Merge pull request #342 from tkoolen/tk/scalar-dim

Define dimension for AbstractScalarSet, add some tests.

Author: blegat

src/sets.jl

@@ -7,26 +7,43 @@ Abstract supertype for set objects used to encode constraints.
 """
 abstract type AbstractSet end
 
+"""
+    dimension(s::AbstractSet)
+
+Return the output dimension that an [`AbstractFunction`](@ref) should have to be used with the set `s`.
+
+### Examples
+
+```julia-repl
+julia> dimension(Reals(4))
+4
+
+julia> dimension(LessThan(3.0))
+1
+
+julia> dimension(PositiveSemidefiniteConeTriangle(2))
+3
+```
+
+"""
+function dimension end
+
 """
     AbstractScalarSet
 
 Abstract supertype for subsets of ``\\mathbb{R}``.
 """
 abstract type AbstractScalarSet <: AbstractSet end
 
+dimension(s::AbstractScalarSet) = 1
+
 """
     AbstractVectorSet
 
 Abstract supertype for subsets of ``\\mathbb{R}^n`` for some ``n``.
 """
 abstract type AbstractVectorSet <: AbstractSet end
 
-"""
-    dimension(s::AbstractVectorSet)
-
-Return the underlying dimension (number of vector components) in the set `s`, i.e.,
-``n`` if the set is a subset of ``\\mathbb{R}^n``.
-"""
 dimension(s::AbstractVectorSet) = s.dimension # .dimension field is conventional, overwrite this method if not applicable
 
 """

test/sets.jl

@@ -3,3 +3,16 @@
     @test MOIU.getconstant(MOI.GreaterThan(6)) == 6
     @test MOIU.getconstant(MOI.LessThan(2)) == 2
 end
+
+@testset "Set dimension" begin
+    @test MOI.dimension(MOI.EqualTo(3.0)) === 1
+    @test MOI.dimension(MOI.Reals(8)) === 8
+    @test MOI.dimension(MOI.DualExponentialCone()) === 3
+    @test MOI.dimension(MOI.PositiveSemidefiniteConeTriangle(4)) === 10
+    @test MOI.dimension(MOI.PositiveSemidefiniteConeSquare(5)) === 25
+    @test MOI.dimension(MOI.RootDetConeTriangle(6)) === 22
+    @test MOI.dimension(MOI.LogDetConeTriangle(6)) === 22
+    @test MOI.dimension(MOI.RootDetConeSquare(4)) === 17
+    @test MOI.dimension(MOI.LogDetConeSquare(4)) === 17
+    @test MOI.dimension(MOI.SOS2(collect(1 : 6))) === 6
+end