Fixes

Author: blegat

src/comp.jl

@@ -40,8 +40,8 @@ function (==)(x::MonomialVector{V,M}, y::MonomialVector{V,M}) where {V,M}
     # Should be sorted in the same order since the non-common
     # polyvar should have exponent 0
     for (a, b) in zip(x.Z, y.Z)
-        A = zeros(length(allvars))
-        B = zeros(length(allvars))
+        A = zeros(Int, length(allvars))
+        B = zeros(Int, length(allvars))
         A[maps[1]] = a
         B[maps[2]] = b
         if A != B

src/monomial_vector.jl

@@ -1,10 +1,5 @@
 export MonomialVector
 
-struct AllMonomials{V,M} <: AbstractVector{Monomial{V,M}}
-    vars::Vector{Variable{V,M}}
-end
-Base.IteratorSize(::Type{<:AllMonomials}) = Base.IsInfinite()
-
 # Invariant: Always sorted and no zero vector
 struct MonomialVector{V,M} <: AbstractVector{Monomial{V,M}}
     vars::Vector{Variable{V,M}}
@@ -153,6 +148,15 @@ function _error_for_negative_degree(deg)
     end
 end
 
+const _Lex = Union{MP.LexOrder,MP.InverseLexOrder}
+
+_last_lex_index(n, ::Type{MP.LexOrder}) = n
+_prev_lex_index(i, ::Type{MP.LexOrder}) = i - 1
+_not_first_indices(n, ::Type{MP.LexOrder}) = n:-1:2
+_last_lex_index(_, ::Type{MP.InverseLexOrder}) = 1
+_prev_lex_index(i, ::Type{MP.InverseLexOrder}) = i + 1
+_not_first_indices(n, ::Type{MP.InverseLexOrder}) = 1:(n-1)
+
 function _fill_exponents!(Z, n, degs, ::Type{Commutative}, M::Type{<:_Lex}, filter::Function)
     _error_for_negative_degree.(degs)
     maxdeg = maximum(degs, init = 0)

src/var.jl

@@ -291,3 +291,15 @@ function mergevars_of(::Type{Variable{V,M}}, polys::AbstractVector) where {V,M}
     # TODO avoid computing `maps`
     return mergevars(varsvec)
 end
+
+function MP.promote_variables(m1::Monomial, m2::Monomial)
+    if MP.variables(m1) == MP.variables(m2)
+        return m1, m2
+    end
+    allvars, maps = mergevars([MP.variables(m1), MP.variables(m2)])
+    z1 = zeros(Int, length(allvars))
+    z1[maps[1]] = m1.z
+    z2 = zeros(Int, length(allvars))
+    z2[maps[2]] = m2.z
+    return Monomial(allvars, z1), Monomial(allvars, z2)
+end