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Remove unnecessary compare implementations #318

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Remove unnecessary compare implementations #318

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23 changes: 10 additions & 13 deletions src/comparison.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -308,20 +308,22 @@ ordering(p::AbstractPolynomialLike) = ordering(typeof(p))
# Without `Base.@pure`, TypedPolynomials allocates on Julia v1.6
# with `promote(x * y, x)`
Base.@pure function Base.cmp(
::AbstractMonomialOrdering,
v1::AbstractVariable,
v2::AbstractVariable,
)
return -cmp(name(v1), name(v2))
end

function compare(
function Base.:(==)(m1::AbstractMonomialLike, m2::AbstractMonomialLike)
return iszero(cmp(m1, m2))
end

function Base.cmp(
m1::AbstractMonomial,
m2::AbstractMonomial,
::Type{O},
) where {O<:AbstractMonomialOrdering}
)
s1, s2 = promote_variables(m1, m2)
return cmp(O(), exponents(s1), exponents(s2))
return cmp(ordering(m1)(), exponents(s1), exponents(s2))
end

# Implement this to make coefficients be compared with terms.
Expand All @@ -336,22 +338,17 @@ end
_cmp_coefficient(a, b) = 0

function Base.cmp(
ordering::O,
t1::AbstractTermLike,
t2::AbstractTermLike,
) where {O<:AbstractMonomialOrdering}
Δ = cmp(ordering, monomial(t1), monomial(t2))
)
Δ = cmp(monomial(t1), monomial(t2))
if iszero(Δ)
return _cmp_coefficient(coefficient(t1), coefficient(t2))
end
return Δ
end

function Base.cmp(t1::AbstractTermLike, t2::AbstractTermLike)
return cmp(ordering(t1)(), t1, t2)
end

Base.isless(t1::AbstractTermLike, t2::AbstractTermLike) = compare(t1, t2) < 0
Base.isless(t1::AbstractTermLike, t2::AbstractTermLike) = cmp(t1, t2) < 0

_last_lex_index(n, ::Type{LexOrder}) = n
_prev_lex_index(i, ::Type{LexOrder}) = i - 1
Expand Down
8 changes: 4 additions & 4 deletions src/default_polynomial.jl
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Expand Up @@ -93,7 +93,7 @@ Base.one(p::Polynomial) = one(typeof(p))
Base.zero(::Type{Polynomial{C,T,A}}) where {C,T,A} = Polynomial{C,T,A}(A())
Base.zero(t::Polynomial) = zero(typeof(t))

compare_monomials(a, b) = compare(monomial(a), monomial(b))
compare_monomials(a, b) = cmp(monomial(a), monomial(b))

function join_terms(
terms1::AbstractArray{<:Term},
Expand Down Expand Up @@ -294,7 +294,7 @@ function __polynomial_merge!(
if tp isa Int && j isa Int
tp = get1(tp)
end
compare(monomial(*(monomials(q)[j], monomial.(t)...)), monomial(tp))
cmp(monomial(*(monomials(q)[j], monomial.(t)...)), monomial(tp))
end
end
get2 = let t = t, q = q
Expand Down Expand Up @@ -385,7 +385,7 @@ function __polynomial_merge!(
if tp isa Int && j isa Int
tp = get1(tp)
end
compare(monomial(monomial(t) * monomials(q)[j]), monomial(tp))
cmp(monomial(monomial(t) * monomials(q)[j]), monomial(tp))
end
end
get2 = let t = t, q = q
Expand Down Expand Up @@ -460,7 +460,7 @@ function __polynomial_merge!(
if t isa Int && j isa Int
t = get1(t)
end
compare(monomials(q)[j], monomial(t))
cmp(monomials(q)[j], monomial(t))
end
end
get2 = let q = q
Expand Down
2 changes: 1 addition & 1 deletion src/sequences.jl
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Expand Up @@ -18,7 +18,7 @@ function merge_sorted!(
while i1 <= lastindex(v1) && i2 <= lastindex(v2)
x1 = v1[i1]
x2 = v2[i2]
Δ = compare(x1, x2)
Δ = cmp(x1, x2)
if Δ < 0
if filter(x1)
result[i] = x1
Expand Down
45 changes: 22 additions & 23 deletions test/commutative/comparison.jl
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Expand Up @@ -141,28 +141,27 @@
@test p !== nothing
@test p !== Dict{Int,Int}()
end
@testset "compare" begin
lex = LexOrder
grlex = Graded{lex}
rinvlex = Reverse{InverseLexOrder}
grevlex = Graded{rinvlex}
Mod.@polyvar x y z
# [CLO13, p. 58]
@test compare(x * y^2 * z^3, x^3 * y^2, lex) < 0
@test compare(x * y^2 * z^3, x^3 * y^2, grlex) > 0
@test compare(x * y^2 * z^3, x^3 * y^2, rinvlex) < 0
@test compare(x * y^2 * z^3, x^3 * y^2, grevlex) > 0
@test compare(x * y^2 * z^4, x * y * z^5, lex) > 0
@test compare(x * y^2 * z^4, x * y * z^5, grlex) > 0
@test compare(x * y^2 * z^4, x * y * z^5, rinvlex) > 0
@test compare(x * y^2 * z^4, x * y * z^5, grevlex) > 0
# [CLO13, p. 59]
@test compare(x^5 * y * z, x^4 * y * z^2, lex) > 0
@test compare(x^5 * y * z, x^4 * y * z^2, grlex) > 0
@test compare(x^5 * y * z, x^4 * y * z^2, rinvlex) > 0
@test compare(x^5 * y * z, x^4 * y * z^2, grevlex) > 0
# [CLO13] Cox, D., Little, J., & OShea, D.
# *Ideals, varieties, and algorithms: an introduction to computational algebraic geometry and commutative algebra*.
# Springer Science & Business Media, **2013**.
lex = LexOrder
grlex = Graded{lex}
rinvlex = Reverse{InverseLexOrder}
grevlex = Graded{rinvlex}
if Mod == DynamicPolynomials
@testset "compare $M" for M in [
lex,
grlex,
rinvlex,
grevlex,
]
Mod.@polyvar x y z monomial_order = M
# [CLO13, p. 58]
sgn = (M == lex || M == rinvlex) ? -1 : 1
@test sgn * cmp(x * y^2 * z^3, x^3 * y^2) > 0
@test cmp(x * y^2 * z^4, x * y * z^5) > 0
# [CLO13, p. 59]
@test cmp(x^5 * y * z, x^4 * y * z^2) > 0
# [CLO13] Cox, D., Little, J., & OShea, D.
# *Ideals, varieties, and algorithms: an introduction to computational algebraic geometry and commutative algebra*.
# Springer Science & Business Media, **2013**.
end
end
end
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