complete_reduction for reduce (#682)

src/ideal/ideal.jl

@@ -689,10 +689,14 @@ left reduction, and hence cannot be used to test containment in a two-sided idea
 For LETTERPLACE rings (S <: slpalg, FreeAlgebra), the reduction is two-sided as
 only two-sided ideals can be constructed here.
 """
-function reduce(I::sideal{S}, G::sideal{S}) where S <: SPolyUnion
+function reduce(I::sideal{S}, G::sideal{S};complete_reduction::Bool = true) where S <: SPolyUnion
  check_parent(I, G)
  R = base_ring(I)
- ptr = GC.@preserve I G R libSingular.p_Reduce(I.ptr, G.ptr, R.ptr)
+ if complete_reduction
+ ptr = GC.@preserve I G R libSingular.p_Reduce(I.ptr, G.ptr, R.ptr)
+ else
+ ptr = GC.@preserve I G R libSingular.p_Reduce(I.ptr, G.ptr, R.ptr,1)
+ end
  return sideal{S}(R, ptr, false, I.isTwoSided)
 end
 
@@ -706,10 +710,14 @@ left reduction, and hence cannot be used to test membership in a two-sided ideal
 For LETTERPLACE rings (S <: slpalg, FreeAlgebra), the reduction is the full
 two-sided reduction as only two-sided ideals can be constructed here.
 """
-function reduce(p::S, G::sideal{S}) where S <: SPolyUnion
+function reduce(p::S, G::sideal{S};complete_reduction = true) where S <: SPolyUnion
  R = parent(p)
  R == base_ring(G) || error("Incompatible base rings")
- ptr = GC.@preserve p G R libSingular.p_Reduce(p.ptr, G.ptr, R.ptr)
+ if complete_reduction
+ ptr = GC.@preserve p G R libSingular.p_Reduce(p.ptr, G.ptr, R.ptr)
+ else
+ ptr = GC.@preserve p G R libSingular.p_Reduce(p.ptr, G.ptr, R.ptr,1)
+ end
  return R(ptr)
 end