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Fix complex value substitution in Complex{Num} expressions #1710

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Fix complex value substitution in Complex{Num} expressions #1710

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33 changes: 24 additions & 9 deletions src/complex.jl
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Original file line number Diff line number Diff line change
@@ -1,11 +1,11 @@
SymbolicUtils.promote_symtype(::typeof(imag), ::Type{Complex{T}}) where {T} = T
Base.promote_rule(::Type{Complex{T}}, ::Type{S}) where {T<:Real, S<:Num} = Complex{S} # 283
Base.promote_rule(::Type{Complex{T}}, ::Type{S}) where {T <: Real, S <: Num} = Complex{S} # 283

is_wrapper_type(::Type{Complex{Num}}) = true
has_symwrapper(::Type{<:Complex{T}}) where {T<:Real} = true
has_symwrapper(::Type{<:Complex{T}}) where {T <: Real} = true
wraps_type(::Type{Complex{Num}}) = Complex{Real}
iswrapped(::Complex{Num}) = true
function wrapper_type(::Type{Complex{T}}) where T
function wrapper_type(::Type{Complex{T}}) where {T}
Symbolics.has_symwrapper(T) ? Complex{wrapper_type(T)} : Complex{T}
end

Expand All @@ -14,11 +14,13 @@ function SymbolicUtils.unwrap(a::Complex{<:Num})
if SymbolicUtils.isconst(re) && SymbolicUtils.isconst(img)
return Const{VartypeT}(complex(unwrap_const(re), unwrap_const(img)))
end
if iscall(re) && operation(re) === real && iscall(img) && operation(img) === imag && isequal(arguments(re)[1], arguments(img)[1])
if iscall(re) && operation(re) === real && iscall(img) && operation(img) === imag &&
isequal(arguments(re)[1], arguments(img)[1])
return arguments(re)[1]
end
sT = promote_type(symtype(re), symtype(img))
return Term{VartypeT}(complex, SymbolicUtils.ArgsT{vartype(re)}((re, img)); type = Complex{sT}, shape = SymbolicUtils.ShapeVecT())
return Term{VartypeT}(complex, SymbolicUtils.ArgsT{vartype(re)}((re, img));
type = Complex{sT}, shape = SymbolicUtils.ShapeVecT())
end

function Base.Complex{Num}(x::BasicSymbolic{VartypeT})
Expand All @@ -32,15 +34,28 @@ function Base.show(io::IO, a::Complex{Num})
ii = unwrap(imag(a))

if iscall(rr) && (operation(rr) === real) &&
iscall(ii) && (operation(ii) === imag) &&
isequal(arguments(rr)[1], arguments(ii)[1])

iscall(ii) && (operation(ii) === imag) &&
isequal(arguments(rr)[1], arguments(ii)[1])
return print(io, arguments(rr)[1])
end

show(io, real(a) + IM * imag(a))
end

function (s::SymbolicUtils.Substituter)(x::Complex{Num})
Complex{Num}(s(real(x)), s(imag(x)))
re_sub = s(real(x))
im_sub = s(imag(x))
# Unwrap to check if the substituted values are complex constants
re_unwrapped = unwrap(re_sub)
im_unwrapped = unwrap(im_sub)
# If both parts are constants, we can evaluate the full complex expression
if SymbolicUtils.isconst(re_unwrapped) && SymbolicUtils.isconst(im_unwrapped)
re_val = SymbolicUtils.unwrap_const(re_unwrapped)
im_val = SymbolicUtils.unwrap_const(im_unwrapped)
# Properly handle complex arithmetic: (a + b*im) where a, b can be complex
# (a_re + a_im*im) + (b_re + b_im*im)*im = (a_re - b_im) + (a_im + b_re)*im
result = re_val + im_val * im
return Complex{Num}(wrap(Const{VartypeT}(real(result))), wrap(Const{VartypeT}(imag(result))))
end
Complex{Num}(re_sub, im_sub)
end
43 changes: 43 additions & 0 deletions test/complex.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -50,3 +50,46 @@ end
@test !hasname(2x)
@test !hasname(x + y)
end

# issue #1109: substituting complex values into expressions with complex coefficients
@testset "complex value substitution" begin
@variables x y

# Basic case from issue #1109
p1 = 0.4 + 1.7im * x
result1 = substitute(p1, Dict(x => 0.2 + 1.0im))
expected1 = 0.4 + 1.7im * (0.2 + 1.0im)
@test result1 isa Complex{Num}
@test isapprox(unwrap_const(unwrap(real(result1))), real(expected1))
@test isapprox(unwrap_const(unwrap(imag(result1))), imag(expected1))

# Both real and imag parts have the variable
p2 = x + 2.0im * x
result2 = substitute(p2, Dict(x => 1.0 + 0.5im))
expected2 = (1.0 + 0.5im) + 2.0im * (1.0 + 0.5im)
@test isapprox(unwrap_const(unwrap(real(result2))), real(expected2))
@test isapprox(unwrap_const(unwrap(imag(result2))), imag(expected2))

# Real value substitution still works
p3 = 0.4 + 1.7im * x
result3 = substitute(p3, Dict(x => 0.5))
expected3 = 0.4 + 1.7im * 0.5
@test isapprox(unwrap_const(unwrap(real(result3))), real(expected3))
@test isapprox(unwrap_const(unwrap(imag(result3))), imag(expected3))

# Two variables with complex substitution
p4 = x + y * im
result4 = substitute(p4, Dict(x => 1.0 + 2.0im, y => 3.0 + 4.0im))
expected4 = (1.0 + 2.0im) + (3.0 + 4.0im) * im
@test isapprox(unwrap_const(unwrap(real(result4))), real(expected4))
@test isapprox(unwrap_const(unwrap(imag(result4))), imag(expected4))

# Symbolics.value should work on the result
result_val = Symbolics.value(result1)
@test result_val isa Complex
@test isapprox(result_val, expected1)

# simplify and expand should work
@test_nowarn Symbolics.simplify(result1)
@test_nowarn Symbolics.expand(result1)
end
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