fix: fix comparison involving NaN

src/comparison.jl

@@ -21,29 +21,33 @@ Base.:(==)(x::RationalPoly, α::Nothing) = false
 Base.:(==)(α::Dict, x::RationalPoly) = false
 Base.:(==)(x::RationalPoly, α::Dict) = false
 
-function right_term_eq(p::AbstractPolynomial, t)
+function right_term_eq(p::AbstractPolynomial, t; comp = (==))
     if iszero(p)
         iszero(t)
     else
         # terms/nterms ignore zero terms
-        nterms(p) == 1 && leading_term(p) == t
+        nterms(p) == 1 && comp(leading_term(p), t)
     end
 end
-right_term_eq(p::_APL, t) = right_term_eq(polynomial(p), t)
+right_term_eq(p::_APL, t; comp = (==)) = right_term_eq(polynomial(p), t; comp)
 
-left_constant_eq(α, v::AbstractVariable) = false
-right_constant_eq(v::AbstractVariable, α) = false
-function _term_constant_eq(t::AbstractTermLike, α)
+left_constant_eq(α, v::AbstractVariable; comp = (==)) = false
+right_constant_eq(v::AbstractVariable, α; comp = (==)) = false
+function _term_constant_eq(t::AbstractTermLike, α; comp = (==))
     if iszero(t)
         iszero(α)
     else
-        α == coefficient(t) && isconstant(t)
+        comp(α, coefficient(t)) && isconstant(t)
     end
 end
-left_constant_eq(α, t::AbstractTermLike) = _term_constant_eq(t, α)
-right_constant_eq(t::AbstractTermLike, α) = _term_constant_eq(t, α)
-left_constant_eq(α, p::_APL) = right_term_eq(p, α)
-right_constant_eq(p::_APL, α) = right_term_eq(p, α)
+function left_constant_eq(α, t::AbstractTermLike; comp = (==))
+    return _term_constant_eq(t, α; comp)
+end
+function right_constant_eq(t::AbstractTermLike, α; comp = (==))
+    return _term_constant_eq(t, α; comp)
+end
+left_constant_eq(α, p::_APL; comp = (==)) = right_term_eq(p, α; comp)
+right_constant_eq(p::_APL, α; comp = (==)) = right_term_eq(p, α; comp)
 
 function Base.:(==)(mono::AbstractMonomial, v::AbstractVariable)
     return isone(degree(mono)) && variable(mono) == v
@@ -58,17 +62,28 @@ function Base.:(==)(mono::AbstractMonomialLike, t::AbstractTerm)
     return isone(coefficient(t)) && mono == monomial(t)
 end
 
-function Base.:(==)(t1::AbstractTerm, t2::AbstractTerm)
+function _compare_term(t1::AbstractTerm, t2::AbstractTerm, comp)
     c1 = coefficient(t1)
     c2 = coefficient(t2)
     if iszero(c1)
         iszero(c2)
     else
-        c1 == c2 && monomial(t1) == monomial(t2)
+        comp(c1, c2) && comp(monomial(t1), monomial(t2))
     end
 end
+
+Base.:(==)(t1::AbstractTerm, t2::AbstractTerm) = _compare_term(t1, t2, ==)
 Base.:(==)(p::AbstractPolynomial, t::AbstractTerm) = right_term_eq(p, t)
 Base.:(==)(t::AbstractTerm, p::AbstractPolynomial) = right_term_eq(p, t)
+function Base.isequal(t1::AbstractTerm, t2::AbstractTerm)
+    return _compare_term(t1, t2, isequal)
+end
+function Base.isequal(p::AbstractPolynomial, t::AbstractTerm)
+    return right_term_eq(p, t; comp = isequal)
+end
+function Base.isequal(t::AbstractTerm, p::AbstractPolynomial)
+    return right_term_eq(p, t; comp = isequal)
+end
 
 function compare_terms(p1::AbstractPolynomial, p2::AbstractPolynomial, isz, op)
     i1 = 1
@@ -110,13 +125,24 @@ end
 function Base.:(==)(p1::AbstractPolynomial, p2::AbstractPolynomial)
     return compare_terms(p1, p2, iszero, ==)
 end
+function Base.isequal(p1::AbstractPolynomial, p2::AbstractPolynomial)
+    return compare_terms(p1, p2, iszero, isequal)
+end
 
 Base.:(==)(p::RationalPoly, q::RationalPoly) = p.num * q.den == q.num * p.den
 # Solve ambiguity with (::PolyType, ::Any)
 Base.:(==)(p::_APL, q::RationalPoly) = p * q.den == q.num
 Base.:(==)(q::RationalPoly, p::_APL) = p == q
 Base.:(==)(α, q::RationalPoly) = α * q.den == q.num
 Base.:(==)(q::RationalPoly, α) = α == q
+function Base.isequal(p::RationalPoly, q::RationalPoly)
+    return isequal(p.num * q.den, q.num * p.den)
+end
+# Solve ambiguity with (::PolyType, ::Any)
+Base.isequal(p::_APL, q::RationalPoly) = isequal(p * q.den, q.num)
+Base.isequal(q::RationalPoly, p::_APL) = isequal(p, q)
+Base.isequal(α, q::RationalPoly) = isequal(α * q.den, q.num)
+Base.isequal(q::RationalPoly, α) = isequal(α, q)
 
 # α could be a JuMP affine expression
 isapproxzero(α; ztol::Real = 0.0) = false

test/commutative/comparison.jl

@@ -159,4 +159,29 @@
             # Springer Science & Business Media, **2013**.
         end
     end
+
+    @testset "Comparison with NaN" begin
+        Mod.@polyvar x y
+        @testset "$poly1 and $poly2" for (poly1, poly2) in [
+            (NaN * x, NaN * x),
+            (NaN * x + 0, NaN * x + 0),
+            (NaN * x, NaN * x + 0),
+            (NaN * x / y, NaN * x / y),
+            (x / (NaN * y), x / (NaN * y)),
+            ((NaN * x) / (NaN * y), (NaN * x) / (NaN * y)),
+            ((NaN * x + 0) / (NaN * y + 0), (NaN * x + 0) / (NaN * y + 0)),
+        ]
+            @test poly1 != poly2
+            @test poly1 != poly1
+            @test isequal(poly1, poly2)
+            @test isequal(poly1, poly1)
+            # RationalPoly equality multiplies and thus allocates
+            if !(poly1 isa RationalPoly)
+                @test (@allocated poly1 != poly2) == 0
+                @test (@allocated poly1 != poly1) == 0
+                @test (@allocated isequal(poly1, poly2)) == 0
+                @test (@allocated isequal(poly1, poly1)) == 0
+            end
+        end
+    end
 end