common constant function

docs/src/apireference.md

@@ -212,10 +212,14 @@ VectorQuadraticTerm
 VectorQuadraticFunction
 ```
 
-Functions for getting and setting properties of sets.
+Functions for getting and setting properties of functions.
 
 ```@docs
 output_dimension
+constant(f::Union{ScalarAffineFunction, ScalarQuadraticFunction})
+constant(f::Union{VectorAffineFunction, VectorQuadraticFunction})
+constant(f::SingleVariable, ::DataType)
+constant(f::VectorOfVariables, T::DataType)
 ```
 
 ## Sets
@@ -258,6 +262,7 @@ Functions for getting and setting properties of sets.
 
 ```@docs
 dimension
+constant(s::EqualTo)
 ```
 
 ## Modifications

src/Bridges/quadtosocbridge.jl

@@ -63,7 +63,7 @@ end
 function QuadtoSOCBridge{T}(model, func::MOI.ScalarQuadraticFunction{T},
                             set::Union{MOI.LessThan{T},
                                        MOI.GreaterThan{T}}) where T
-    set_constant = MOIU.getconstant(set)
+    set_constant = MOI.constant(set)
     less_than = set isa MOI.LessThan
     if !less_than
         set_constant = -set_constant

src/Bridges/scalarizebridge.jl

@@ -4,11 +4,6 @@ scalar_set_type(::Type{<:MOI.Zeros}, T::Type) = MOI.EqualTo{T}
 scalar_set_type(::Type{<:MOI.Nonpositives}, T::Type) = MOI.LessThan{T}
 scalar_set_type(::Type{<:MOI.Nonnegatives}, T::Type) = MOI.GreaterThan{T}
 
-__constant(f::Union{MOI.ScalarAffineFunction, MOI.ScalarQuadraticFunction}, T::DataType) = MOI._constant(f)
-__constant(f::Union{MOI.VectorAffineFunction, MOI.VectorQuadraticFunction}, T::DataType) = MOI._constant(f)
-__constant(f::MOI.SingleVariable, T::DataType) = zero(T)
-__constant(f::MOI.VectorOfVariables, T::DataType) = zeros(T, length(f.variables))
-
 """
     ScalarizeBridge{T}
 
@@ -23,7 +18,7 @@ function ScalarizeBridge{T, F, S}(model::MOI.ModelLike,
                                   f::MOI.AbstractVectorFunction,
                                   set::VectorLPSet) where {T, F, S}
     dimension = MOI.output_dimension(f)
-    constants = __constant(f, T)
+    constants = MOI.constant(f, T)
     new_f = MOIU.scalarize(f, true)
     constraints = Vector{CI{F, S}}(undef, dimension)
     for i in 1:dimension
@@ -89,7 +84,7 @@ end
 function MOI.set(model::MOI.ModelLike, ::MOI.ConstraintFunction,
     bridge::ScalarizeBridge{T}, func) where T
     old_constants = bridge.constants
-    bridge.constants = __constant(func, T)
+    bridge.constants = MOI.constant(func, T)
     new_func = MOIU.scalarize(func, true)
     MOI.set.(model, MOI.ConstraintFunction(), bridge.scalar_constraints,
              new_func)

src/Bridges/vectorizebridge.jl

@@ -21,11 +21,11 @@ end
 function VectorizeBridge{T, F, S}(model::MOI.ModelLike,
                                   f::MOI.AbstractScalarFunction,
                                   set::MOI.AbstractScalarSet) where {T, F, S}
-    set_constant = MOIU.getconstant(set)
+    set_constant = MOI.constant(set)
     g = MOIU.operate(-, T, f, set_constant)
-    if -set_constant != MOI._constant(g)[1]
+    if -set_constant != MOI.constant(g)[1]
         # This means the constant in `f` was not zero
-        constant = MOI._constant(g)[1] + set_constant
+        constant = MOI.constant(g)[1] + set_constant
         throw(MOI.ScalarFunctionConstantNotZero{typeof(constant), typeof(f),
                                                 typeof(set)}(constant))
     end
@@ -98,7 +98,7 @@ function MOI.modify(model::MOI.ModelLike, bridge::VectorizeBridge,
 end
 function MOI.set(model::MOI.ModelLike, ::MOI.ConstraintSet,
                  bridge::VectorizeBridge, new_set::LPCone)
-    bridge.set_constant = MOIU.getconstant(new_set)
+    bridge.set_constant = MOI.constant(new_set)
     MOI.modify(model, bridge.vector_constraint,
                MOI.VectorConstantChange([-bridge.set_constant]))
 end

src/Utilities/functions.jl

@@ -64,12 +64,12 @@ function mapvariables(varmap::Function, f::MOI.VectorOfVariables)
     return MOI.VectorOfVariables(varmap.(f.variables))
 end
 function mapvariables(varmap::Function, f::Union{SAF, VAF})
-    typeof(f)(mapvariable.(varmap, f.terms), MOI._constant(f))
+    typeof(f)(mapvariable.(varmap, f.terms), MOI.constant(f))
 end
 function mapvariables(varmap::Function, f::Union{SQF, VQF})
     lin = mapvariable.(varmap, f.affine_terms)
     quad = mapvariable.(varmap, f.quadratic_terms)
-    return typeof(f)(lin, quad, MOI._constant(f))
+    return typeof(f)(lin, quad, MOI.constant(f))
 end
 mapvariables(varmap, f::MOI.AbstractFunction) = mapvariables(vi -> varmap[vi], f)
 mapvariables(varmap::Function, change::Union{MOI.ScalarConstantChange, MOI.VectorConstantChange}) = change
@@ -461,11 +461,11 @@ function removevariable(f::VVF, vi)
     VVF(_rmvar(f.variables, vi))
 end
 function removevariable(f::Union{SAF, VAF}, vi)
-    typeof(f)(_rmvar(f.terms, vi), MOI._constant(f))
+    typeof(f)(_rmvar(f.terms, vi), MOI.constant(f))
 end
 function removevariable(f::Union{SQF, VQF}, vi)
     terms = _rmvar.((f.affine_terms, f.quadratic_terms), Ref(vi))
-    typeof(f)(terms..., MOI._constant(f))
+    typeof(f)(terms..., MOI.constant(f))
 end
 
 """
@@ -1399,7 +1399,7 @@ function scalarize(f::MOI.VectorOfVariables, ignore_constants::Bool = false)
 end
 function scalarize(f::MOI.VectorAffineFunction{T}, ignore_constants::Bool = false) where T
     dimension = MOI.output_dimension(f)
-    constants = ignore_constants ? zeros(T, dimension) : MOI._constant(f)
+    constants = ignore_constants ? zeros(T, dimension) : MOI.constant(f)
     counting = count_terms(dimension, f.terms)
     functions = MOI.ScalarAffineFunction{T}[
         MOI.ScalarAffineFunction{T}(MOI.ScalarAffineTerm{T}[], constants[i]) for i in 1:dimension]
@@ -1413,7 +1413,7 @@ function scalarize(f::MOI.VectorAffineFunction{T}, ignore_constants::Bool = fals
 end
 function scalarize(f::MOI.VectorQuadraticFunction{T}, ignore_constants::Bool = false) where T
     dimension = MOI.output_dimension(f)
-    constants = ignore_constants ? zeros(T, dimension) : MOI._constant(f)
+    constants = ignore_constants ? zeros(T, dimension) : MOI.constant(f)
     counting_scalars = count_terms(dimension, f.affine_terms)
     counting_quadratics = count_terms(dimension, f.quadratic_terms)
     functions = MOI.ScalarQuadraticFunction{T}[

src/Utilities/sets.jl

@@ -1,12 +1,3 @@
-"""
-    getconstant(s::Union{MOI.EqualTo, MOI.GreaterThan, MOI.LessThan})
-
-Returns the constant of the set.
-"""
-getconstant(s::MOI.EqualTo) = s.value
-getconstant(s::MOI.GreaterThan) = s.lower
-getconstant(s::MOI.LessThan) = s.upper
-
 const DimensionUpdatableSets = Union{MOI.Reals,
                                      MOI.Zeros,
                                      MOI.Nonnegatives,
@@ -36,7 +27,7 @@ function shift_constant(set::Union{MOI.LessThan{T},
                                    MOI.GreaterThan{T},
                                    MOI.EqualTo{T}},
                         offset::T) where T
-    return typeof(set)(getconstant(set) + offset)
+    return typeof(set)(MOI.constant(set) + offset)
 end
 function shift_constant(set::MOI.Interval, offset)
     return MOI.Interval(set.lower + offset, set.upper + offset)

src/functions.jl

@@ -352,14 +352,44 @@ function _dicts(f::Union{ScalarQuadraticFunction, VectorQuadraticFunction})
             sum_dict(term_pair.(f.quadratic_terms)))
 end
 
-_constant(f::Union{ScalarAffineFunction, ScalarQuadraticFunction}) = f.constant
-_constant(f::Union{VectorAffineFunction, VectorQuadraticFunction}) = f.constants
+"""
+    constant(f::Union{ScalarAffineFunction, ScalarQuadraticFunction})
+
+Returns the constant term of the scalar function
+"""
+constant(f::Union{ScalarAffineFunction, ScalarQuadraticFunction}) = f.constant
+
+"""
+    constant(f::Union{VectorAffineFunction, VectorQuadraticFunction})
+
+Returns the vector of constant terms of the vector function
+"""
+constant(f::Union{VectorAffineFunction, VectorQuadraticFunction}) = f.constants
 
 function Base.isapprox(f::F, g::G; kwargs...) where {F<:Union{ScalarAffineFunction, ScalarQuadraticFunction, VectorAffineFunction, VectorQuadraticFunction},
                                                      G<:Union{ScalarAffineFunction, ScalarQuadraticFunction, VectorAffineFunction, VectorQuadraticFunction}}
-    isapprox(_constant(f), _constant(g); kwargs...) && all(dict_isapprox.(_dicts(f), _dicts(g); kwargs...))
+    isapprox(constant(f), constant(g); kwargs...) && all(dict_isapprox.(_dicts(f), _dicts(g); kwargs...))
 end
 
+constant(f::Union{ScalarAffineFunction, ScalarQuadraticFunction}, T::DataType) = constant(f)
+constant(f::Union{VectorAffineFunction, VectorQuadraticFunction}, T::DataType) = constant(f)
+
+"""
+    constant(f::SingleVariable, T::DataType)
+
+The constant term of a `SingleVariable` function is
+the zero value of the specified type `T`.
+"""
+constant(f::SingleVariable, T::DataType) = zero(T)
+
+"""
+    constant(f::VectorOfVariables, T::DataType)
+
+The constant term of a `VectorOfVariables` function is a
+vector of zero values of the specified type `T`.
+"""
+constant(f::VectorOfVariables, T::DataType) = zeros(T, length(f.variables))
+
 # isbits type, nothing to copy
 Base.copy(func::SingleVariable) = func
 
@@ -371,15 +401,15 @@ Base.copy(func::VectorOfVariables) = VectorOfVariables(copy(func.variables))
 Return a new affine function with a shallow copy of the terms and constant(s)
 from `func`.
 """
-Base.copy(func::F) where {F <: Union{ScalarAffineFunction, VectorAffineFunction}} = F(copy(func.terms), copy(_constant(func)))
+Base.copy(func::F) where {F <: Union{ScalarAffineFunction, VectorAffineFunction}} = F(copy(func.terms), copy(constant(func)))
 
 """
     copy(func::Union{ScalarQuadraticFunction, VectorQuadraticFunction})
 
 Return a new quadratic function with a shallow copy of the terms and constant(s)
 from `func`.
 """
-Base.copy(func::F) where {F <: Union{ScalarQuadraticFunction, VectorQuadraticFunction}} = F(copy(func.affine_terms), copy(func.quadratic_terms), copy(_constant(func)))
+Base.copy(func::F) where {F <: Union{ScalarQuadraticFunction, VectorQuadraticFunction}} = F(copy(func.affine_terms), copy(func.quadratic_terms), copy(constant(func)))
 
 # Define shortcuts for
 # SingleVariable -> ScalarAffineFunction

src/sets.jl

@@ -136,6 +136,15 @@ Interval(s::LessThan{<:AbstractFloat}) = Interval(typemin(s.upper), s.upper)
 Interval(s::EqualTo{<:Real}) = Interval(s.value, s.value)
 Interval(s::Interval) = s
 
+"""
+    constant(s::Union{EqualTo, GreaterThan, LessThan})
+
+Returns the constant of the set.
+"""
+constant(s::EqualTo) = s.value
+constant(s::GreaterThan) = s.lower
+constant(s::LessThan) = s.upper
+
 """
     SecondOrderCone(dimension)
 

test/Utilities/functions.jl

@@ -449,7 +449,7 @@ end
 @testset "Conversion to canonical form" begin
     function isapprox_ordered(f1::T, f2::T) where {T <: Union{MOI.ScalarAffineFunction, MOI.VectorAffineFunction}}
         ((MOI.term_indices.(f1.terms) == MOI.term_indices.(f2.terms)) &&
-         (MOI._constant(f1) ≈ MOI._constant(f2)) &&
+         (MOI.constant(f1) ≈ MOI.constant(f2)) &&
          (MOI.coefficient.(f1.terms) ≈ MOI.coefficient.(f2.terms)))
     end
     function test_canonicalization(f::T, expected::T) where {T <: Union{MOI.ScalarAffineFunction, MOI.VectorAffineFunction}}

test/Utilities/sets.jl

@@ -1,7 +1,7 @@
 @testset "Constant" begin
-    @test MOIU.getconstant(MOI.EqualTo(3)) == 3
-    @test MOIU.getconstant(MOI.GreaterThan(6)) == 6
-    @test MOIU.getconstant(MOI.LessThan(2)) == 2
+    @test MOI.constant(MOI.EqualTo(3)) == 3
+    @test MOI.constant(MOI.GreaterThan(6)) == 6
+    @test MOI.constant(MOI.LessThan(2)) == 2
 end
 
 @testset "Shifts" begin