feat: add iso_oscar_singular_*

- use it in some places
oscar-system · Nov 26, 2024 · 815f504 · 815f504
1 parent 5076ad2
commit 815f504
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Showing 5 changed files with 533 additions and 4 deletions.
diff --git a/docs/Project.toml b/docs/Project.toml
@@ -2,6 +2,7 @@
 Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
 DocumenterCitations = "daee34ce-89f3-4625-b898-19384cb65244"
 JSON = "682c06a0-de6a-54ab-a142-c8b1cf79cde6"
+Oscar = "f1435218-dba5-11e9-1e4d-f1a5fab5fc13"
 
 [compat]
 Documenter = "1.1"

diff --git a/src/Rings/Rings.jl b/src/Rings/Rings.jl
@@ -9,6 +9,7 @@ include("groebner/groebner.jl")
 include("solving.jl")
 include("MPolyQuo.jl")
 include("FractionalIdeal.jl")
+include("oscar_singular.jl")
 
 include("special_ideals.jl")
 

diff --git a/src/Rings/mpoly.jl b/src/Rings/mpoly.jl
@@ -132,6 +132,7 @@ mutable struct BiPolyArray{S}
   Ox::NCRing #Oscar Poly Ring or Algebra
   O::Vector{S}
   Sx # Singular Poly Ring or Algebra, poss. with different ordering
+  f #= isomorphism Ox -> Sx =#
   S::Singular.sideal
 
   function BiPolyArray(O::Vector{T}) where {T <: NCRingElem}
@@ -381,7 +382,8 @@ function singular_generators(B::IdealGens, monorder::MonomialOrdering=default_or
   # in case of quotient rings, monomial ordering is ignored so far in singular_poly_ring
   isa(B.gens.Ox, MPolyQuoRing) && return B.gens.S
   isdefined(B, :ord) && B.ord == monorder && monomial_ordering(B.Ox, Singular.ordering(base_ring(B.S))) == B.ord && return B.gens.S
-  SR = singular_poly_ring(B.Ox, monorder)
+  g = iso_oscar_singular_poly_ring(B.Ox, monorder)
+  SR = codomain(g)
   f = Singular.AlgebraHomomorphism(B.Sx, SR, gens(SR))
   S = Singular.map_ideal(f, B.gens.S)
   if isdefined(B, :ord) && B.ord == monorder
@@ -481,7 +483,6 @@ for T in [:MPolyRing, :(AbstractAlgebra.Generic.MPolyRing)]
 end
 end
 
-
 #Note: Singular crashes if it gets Nemo.ZZ instead of Singular.ZZ ((Coeffs(17)) instead of (ZZ))
 singular_coeff_ring(::ZZRing) = Singular.Integers()
 singular_coeff_ring(::QQField) = Singular.Rationals()
@@ -746,8 +747,10 @@ end
 
 function singular_assure(I::IdealGens)
   if !isdefined(I.gens, :S)
-    I.gens.Sx = singular_poly_ring(I.Ox; keep_ordering = I.keep_ordering)
-    I.gens.S = Singular.Ideal(I.Sx, elem_type(I.Sx)[I.Sx(x) for x = I.O])
+    g = iso_oscar_singular_poly_ring(I.Ox; keep_ordering = I.keep_ordering)
+    I.gens.Sx = codomain(g)
+    I.gens.f = g
+    I.gens.S = Singular.Ideal(I.gens.Sx, elem_type(I.gens.Sx)[g(x) for x = I.gens.O])
   end
   if I.isGB && (!isdefined(I, :ord) || I.ord == monomial_ordering(I.gens.Ox, internal_ordering(I.gens.Sx)))
     I.gens.S.isGB = true
@@ -794,6 +797,7 @@ function oscar_assure(B::BiPolyArray)
     else
       R = B.Ox
     end
+    #B.O = [preimage(B.f, x) for x = gens(B.S)]
     B.O = [R(x) for x = gens(B.S)]
   end
 end