fix: fix comparison involving NaN (#178)

* fix: fix comparison involving `NaN`

* test: add allocation tests to NaN equality checking

Author: AayushSabharwal

src/comp.jl

@@ -58,25 +58,28 @@ end
 (==)(x::MonomialVector, mv::AbstractVector) = x == monomial_vector(mv)
 
 # Comparison of Term
-function (==)(p::Polynomial{V,M}, q::Polynomial{V,M}) where {V,M}
+function _compare(p::Polynomial{V,M}, q::Polynomial{V,M}, comparator) where {V,M}
     # terms should be sorted and without zeros
     if MP.nterms(p) != MP.nterms(q)
         return false
     end
     for i in eachindex(p.a)
-        if p.x[i] != q.x[i]
+        if !comparator(p.x[i], q.x[i])
             # There should not be zero terms
             @assert p.a[i] != 0
             @assert q.a[i] != 0
             return false
         end
-        if p.a[i] != q.a[i]
+        if !comparator(p.a[i], q.a[i])
             return false
         end
     end
     return true
 end
 
+(==)(p::Polynomial{V, M}, q::Polynomial{V, M}) where {V, M} = _compare(p, q, (==))
+Base.isequal(p::Polynomial{V, M}, q::Polynomial{V, M}) where {V, M} = _compare(p, q, isequal)
+
 function Base.isapprox(
     p::Polynomial{V,M,S},
     q::Polynomial{V,M,T};

test/comp.jl

@@ -97,3 +97,17 @@ end
     _test_monomials([x, y], 1:2, [y, x, y^2, x * y, x^2])
     _test_monomials([x, y], [0, 1, 3], [1, y, x, y^3, x*y^2, x^2*y, x^3])
 end
+
+@testset "Comparison with NaN" begin
+    @polyvar p
+    poly1 = NaN + p
+    poly2 = NaN + p
+    @test poly1 != poly2
+    @test (@allocated poly1 != poly2) == 0
+    @test poly1 != poly1
+    @test (@allocated poly1 != poly1) == 0
+    @test isequal(poly1, poly2)
+    @test (@allocated isequal(poly1, poly2)) == 0
+    @test isequal(poly1, poly1)
+    @test (@allocated isequal(poly1, poly1)) == 0
+end