Mkae monomial antidifferentiation coefficient types rationals

JuliaAlgebra · Apr 10, 2024 · 66274d3 · 66274d3
1 parent b76a367
commit 66274d3
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Showing 2 changed files with 7 additions and 1 deletion.
diff --git a/src/anti_diff.jl b/src/anti_diff.jl
@@ -13,7 +13,7 @@ function MP.antidifferentiate(m::Monomial{V,M}, x::Variable{V,M}) where {V,M}
         Monomial(MP.variables(m), z) * x
     else
         z[i] += 1
-        Monomial(MP.variables(m), z) / (m.z[i] + 1)
+        (1 // (m.z[i] + 1)) * Monomial(MP.variables(m), z)
     end
 end
 

diff --git a/test/mono.jl b/test/mono.jl
@@ -148,13 +148,19 @@ import MultivariatePolynomials as MP
         mi = DynamicPolynomials.MP.antidifferentiate(m, y)
         @test mi == x * y
 
+        # Antidifferentiation is product => Integral coefficients
+        @test MP.coefficient_type(mi) == Int
+
+        # General antidifferentiation => Rational coefficients
         m = x^3
         mi = DynamicPolynomials.MP.antidifferentiate(m, x)
         @test mi == (x^4 / 4)
+        @test MP.coefficient_type(mi) == Rational{Int}
 
         m = Monomial([x, y, z], [1, 2, 3])
         mi = DynamicPolynomials.MP.antidifferentiate(m, z)
         @test mi == (x*y^2*z^4) / 4
+        @test MP.coefficient_type(mi) == Rational{Int}
     end
 
     @testset "Evaluation" begin