Add only constant terms

Author: odow

src/Nonlinear/SymbolicAD/SymbolicAD.jl

@@ -241,39 +241,6 @@ function simplify!(::Val{:*}, f::MOI.ScalarNonlinearFunction)
     return f
 end
 
-# The MOI.Utilities.operate!(+, T, x, y) methods do not cope with mixed input
-# types. However, ScalarNonlinearFunction can hold various <:Real coefficient
-# types.
-_add_to!(x::Real, y::Real) = x + y
-
-_add_to!(x::Real, y::MOI.ScalarAffineFunction{<:Real}) = _add_to!(y, x)
-
-function _add_to!(x::MOI.ScalarAffineFunction{T}, y::T) where {T<:Real}
-    return MOI.Utilities.operate!(+, T, x, y)
-end
-
-function _add_to!(x::MOI.ScalarAffineFunction{S}, y::T) where {S<:Real,T<:Real}
-    U = promote_type(S, T)
-    F = MOI.ScalarAffineFunction{U}
-    return MOI.Utilities.operate!(+, U, convert(F, x), convert(U, y))
-end
-
-function _add_to!(
-    x::MOI.ScalarAffineFunction{T},
-    y::MOI.ScalarAffineFunction{T},
-) where {T<:Real}
-    return MOI.Utilities.operate!(+, T, x, y)
-end
-
-function _add_to!(
-    x::MOI.ScalarAffineFunction{S},
-    y::MOI.ScalarAffineFunction{T},
-) where {S<:Real,T<:Real}
-    U = promote_type(S, T)
-    F = MOI.ScalarAffineFunction{U}
-    return MOI.Utilities.operate!(+, U, convert(F, x), convert(F, y))
-end
-
 function simplify!(::Val{:+}, f::MOI.ScalarNonlinearFunction)
     new_args = Any[]
     first_affine_term = 0
@@ -283,14 +250,13 @@ function simplify!(::Val{:+}, f::MOI.ScalarNonlinearFunction)
             append!(new_args, arg.args)
         elseif _iszero(arg)
             # Skip any zero arguments
-        elseif arg isa Real || arg isa MOI.ScalarAffineFunction{<:Real}
+        elseif arg isa Real
             # Collect all affine arguments into a single value
             if first_affine_term == 0
                 push!(new_args, arg)
                 first_affine_term = length(new_args)
             else
-                new_args[first_affine_term] =
-                    _add_to!(new_args[first_affine_term], arg)
+                new_args[first_affine_term] += arg
             end
         else
             push!(new_args, arg)

test/Nonlinear/SymbolicAD.jl

@@ -348,32 +348,6 @@ function test_simplify_ScalarNonlinearFunction_addition()
     return
 end
 
-function test_simplify_ScalarNonlinearFunction_addition_terms()
-    x = MOI.VariableIndex(1)
-    for (args, ret) in Any[
-        # add_to!(::Real, ::Real)
-        Any[2.0, 3.0]=>5.0,
-        Any[2.5, 3]=>5.5,
-        Any[3, 2.5]=>5.5,
-        # add_to!(::ScalarAffineFunction{T}, ::ScalarAffineFunction{T})
-        Any[2.0*x, 3.0*x+4.0]=>5.0*x+4.0,
-        # add_to!(::ScalarAffineFunction{T}, ::T)
-        Any[2.0*x, 1.0]=>2.0*x+1.0,
-        # add_to!(::ScalarAffineFunction{S}, ::T)
-        Any[2.0*x, 3]=>2.0*x+3.0,
-        Any[2*x, 3.0]=>2.0*x+3.0,
-        # add_to!(::ScalarAffineFunction{S}, ::ScalarAffineFunction{T})
-        Any[2*x, 3.0*x+4.0]=>5.0*x+4.0,
-        Any[3.0*x+4.0, 2*x]=>5.0*x+4.0,
-        Any[3*x+4, 1.5, 2*x]=>5.0*x+5.5,
-        Any[1.5, 3*x+4, 2*x]=>5.0*x+5.5,
-    ]
-        f = MOI.ScalarNonlinearFunction(:+, args)
-        @test SymbolicAD.simplify(f) ≈ ret
-    end
-    return
-end
-
 # simplify(::Val{:-}, f::MOI.ScalarNonlinearFunction)
 function test_simplify_ScalarNonlinearFunction_subtraction()
     x, y = MOI.VariableIndex(1), MOI.VariableIndex(2)