <span class="n">ctypes</span><span class="o">.</span><span class="n">CDLL</span><span class="p">(</span><span class="s1">'./_square.so'</span><span class="p">)</span>
<span class="c1"># specify function return and argument types</span>
<span class="n">square_lib</span><span class="o">.</span><span class="n">square</span><span class="o">.</span><span class="n">restype</span> <span class="o">=</span> <span class="n">ctypes</span><span class="o">.</span><span class="n">c_int</span>
<span class="n">square_lib</span><span class="o">.</span><span class="n">square</span><span class="o">.</span><span class="n">argtypes</span> <span class="o">=</span> <span class="p">[</span><span class="n">ctypes</span><span class="o">.</span><span class="n">c_int</span><span class="p">]</span>
<span class="c1"># call the foreign function</span>
<span class="n">num</span> <span class="o">=</span> <span class="mi">5</span>
<span class="n">result</span> <span class="o">=</span> <span class="n">square_lib</span><span class="o">.</span><span class="n">square</span><span class="p">(</span><span class="n">num</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s2">"the square of </span><span class="si">{</span><span class="n">num</span><span class="si">}</span><span class="s2"> is </span><span class="si">{</span><span class="n">result</span><span class="si">}</span><span class="s2">"</span><span class="p">)</span>
<span class="c1"># the square of 5 is 25</span>
<span class="c1"># using C standard library functions</span>
<span class="c1"># https://gist.github.com/PewZ/8b473c2a6888c5c528635550d07c6186</span>
<span class="n">libc</span> <span class="o">=</span> <span class="n">ctypes</span><span class="o">.</span><span class="n">CDLL</span><span class="p">(</span><span class="s1">'libc.dylib'</span><span class="p">)</span>
<span class="n">libc</span><span class="o">.</span><span class="n">printf</span><span class="p">(</span><span class="sa">b</span><span class="s2">"hello world</span><span class="se">\n</span><span class="s2">"</span><span class="p">)</span> <span class="c1"># hello world</span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#function-wrappers-py'>function-wrappers.py</a>[<a href='https://github.com/mxsjoberg/code/blob/master/python/misc/function-wrappers.py' name='function-wrappers-py' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="sd">"""</span>
<span class="sd">Function wrappers can be used to modify behavior of function</span>
<span class="sd">or method. The wraps decorator copies over the function name,</span>
<span class="sd">docstring, and arguments list to the wrapper function. This</span>
<span class="sd">is very useful for debugging and logging.</span>
<span class="sd">"""</span>
<span class="kn">from</span> <span class="nn">functools</span> <span class="kn">import</span> <span class="n">wraps</span>
<span class="k">def</span> <span class="nf">logging</span><span class="p">(</span><span class="n">func</span><span class="p">):</span>
<span class="nd">@wraps</span><span class="p">(</span><span class="n">func</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">wrapper</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s2">"call to </span><span class="si">{</span><span class="n">func</span><span class="o">.</span><span class="vm">__name__</span><span class="si">}</span><span class="s2">, args: </span><span class="si">{</span><span class="n">args</span><span class="si">}</span><span class="s2">, kwargs: </span><span class="si">{</span><span class="n">kwargs</span><span class="si">}</span><span class="s2">"</span><span class="p">)</span>
<span class="k">return</span> <span class="n">func</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">)</span>
<span class="k">return</span> <span class="n">wrapper</span>
<span class="nd">@logging</span>
<span class="k">def</span> <span class="nf">power</span><span class="p">(</span><span class="n">base</span><span class="p">,</span> <span class="n">exp</span><span class="p">):</span> <span class="k">return</span> <span class="n">base</span> <span class="o">**</span> <span class="n">exp</span>
<span class="n">power</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">)</span> <span class="c1"># call to power, args: (2, 3), kwargs: {}</span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#functools-cache-py'>functools-cache.py</a>[<a href='https://github.com/mxsjoberg/code/blob/master/python/misc/functools-cache.py' name='functools-cache-py' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="sd">"""</span>
<span class="sd">The lru_cache decorator caches the results of a function</span>
<span class="sd">call with a given set of arguments. This is useful for</span>
<span class="sd">functions that are computationally expensive and have a</span>
<span class="sd">limited set of arguments.</span>
<span class="sd">"""</span>
<span class="kn">from</span> <span class="nn">functools</span> <span class="kn">import</span> <span class="n">lru_cache</span>
<span class="kn">import</span> <span class="nn">timeit</span>
<span class="k">def</span> <span class="nf">fib</span><span class="p">(</span><span class="n">n</span><span class="p">):</span> <span class="k">return</span> <span class="n">n</span> <span class="k">if</span> <span class="n">n</span> <span class="o"><</span> <span class="mi">2</span> <span class="k">else</span> <span class="n">fib</span><span class="p">(</span><span class="n">n</span> <span class="o">-</span> <span class="mi">1</span><span class="p">)</span> <span class="o">+</span> <span class="n">fib</span><span class="p">(</span><span class="n">n</span> <span class="o">-</span> <span class="mi">2</span><span class="p">)</span>
<span class="c1"># fibonacci with cache</span>
<span class="nd">@lru_cache</span><span class="p">(</span><span class="n">maxsize</span><span class="o">=</span><span class="mi">128</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">fib_cache</span><span class="p">(</span><span class="n">n</span><span class="p">):</span> <span class="k">return</span> <span class="n">n</span> <span class="k">if</span> <span class="n">n</span> <span class="o"><</span> <span class="mi">2</span> <span class="k">else</span> <span class="n">fib_cache</span><span class="p">(</span><span class="n">n</span> <span class="o">-</span> <span class="mi">1</span><span class="p">)</span> <span class="o">+</span> <span class="n">fib_cache</span><span class="p">(</span><span class="n">n</span> <span class="o">-</span> <span class="mi">2</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="nb">format</span><span class="p">(</span><span class="n">timeit</span><span class="o">.</span><span class="n">timeit</span><span class="p">(</span><span class="s1">'fib(30)'</span><span class="p">,</span> <span class="nb">globals</span><span class="o">=</span><span class="nb">globals</span><span class="p">(),</span> <span class="n">number</span><span class="o">=</span><span class="mi">1</span><span class="p">),</span> <span class="s1">'.17f'</span><span class="p">))</span>
<span class="c1"># 0.12468479387462139</span>
<span class="nb">print</span><span class="p">(</span><span class="nb">format</span><span class="p">(</span><span class="n">timeit</span><span class="o">.</span><span class="n">timeit</span><span class="p">(</span><span class="s1">'fib_cache(30)'</span><span class="p">,</span> <span class="nb">globals</span><span class="o">=</span><span class="nb">globals</span><span class="p">(),</span> <span class="n">number</span><span class="o">=</span><span class="mi">1</span><span class="p">),</span> <span class="s1">'.17f'</span><span class="p">))</span>
<span class="c1"># 0.00001071766018867</span>
<span class="nb">print</span><span class="p">(</span><span class="n">fib_cache</span><span class="o">.</span><span class="n">cache_info</span><span class="p">())</span>
<span class="c1"># CacheInfo(hits=28, misses=31, maxsize=128, currsize=31)</span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#glide-typing-problem-py'>glide-typing-problem.py</a>[<a href='https://github.com/mxsjoberg/code/blob/master/python/misc/glide-typing-problem.py' name='glide-typing-problem-py' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="sd">"""</span>
<span class="sd">Glide typing is the feature on mobile devices that allows</span>
<span class="sd">users to type by swiping across the keyboard. The keyboard</span>
<span class="sd">will predict the word based on the path of the swipe.</span>
<span class="sd">"""</span>
<span class="n">input_</span> <span class="o">=</span> <span class="s2">"hgferyjkllkop"</span>
<span class="n">words</span> <span class="o">=</span> <span class="p">[</span><span class="s2">"coffee"</span><span class="p">,</span> <span class="s2">"coding"</span><span class="p">,</span> <span class="s2">"happy"</span><span class="p">,</span> <span class="s2">"hello"</span><span class="p">,</span> <span class="s2">"hop"</span><span class="p">]</span>
<span class="n">chars</span> <span class="o">=</span> <span class="nb">list</span><span class="p">(</span><span class="n">input_</span><span class="p">)</span>
<span class="n">matches</span> <span class="o">=</span> <span class="p">[]</span>
<span class="k">for</span> <span class="n">word</span> <span class="ow">in</span> <span class="n">words</span><span class="p">:</span>
<span class="n">cidx</span> <span class="o">=</span> <span class="mi">0</span>
<span class="n">col</span> <span class="o">=</span> <span class="mi">0</span>
<span class="k">while</span> <span class="n">col</span> <span class="o"><</span> <span class="nb">len</span><span class="p">(</span><span class="n">chars</span><span class="p">):</span>
<span class="c1"># print(chars[col], col)</span>
<span class="k">if</span> <span class="n">chars</span><span class="p">[</span><span class="n">col</span><span class="p">]</span> <span class="o">==</span> <span class="n">word</span><span class="p">[</span><span class="n">cidx</span><span class="p">]:</span>
<span class="n">cidx</span> <span class="o">+=</span> <span class="mi">1</span>
<span class="k">if</span> <span class="n">cidx</span> <span class="o">==</span> <span class="nb">len</span><span class="p">(</span><span class="n">word</span><span class="p">):</span>
<span class="n">matches</span><span class="o">.</span><span class="n">append</span><span class="p">((</span><span class="n">word</span><span class="p">,</span> <span class="n">col</span><span class="p">))</span>
<span class="k">break</span>
<span class="n">col</span> <span class="o">+=</span> <span class="mi">1</span>
<span class="c1"># all matches</span>
<span class="nb">print</span><span class="p">(</span><span class="n">matches</span><span class="p">)</span> <span class="c1"># [('hello', 11), ('hop', 12)]</span>
<span class="c1"># first match</span>
<span class="nb">print</span><span class="p">(</span><span class="n">matches</span><span class="p">[</span><span class="mi">0</span><span class="p">][</span><span class="mi">0</span><span class="p">])</span> <span class="c1"># hello</span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#linked-list-using-recordclass-py'>linked-list-using-recordclass.py</a>[<a href='https://github.com/mxsjoberg/code/blob/master/python/misc/linked-list-using-recordclass.py' name='linked-list-using-recordclass-py' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="sd">"""</span>
<span class="sd">A linked list is a linear data structure where each element</span>
<span class="sd">is the data and reference to next element. The last element</span>
<span class="sd">reference to None and an empty linked list has a None head.</span>
<span class="sd">"""</span>
<span class="kn">from</span> <span class="nn">recordclass</span> <span class="kn">import</span> <span class="n">recordclass</span>
<span class="c1"># recordclass is a mutable namedtuple</span>
<span class="n">Element</span> <span class="o">=</span> <span class="n">recordclass</span><span class="p">(</span><span class="s2">"Element"</span><span class="p">,</span> <span class="p">[</span><span class="s2">"value"</span><span class="p">,</span> <span class="s2">"next"</span><span class="p">])</span>
<span class="k">class</span> <span class="nc">LinkedList</span><span class="p">:</span>
<span class="c1"># linked list constructor</span>
<span class="k">def</span> <span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="bp">self</span><span class="o">.</span><span class="n">head</span> <span class="o">=</span> <span class="kc">None</span>
<span class="c1"># string representation of linked list</span>
<span class="k">def</span> <span class="fm">__str__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">head</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span> <span class="k">return</span> <span class="s2">"[]"</span>
<span class="n">current</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">head</span>
<span class="n">values</span> <span class="o">=</span> <span class="p">[]</span>
<span class="k">while</span> <span class="n">current</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span>
<span class="n">values</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">current</span><span class="o">.</span><span class="n">value</span><span class="p">)</span>
<span class="n">current</span> <span class="o">=</span> <span class="n">current</span><span class="o">.</span><span class="n">next</span>
<span class="k">return</span> <span class="nb">str</span><span class="p">(</span><span class="n">values</span><span class="p">)</span>
<span class="c1"># insert element at tail</span>
<span class="k">def</span> <span class="nf">insert</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">value</span><span class="p">):</span>
<span class="c1"># insert at head</span>
<span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">head</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span> <span class="bp">self</span><span class="o">.</span><span class="n">head</span> <span class="o">=</span> <span class="n">Element</span><span class="p">(</span><span class="n">value</span><span class="p">,</span> <span class="kc">None</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">current</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">head</span>
<span class="c1"># iterate until last element</span>
<span class="k">while</span> <span class="n">current</span><span class="o">.</span><span class="n">next</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span> <span class="n">current</span> <span class="o">=</span> <span class="n">current</span><span class="o">.</span><span class="n">next</span>
<span class="c1"># insert element</span>
<span class="n">current</span><span class="o">.</span><span class="n">next</span> <span class="o">=</span> <span class="n">Element</span><span class="p">(</span><span class="n">value</span><span class="p">,</span> <span class="kc">None</span><span class="p">)</span>
<span class="c1"># remove element</span>
<span class="k">def</span> <span class="nf">remove</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">value</span><span class="p">):</span>
<span class="c1"># remove head</span>
<span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">head</span><span class="o">.</span><span class="n">value</span> <span class="o">==</span> <span class="n">value</span><span class="p">:</span> <span class="bp">self</span><span class="o">.</span><span class="n">head</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">head</span><span class="o">.</span><span class="n">next</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">current</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">head</span>
<span class="c1"># iterate until last element</span>
<span class="k">while</span> <span class="n">current</span><span class="o">.</span><span class="n">next</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span>
<span class="c1"># remove element if found</span>
<span class="k">if</span> <span class="n">current</span><span class="o">.</span><span class="n">next</span><span class="o">.</span><span class="n">value</span> <span class="o">==</span> <span class="n">value</span><span class="p">:</span>
<span class="n">current</span><span class="o">.</span><span class="n">next</span> <span class="o">=</span> <span class="n">current</span><span class="o">.</span><span class="n">next</span><span class="o">.</span><span class="n">next</span>
<span class="k">return</span>
<span class="n">current</span> <span class="o">=</span> <span class="n">current</span><span class="o">.</span><span class="n">next</span>
<span class="n">ll</span> <span class="o">=</span> <span class="n">LinkedList</span><span class="p">()</span>
<span class="n">ll</span><span class="o">.</span><span class="n">insert</span><span class="p">(</span><span class="mi">5</span><span class="p">)</span>
<span class="n">ll</span><span class="o">.</span><span class="n">insert</span><span class="p">(</span><span class="mi">10</span><span class="p">)</span>
<span class="n">ll</span><span class="o">.</span><span class="n">insert</span><span class="p">(</span><span class="mi">15</span><span class="p">)</span>
<span class="n">ll</span><span class="o">.</span><span class="n">insert</span><span class="p">(</span><span class="mi">20</span><span class="p">)</span>
<span class="n">ll</span><span class="o">.</span><span class="n">insert</span><span class="p">(</span><span class="mi">25</span><span class="p">)</span>
<span class="n">ll</span><span class="o">.</span><span class="n">insert</span><span class="p">(</span><span class="mi">30</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="n">ll</span><span class="p">)</span> <span class="c1"># [5, 10, 15, 20, 25, 30]</span>
<span class="n">ll</span><span class="o">.</span><span class="n">remove</span><span class="p">(</span><span class="mi">15</span><span class="p">)</span>
<span class="n">ll</span><span class="o">.</span><span class="n">remove</span><span class="p">(</span><span class="mi">30</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="n">ll</span><span class="p">)</span> <span class="c1"># [5, 10, 20, 25]</span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#numpy-operators-py'>numpy-operators.py</a>[<a href='https://github.com/mxsjoberg/code/blob/master/python/misc/numpy-operators.py' name='numpy-operators-py' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">numpy</span> <span class="k">as</span> <span class="nn">np</span>
<span class="c1"># numpy array basics</span>
<span class="n">a</span> <span class="o">=</span> <span class="p">[</span><span class="mi">60</span><span class="p">,</span> <span class="mi">28</span><span class="p">,</span> <span class="mi">49</span><span class="p">,</span> <span class="mi">81</span><span class="p">]</span>
<span class="n">b</span> <span class="o">=</span> <span class="p">[</span><span class="mi">55</span><span class="p">,</span> <span class="mi">634</span><span class="p">,</span> <span class="mi">704</span><span class="p">,</span> <span class="mi">2020</span><span class="p">]</span>
<span class="n">A</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">array</span><span class="p">(</span><span class="n">a</span><span class="p">,</span> <span class="n">dtype</span><span class="o">=</span><span class="s1">'i'</span><span class="p">)</span> <span class="c1"># [60 28 49 81]</span>
<span class="n">AB</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">array</span><span class="p">([</span><span class="n">a</span><span class="p">,</span> <span class="n">b</span><span class="p">])</span>
<span class="c1"># [[ 60 28 49 81]</span>
<span class="c1"># [ 55 634 704 2020]]</span>
<span class="nb">print</span><span class="p">(</span><span class="n">AB</span><span class="o">.</span><span class="n">ndim</span><span class="p">)</span> <span class="c1"># 2</span>
<span class="nb">print</span><span class="p">(</span><span class="n">AB</span><span class="o">.</span><span class="n">shape</span><span class="p">)</span> <span class="c1"># (2, 4)</span>
<span class="n">arr_zero</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">zeros</span><span class="p">(</span><span class="mi">4</span><span class="p">)</span> <span class="c1"># [0. 0. 0. 0.]</span>
<span class="n">arr_ones</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">ones</span><span class="p">((</span><span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">))</span>
<span class="c1"># [[ 1. 1. 1.]</span>
<span class="c1"># [ 1. 1. 1.]]</span>
<span class="n">arr_range</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">arange</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="mi">10</span><span class="p">)</span>
<span class="c1"># [0 1 2 3 4 5 6 7 8 9]</span>
<span class="n">arr_linspace</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">linspace</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">5</span><span class="p">)</span>
<span class="c1"># [0. 0.25 0.5 0.75 1. ]</span>
<span class="n">arr_log</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">logspace</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">5</span><span class="p">)</span>
<span class="c1"># [ 1. 1.77827941 3.16227766 5.62341325 10. ]</span>
<span class="c1"># slicing</span>
<span class="nb">print</span><span class="p">(</span><span class="n">A</span><span class="p">[</span><span class="mi">1</span><span class="p">:</span><span class="mi">3</span><span class="p">])</span>
<span class="c1"># [28 49]</span>
<span class="nb">print</span><span class="p">(</span><span class="n">AB</span><span class="p">[</span><span class="mi">0</span><span class="p">:</span><span class="mi">2</span><span class="p">,</span> <span class="mi">2</span><span class="p">:</span><span class="mi">4</span><span class="p">])</span>
<span class="c1"># [[ 49 81]</span>
<span class="c1"># [ 704 2020]]</span>
<span class="c1"># reverse order</span>
<span class="nb">print</span><span class="p">(</span><span class="n">A</span><span class="p">[::</span><span class="o">-</span><span class="mi">1</span><span class="p">])</span> <span class="c1"># [81 49 28 60]</span>
<span class="nb">print</span><span class="p">(</span><span class="n">arr_range</span><span class="o">.</span><span class="n">mean</span><span class="p">())</span> <span class="c1"># 4.5</span>
<span class="nb">print</span><span class="p">(</span><span class="n">arr_range</span><span class="o">.</span><span class="n">sum</span><span class="p">())</span> <span class="c1"># 45</span>
<span class="nb">print</span><span class="p">(</span><span class="n">AB</span><span class="o">.</span><span class="n">min</span><span class="p">())</span> <span class="c1"># 28</span>
<span class="nb">print</span><span class="p">(</span><span class="n">AB</span><span class="o">.</span><span class="n">max</span><span class="p">())</span> <span class="c1"># 2020</span>
<span class="nb">print</span><span class="p">(</span><span class="n">np</span><span class="o">.</span><span class="n">sin</span><span class="p">(</span><span class="n">AB</span><span class="p">))</span>
<span class="c1"># [[-0.30481062 0.27090579 -0.95375265 -0.62988799]</span>
<span class="c1"># [-0.99975517 -0.56605794 0.27947339 0.04406199]]</span>
<span class="nb">print</span><span class="p">(</span><span class="n">np</span><span class="o">.</span><span class="n">multiply</span><span class="p">(</span><span class="n">a</span><span class="p">,</span> <span class="n">b</span><span class="p">))</span>
<span class="c1"># [ 3300 17752 34496 163620]</span>
<span class="nb">print</span><span class="p">(</span><span class="n">np</span><span class="o">.</span><span class="n">sqrt</span><span class="p">(</span><span class="n">b</span><span class="p">))</span>
<span class="c1"># [ 7.41619849 25.17935662 26.53299832 44.94441011]</span>
<span class="c1"># min value in each column</span>
<span class="nb">print</span><span class="p">(</span><span class="n">np</span><span class="o">.</span><span class="n">minimum</span><span class="p">(</span><span class="n">a</span><span class="p">,</span> <span class="n">b</span><span class="p">))</span> <span class="c1"># [55 28 49 81]</span>
<span class="c1"># sum of axis (columns)</span>
<span class="nb">print</span><span class="p">(</span><span class="n">np</span><span class="o">.</span><span class="n">sum</span><span class="p">(</span><span class="n">AB</span><span class="p">,</span> <span class="n">axis</span><span class="o">=</span><span class="mi">1</span><span class="p">))</span> <span class="c1"># [ 218 3413]</span>
<span class="c1"># numpy indexing</span>
<span class="c1"># create array with 8 integers</span>
<span class="n">A</span> <span class="o">=</span> <span class="mi">2</span> <span class="o">*</span> <span class="n">np</span><span class="o">.</span><span class="n">arange</span><span class="p">(</span><span class="mi">8</span><span class="p">)</span><span class="o">**</span><span class="mi">2</span> <span class="o">+</span> <span class="mi">1</span>
<span class="c1"># [ 1 3 9 19 33 51 73 99]</span>
<span class="c1"># create array with 16 integers</span>
<span class="n">B</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">arange</span><span class="p">(</span><span class="mi">16</span><span class="p">)</span>
<span class="n">B</span><span class="o">.</span><span class="n">shape</span> <span class="o">=</span> <span class="p">(</span><span class="mi">4</span><span class="p">,</span> <span class="mi">4</span><span class="p">)</span>
<span class="c1"># [[ 0 1 2 3]</span>
<span class="c1"># [ 4 5 6 7]</span>
<span class="c1"># [ 8 9 10 11]</span>
<span class="c1"># [12 13 14 15]]</span>
<span class="nb">print</span><span class="p">(</span><span class="n">A</span><span class="p">[[</span><span class="mi">3</span><span class="p">,</span> <span class="o">-</span><span class="mi">1</span><span class="p">,</span> <span class="mi">1</span><span class="p">]])</span>
<span class="c1"># [19 99 3]</span>
<span class="nb">print</span><span class="p">(</span><span class="n">B</span><span class="p">[:,</span> <span class="p">[</span><span class="mi">2</span><span class="p">,</span> <span class="o">-</span><span class="mi">1</span><span class="p">,</span> <span class="mi">0</span><span class="p">]])</span>
<span class="c1"># [[ 2 3 0]</span>
<span class="c1"># [ 6 7 4]</span>
<span class="c1"># [10 11 8]</span>
<span class="c1"># [14 15 12]]</span>
<span class="c1"># elements from A at indices given by fibonacci sequence</span>
<span class="n">fibseq</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">array</span><span class="p">([</span><span class="mi">0</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">])</span>
<span class="nb">print</span><span class="p">(</span><span class="n">A</span><span class="p">[</span><span class="n">fibseq</span><span class="p">])</span> <span class="c1"># [ 1 3 3 9 19]</span>
<span class="c1"># diagonal</span>
<span class="n">i</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">arange</span><span class="p">(</span><span class="mi">4</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="n">B</span><span class="p">[</span><span class="n">i</span><span class="p">,</span> <span class="n">i</span><span class="p">])</span> <span class="c1"># [ 0 5 10 15]</span>
<span class="c1"># diagonal of part</span>
<span class="nb">print</span><span class="p">(</span><span class="n">B</span><span class="p">[</span><span class="n">i</span><span class="p">[:</span><span class="mi">3</span><span class="p">],</span> <span class="n">i</span><span class="p">[:</span><span class="mi">3</span><span class="p">]</span> <span class="o">+</span> <span class="mi">1</span><span class="p">])</span> <span class="c1"># [ 1 6 11]</span>
<span class="c1"># numpy masking</span>
<span class="c1"># create array with 16 integers</span>
<span class="n">C</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">arange</span><span class="p">(</span><span class="mi">16</span><span class="p">)</span>
<span class="n">C</span><span class="o">.</span><span class="n">shape</span> <span class="o">=</span> <span class="p">(</span><span class="mi">4</span><span class="p">,</span> <span class="mi">4</span><span class="p">)</span>
<span class="c1"># [[ 0 1 2 3]</span>
<span class="c1"># [ 4 5 6 7]</span>
<span class="c1"># [ 8 9 10 11]</span>
<span class="c1"># [12 13 14 15]]</span>
<span class="c1"># create mask with True</span>
<span class="n">mask</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">ones</span><span class="p">(</span><span class="mi">4</span><span class="p">,</span> <span class="n">dtype</span><span class="o">=</span><span class="nb">bool</span><span class="p">)</span> <span class="c1"># [ True True True True]</span>
<span class="c1"># diagonal</span>
<span class="nb">print</span><span class="p">(</span><span class="n">C</span><span class="p">[</span><span class="n">mask</span><span class="p">,</span> <span class="n">mask</span><span class="p">])</span> <span class="c1"># [ 0 5 10 15]</span>
<span class="c1"># conditional mask</span>
<span class="n">conditional</span> <span class="o">=</span> <span class="p">(</span><span class="n">C</span> <span class="o">>=</span> <span class="mi">9</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="n">C</span><span class="p">[</span><span class="n">conditional</span><span class="p">])</span> <span class="c1"># [ 9 10 11 12 13 14 15]</span>
<span class="c1"># get all values smaller than 9</span>
<span class="nb">print</span><span class="p">(</span><span class="n">C</span><span class="p">[</span><span class="n">C</span> <span class="o"><</span> <span class="mi">9</span><span class="p">])</span> <span class="c1"># [0 1 2 3 4 5 6 7 8]</span>
<span class="c1"># get all values smaller than 5 or larger than 10</span>
<span class="nb">print</span><span class="p">(</span><span class="n">C</span><span class="p">[(</span><span class="n">C</span> <span class="o"><</span> <span class="mi">5</span><span class="p">)</span> <span class="o">|</span> <span class="p">(</span><span class="n">C</span> <span class="o">></span> <span class="mi">10</span><span class="p">)])</span>
<span class="c1"># [ 0 1 2 3 4 11 12 13 14 15]</span>
<span class="c1"># where</span>
<span class="nb">print</span><span class="p">(</span><span class="n">C</span><span class="p">[</span><span class="n">np</span><span class="o">.</span><span class="n">where</span><span class="p">(</span><span class="n">C</span> <span class="o">></span> <span class="mi">10</span><span class="p">)])</span> <span class="c1"># [11 12 13 14 15]</span>
<span class="c1"># get all columns with a value less than 3</span>
<span class="nb">print</span><span class="p">(</span><span class="n">C</span><span class="p">[:,</span> <span class="n">np</span><span class="o">.</span><span class="n">where</span><span class="p">(</span><span class="n">C</span> <span class="o"><</span> <span class="mi">3</span><span class="p">)[</span><span class="mi">1</span><span class="p">]])</span>
<span class="c1"># [[ 0 1 2]</span>
<span class="c1"># [ 4 5 6]</span>
<span class="c1"># [ 8 9 10]</span>
<span class="c1"># [12 13 14]]</span>
<span class="c1"># numpy operations</span>
<span class="n">A</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">arange</span><span class="p">(</span><span class="mi">6</span><span class="p">)</span> <span class="c1"># [0 1 2 3 4 5]</span>
<span class="nb">print</span><span class="p">(</span><span class="n">A</span> <span class="o">+</span> <span class="n">A</span><span class="p">)</span> <span class="c1"># [ 0 2 4 6 8 10]</span>
<span class="nb">print</span><span class="p">(</span><span class="n">A</span> <span class="o">-</span> <span class="mi">1</span><span class="p">)</span> <span class="c1"># [-1 0 1 2 3 4]</span>
<span class="nb">print</span><span class="p">(</span><span class="n">A</span> <span class="o">*</span> <span class="mi">6</span><span class="p">)</span> <span class="c1"># [ 0 6 12 18 24 30]</span>
<span class="c1"># gradient</span>
<span class="n">X</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">array</span><span class="p">([</span><span class="mi">2</span><span class="p">,</span> <span class="mi">4</span><span class="p">,</span> <span class="mi">5</span><span class="p">])</span>
<span class="n">Y</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">array</span><span class="p">([</span><span class="mi">6</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">8</span><span class="p">])</span>
<span class="nb">print</span><span class="p">(</span><span class="n">np</span><span class="o">.</span><span class="n">gradient</span><span class="p">(</span><span class="n">X</span><span class="p">))</span>
<span class="c1"># [ 2. 1.5 1. ] => (4 - 2) / 1, (5 - 2) / 2, (5 - 4)/ 1</span>
<span class="nb">print</span><span class="p">(</span><span class="n">np</span><span class="o">.</span><span class="n">gradient</span><span class="p">(</span><span class="n">Y</span><span class="p">))</span>
<span class="c1"># [-4. 1. 6.] => (2 - 6) / 1, (8 - 6) / 2, (8 - 2)/ 1</span>
<span class="c1"># numerical derivative</span>
<span class="nb">print</span><span class="p">(</span><span class="n">np</span><span class="o">.</span><span class="n">gradient</span><span class="p">(</span><span class="n">Y</span><span class="p">)</span> <span class="o">/</span> <span class="n">np</span><span class="o">.</span><span class="n">gradient</span><span class="p">(</span><span class="n">X</span><span class="p">))</span>
<span class="c1"># [-2. 0.66666667 6. ]</span>
<span class="n">B</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">arange</span><span class="p">(</span><span class="mi">4</span><span class="p">)</span>
<span class="n">B</span><span class="o">.</span><span class="n">shape</span> <span class="o">=</span> <span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="mi">2</span><span class="p">)</span>
<span class="c1"># [[0 1]</span>
<span class="c1"># [2 3]]</span>
<span class="n">v</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">array</span><span class="p">([[</span><span class="mi">2</span><span class="p">],[</span><span class="mi">4</span><span class="p">]])</span>
<span class="c1"># [[2]</span>
<span class="c1"># [4]]</span>
<span class="c1"># scalar (multiplication)</span>
<span class="nb">print</span><span class="p">(</span><span class="n">B</span> <span class="o">*</span> <span class="n">v</span><span class="p">)</span>
<span class="c1"># [[ 0 2]</span>
<span class="c1"># [ 8 12]]</span>
<span class="c1"># dot product</span>
<span class="nb">print</span><span class="p">(</span><span class="n">np</span><span class="o">.</span><span class="n">dot</span><span class="p">(</span><span class="n">B</span><span class="p">,</span> <span class="n">v</span><span class="p">))</span>
<span class="c1"># [[ 4]</span>
<span class="c1"># [16]]</span>
<span class="c1"># operations on higher dimensions</span>
<span class="n">M</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">arange</span><span class="p">(</span><span class="mi">12</span><span class="p">)</span>
<span class="n">M</span><span class="o">.</span><span class="n">shape</span> <span class="o">=</span> <span class="p">(</span><span class="mi">4</span><span class="p">,</span> <span class="mi">3</span><span class="p">)</span>
<span class="c1"># [[ 0 1 2]</span>
<span class="c1"># [ 3 4 5]</span>
<span class="c1"># [ 6 7 8]</span>
<span class="c1"># [ 9 10 11]]</span>
<span class="n">v</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">array</span><span class="p">([</span><span class="mi">16</span><span class="p">,</span> <span class="mi">17</span><span class="p">,</span> <span class="mi">18</span><span class="p">])</span>
<span class="nb">print</span><span class="p">(</span><span class="n">M</span> <span class="o">+</span> <span class="n">v</span><span class="p">)</span>
<span class="c1"># [[16 18 20]</span>
<span class="c1"># [19 21 23]</span>
<span class="c1"># [22 24 26]</span>
<span class="c1"># [25 27 29]]</span>
</pre></div>
</div><div class='col-12 box'><a class='dotted' href='#pandas-operators-py'>pandas-operators.py</a>[<a href='https://github.com/mxsjoberg/code/blob/master/python/misc/pandas-operators.py' name='pandas-operators-py' class='m-0'>github</a>]<div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">pandas</span> <span class="k">as</span> <span class="nn">pd</span>
<span class="c1"># creating series (one-dimensional array)</span>
<span class="n">simple_series</span> <span class="o">=</span> <span class="n">pd</span><span class="o">.</span><span class="n">Series</span><span class="p">([</span><span class="mi">42</span><span class="p">,</span> <span class="mi">55</span><span class="p">,</span> <span class="mi">73</span><span class="p">],</span> <span class="n">dtype</span><span class="o">=</span><span class="s1">'f8'</span><span class="p">)</span>
<span class="c1"># 0 42.0</span>
<span class="c1"># 1 55.0</span>
<span class="c1"># 2 73.0</span>
<span class="c1"># dtype: float64</span>
<span class="c1"># creating series with specified index</span>
<span class="n">index_series</span> <span class="o">=</span> <span class="n">pd</span><span class="o">.</span><span class="n">Series</span><span class="p">([</span><span class="mi">42</span><span class="p">,</span> <span class="mi">55</span><span class="p">,</span> <span class="mi">73</span><span class="p">],</span> <span class="n">index</span><span class="o">=</span><span class="p">[</span><span class="s2">"electron"</span><span class="p">,</span> <span class="s2">"proton"</span><span class="p">,</span> <span class="s2">"neutron"</span><span class="p">],</span> <span class="n">dtype</span><span class="o">=</span><span class="s1">'f8'</span><span class="p">)</span>
<span class="c1"># electron 42.0</span>
<span class="c1"># proton 55.0</span>
<span class="c1"># neutron 73.0</span>
<span class="c1"># dtype: float64</span>
<span class="c1"># accessing value in series</span>
<span class="nb">print</span><span class="p">(</span><span class="n">index_series</span><span class="p">[</span><span class="s2">"electron"</span><span class="p">])</span>
<span class="c1"># 42.0</span>
<span class="c1"># accessing multiple values in series (range)</span>
<span class="nb">print</span><span class="p">(</span><span class="n">index_series</span><span class="p">[</span><span class="s2">"electron"</span><span class="p">:</span><span class="s2">"neutron"</span><span class="p">])</span>
<span class="c1"># electron 42.0</span>
<span class="c1"># proton 55.0</span>
<span class="c1"># neutron 73.0</span>
<span class="c1"># dtype: float64</span>
<span class="c1"># accessing multiple values in series using indexing</span>
<span class="nb">print</span><span class="p">(</span><span class="n">index_series</span><span class="p">[</span><span class="mi">1</span><span class="p">:])</span>
<span class="c1"># proton 55.0</span>
<span class="c1"># neutron 73.0</span>
<span class="c1"># dtype: float64</span>
<span class="c1"># creating series from dictionary</span>
<span class="n">dict_series</span> <span class="o">=</span> <span class="n">pd</span><span class="o">.</span><span class="n">Series</span><span class="p">({</span> <span class="s2">"electron"</span><span class="p">:</span> <span class="mi">6</span><span class="p">,</span> <span class="s2">"neutron"</span><span class="p">:</span> <span class="mi">28</span><span class="p">,</span> <span class="s2">"proton"</span><span class="p">:</span> <span class="mi">496</span><span class="p">,</span> <span class="s2">"neutrino"</span><span class="p">:</span> <span class="mi">8128</span> <span class="p">})</span>
<span class="c1"># electron 6</span>
<span class="c1"># neutrino 8128</span>
<span class="c1"># neutron 28</span>
<span class="c1"># proton 496</span>
<span class="c1"># dtype: int64</span>
<span class="c1"># combining two series into one column</span>
<span class="nb">print</span><span class="p">(</span><span class="n">index_series</span> <span class="o">+</span> <span class="n">dict_series</span><span class="p">)</span>
<span class="c1"># electron 48.0</span>
<span class="c1"># neutrino NaN</span>
<span class="c1"># neutron 101.0</span>
<span class="c1"># proton 551.0</span>
<span class="c1"># dtype: float64</span>
<span class="c1"># combining two series as dataframe</span>
<span class="n">combined_series</span> <span class="o">=</span> <span class="n">pd</span><span class="o">.</span><span class="n">DataFrame</span><span class="p">({</span> <span class="s2">"A"</span><span class="p">:</span> <span class="n">index_series</span><span class="p">,</span> <span class="s2">"B"</span><span class="p">:</span> <span class="n">dict_series</span> <span class="p">})</span>
<span class="c1"># A B</span>
<span class="c1"># electron 42.0 6</span>
<span class="c1"># neutrino NaN 8128</span>
<span class="c1"># neutron 73.0 28</span>
<span class="c1"># proton 55.0 496</span>
<span class="c1"># accessing columns as series</span>
<span class="nb">print</span><span class="p">(</span><span class="n">combined_series</span><span class="p">[</span><span class="s2">"A"</span><span class="p">])</span>
<span class="c1"># electron 42.0</span>
<span class="c1"># neutrino NaN</span>
<span class="c1"># neutron 73.0</span>
<span class="c1"># proton 55.0</span>
<span class="c1"># Name: A, dtype: float64</span>
<span class="c1"># add new row with index</span>
<span class="n">append_series</span> <span class="o">=</span> <span class="n">combined_series</span><span class="o">.</span><span class="n">_append</span><span class="p">(</span><span class="n">pd</span><span class="o">.</span><span class="n">DataFrame</span><span class="p">({</span> <span class="s2">"A"</span><span class="p">:</span> <span class="p">[</span><span class="o">-</span><span class="mi">8128</span><span class="p">]</span> <span class="p">},</span> <span class="n">index</span><span class="o">=</span><span class="p">[</span><span class="s2">"antineutrino"</span><span class="p">]))</span>
<span class="c1"># A B</span>
<span class="c1"># electron 42.0 6.0</span>
<span class="c1"># neutrino NaN 8128.0</span>
<span class="c1"># neutron 73.0 28.0</span>
<span class="c1"># proton 55.0 496.0</span>
<span class="c1"># antineutrino -8128.0 NaN</span>
<span class="c1"># drop row</span>
<span class="n">append_series</span> <span class="o">=</span> <span class="n">append_series</span><span class="o">.</span><span class="n">drop</span><span class="p">(</span><span class="s2">"neutron"</span><span class="p">)</span>