Merge pull request #207 from c-bata/sobol-1000lines

Avoid to skip 1000 lines from the top of direction numbers.
c-bata · Feb 9, 2021 · d023ea9 · d023ea9
2 parents f0ff33b + 593ac5f
commit d023ea9
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Showing 3 changed files with 8 additions and 5 deletions.
diff --git a/_tools/codegen_sobol/main.go b/_tools/codegen_sobol/main.go
@@ -103,7 +103,7 @@ func main() {
 	fmt.Fprintf(fout, "\n")
 	fmt.Fprintf(fout, "// The original data of direction numbers is distributed at https://web.maths.unsw.edu.au/~fkuo/sobol/ (BSD License).\n")
 	fmt.Fprintf(fout, "\n")
-	fmt.Fprintf(fout, "const maxDim = 21201 - 1002  // Due to skip 1000 lines\n")
+	fmt.Fprintf(fout, "const maxDim = 21201 - 2\n")
 	fmt.Fprintf(fout, "const maxDeg = 18\n")
 	fmt.Fprintf(fout, "const maxBit = 30\n")
 	fmt.Fprintf(fout, "\n")

diff --git a/sobol/direction_numbers.go b/sobol/direction_numbers.go
diff --git a/sobol/engine.go b/sobol/engine.go
@@ -30,10 +30,13 @@ func initDirectionNumbers(dim uint32) [][]uint32 {
 		v[j] = make([]uint32, maxBit+1)
 
 		// Read in parameters from file
-		// Skip 1000 lines from the top as Joe&Kuo's C++ program do.
-		dn := directionNumbers[1000+j]
+		dn := directionNumbers[j]
+		m := make([]uint32, len(dn.M)+1)
+		for i := uint32(0); i < dn.S; i++ {
+			m[i+1] = dn.M[i]
+		}
 		for i := uint32(1); i <= dn.S; i++ {
-			v[j][i] = dn.M[i-1] << (32 - i)
+			v[j][i] = m[i] << (32 - i)
 		}
 		for i := dn.S + 1; i <= maxBit; i++ {
 			v[j][i] = v[j][i-dn.S] ^ (v[j][i-dn.S] >> dn.S)