[FileFormats.SDPA] fix reading files with {} punctuation (#2759)

Author: odow

src/FileFormats/SDPA/SDPA.jl

@@ -302,18 +302,15 @@ function _dim_to_set(s::AbstractString)
     end
 end
 
-function _parse_dimensions(dims::AbstractString)
-    isvalid(char) = isdigit(char) || char == '-'
-    is_delimiter(char) = isspace(char) || char == ','
-    start = findfirst(isvalid, dims)
-    if start === nothing
-        return Union{MOI.PositiveSemidefiniteConeTriangle,MOI.Nonnegatives}[]
-    end
-    stop = findlast(isvalid, dims)::Int
-    s = split(dims[start:stop], is_delimiter)
-    return Union{MOI.PositiveSemidefiniteConeTriangle,MOI.Nonnegatives}[
-        _dim_to_set(dim) for dim in filter!(!isempty, s)
-    ]
+function _split(line)
+    # In some variations of SDPA, there is the comment:
+    #
+    # The special characters `,`, `(`, `)`, `{`, and `}` can be used as
+    # punctuation and are ignored.
+    #
+    # As one example, see https://github.com/vsdp/SDPLIB
+    line = replace(line, r"[,{}\(\)]"=>' ')
+    return split(line)
 end
 
 """
@@ -365,19 +362,20 @@ function Base.read!(io::IO, model::Model{T}) where {T<:Real}
             num_variables_read = true
             # According to http://plato.asu.edu/ftp/sdpa_format.txt,
             # additional text after the number of variables should be ignored.
-            scalar_vars = MOI.add_variables(model, parse(Int, split(line)[1]))
+            scalar_vars =
+                MOI.add_variables(model, parse(Int, first(_split(line))))
         elseif num_blocks === nothing
             if isempty(line)
                 continue
             end
             # According to http://plato.asu.edu/ftp/sdpa_format.txt,
             # additional text after the number of blocks should be ignored.
-            num_blocks = parse(Int, split(line)[1])
+            num_blocks = parse(Int, first(_split(line)))
         elseif !block_sets_read
             if isempty(line) && !iszero(num_blocks)
                 continue
             end
-            block_sets = _parse_dimensions(line)
+            block_sets = _dim_to_set.(_split(line))
             block_sets_read = true
             if length(block_sets) != num_blocks
                 error(
@@ -399,7 +397,7 @@ function Base.read!(io::IO, model::Model{T}) where {T<:Real}
                 continue
             end
             objective_read = true
-            c = parse.(T, split(line))
+            c = parse.(T, _split(line))
             if length(c) != num_vars
                 error(
                     "The number of variables ($num_vars) does not match the length of the list of coefficients for the objective function vector of coefficients ($(length(c))).",
@@ -416,7 +414,7 @@ function Base.read!(io::IO, model::Model{T}) where {T<:Real}
             if isempty(line)
                 continue
             end
-            values = split(line)
+            values = _split(line)
             if length(values) != 5
                 error(
                     "Invalid line specifying entry: $line. There are $(length(values)) values instead of 5.",

test/FileFormats/SDPA/SDPA.jl

@@ -323,26 +323,19 @@ function test_examples()
 end
 
 # See https://github.com/jump-dev/MathOptInterface.jl/issues/1541
-function _spacer(char)
-    return [" ", "$char", " $char", "$char ", " $char "]
-end
+_spacer(char) = [" ", "$char", " $char", "$char ", " $char "]
 
 function test_dim_reader()
-    for before in _spacer('{')
-        for sep in _spacer(',')
-            for after in _spacer('}')
-                line = string(before, "-4", sep, "2", after)
-                exp = [
-                    MOI.Nonnegatives(4),
-                    MOI.PositiveSemidefiniteConeTriangle(2),
-                ]
-                @test MOI.FileFormats.SDPA._parse_dimensions(line) == exp
-                line = string(before, "2", sep, "-4", after)
-                @test MOI.FileFormats.SDPA._parse_dimensions(line) ==
-                      exp[2:-1:1]
-            end
+    fn(line) = SDPA._dim_to_set.(SDPA._split(line))
+    for (a, b) in ['{' => '}', '(' => ')']
+        for pre in _spacer(a), sep in _spacer(','), suf in _spacer(b)
+            @test fn("$(pre)-4$(sep)2$suf") ==
+                  [MOI.Nonnegatives(4), MOI.PositiveSemidefiniteConeTriangle(2)]
+            @test fn("$(pre)2$(sep)-4$suf") ==
+                  [MOI.PositiveSemidefiniteConeTriangle(2), MOI.Nonnegatives(4)]
         end
     end
+    return
 end
 
 function test_integer_before_variables()

test/FileFormats/SDPA/models/issue_1541.dat-s

@@ -1,7 +1,7 @@
 3 =mdim
 2 =nblocks
 {-4, 2}
--0.0 -1 -2
+{-0.0,-1e+0, -2}
 0 1 1 1 -1
 1 1 1 1 -1
 1 1 2 2 1