feat: support complex coefficient GCD

Author: AayushSabharwal

src/gcd.jl

@@ -79,9 +79,16 @@ end
 _coefficient_gcd(α, β) = gcd(α, β)
 _coefficient_gcd(α::AbstractFloat, β) = one(Base.promote_typeof(α, β))
 _coefficient_gcd(α, β::AbstractFloat) = one(Base.promote_typeof(α, β))
+_coefficient_gcd(α::Complex, β) = one(Base.promote_typeof(α, β))
+_coefficient_gcd(α, β::Complex) = one(Base.promote_typeof(α, β))
+_coefficient_gcd(α::Complex, β::AbstractFloat) = one(Base.promote_typeof(α, β))
+_coefficient_gcd(α::AbstractFloat, β::Complex) = one(Base.promote_typeof(α, β))
 function _coefficient_gcd(α::AbstractFloat, β::AbstractFloat)
     return one(Base.promote_typeof(α, β))
 end
+function _coefficient_gcd(α::Complex, β::Complex)
+    return one(Base.promote_typeof(α, β))
+end
 
 function Base.lcm(
     p::_APL,

test/commutative/gcd.jl

@@ -298,4 +298,12 @@ end
         g = @inferred gcd(p1, p2)
         @test isone(g)
     end
+
+    @testset "Complex coefficient GCD" begin
+        Mod.@polyvar p q
+        p1 = MP.polynomial(p^2 + q^2, ComplexF64)
+        p2 = MP.polynomial(p * q, ComplexF64)
+        g = @inferred gcd(p1, p2)
+        @test isone(g)
+    end
 end