From 1b4adf745f417f6234fa8be6d3199ea9d4153025 Mon Sep 17 00:00:00 2001
From: Hans Schoenemann <hannes@mathematik.uni-kl.de>
Date: Tue, 21 Mar 2023 08:08:23 +0100
Subject: [PATCH] Add mstd, divrem back

---
 Project.toml       |  4 ++--
 src/ideal/ideal.jl | 37 ++++++++++++++++++++++++++++++++++++-
 2 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/Project.toml b/Project.toml
index b6ef933c4..6915c3957 100644
--- a/Project.toml
+++ b/Project.toml
@@ -23,9 +23,9 @@ BinaryWrappers = "~0.1.1"
 CxxWrap = "0.11, 0.12, 0.13"
 Nemo = "0.33.0"
 RandomExtensions = "0.4.2"
-Singular_jll = "~403.101.500"
+Singular_jll = "~403.201.000"
 julia = "1.6"
-libsingular_julia_jll = "~0.29.0"
+libsingular_julia_jll = "~0.30.0"
 
 [extras]
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
diff --git a/src/ideal/ideal.jl b/src/ideal/ideal.jl
index 26da99a0b..43bc90a8c 100644
--- a/src/ideal/ideal.jl
+++ b/src/ideal/ideal.jl
@@ -3,7 +3,7 @@ export sideal, IdealSet, syz, lead, normalize!, is_constant, is_zerodim, fglm,
        independent_sets, maximal_independent_set, ngens, sres, intersection,
        quotient, reduce, eliminate, kernel, equal, contains, is_var_generated,
        saturation, satstd, slimgb, std, vdim, interreduce, degree, mult,
-       hilbert_series, std_hilbert, is_homogeneous, division
+       hilbert_series, std_hilbert, is_homogeneous, division, divrem, mstd
 
 ###############################################################################
 #
@@ -542,6 +542,24 @@ function std(I::sideal{S}; complete_reduction::Bool=false) where S <: SPolyUnion
    return sideal{S}(R, ptr, true, I.isTwoSided)
 end
 
+@doc Markdown.doc"""
+    mstd(I::sideal{S}; complete_reduction::Bool=false) where S <: SPolyUnion
+
+Compute a Groebner basis for the ideal $I$ and a minimal generating set.
+Note that without `complete_reduction` set to `true`,
+the generators of the Groebner basis
+only have unique leading terms (up to permutation and multiplication by
+constants). If `complete_reduction` is set to `true` (and the ordering is
+a global ordering) then the Groebner basis is unique.
+"""
+function mstd(I::sideal{S}; complete_reduction::Bool=false) where S <: SPolyUnion
+   R = base_ring(I)
+   ptr,ptr_min = GC.@preserve I R libSingular.id_MinStd(I.ptr, R.ptr, complete_reduction)
+   libSingular.idSkipZeroes(ptr)
+   libSingular.idSkipZeroes(ptr_min)
+   return (sideal{S}(R, ptr), sideal{S}(R, ptr_min))
+end
+
 @doc Markdown.doc"""
     interreduce(I::sideal{S}) where {T <: Nemo.RingElem, S <: Union{spoly{T}, spluralg{T}}}
 
@@ -663,6 +681,23 @@ function division(I::sideal{S}, G::sideal{S}) where S <: SPolyUnion
    return (smodule{S}(R,ptr_T), sideal{S}(R,ptr_Rest), smodule{S}(R,ptr_U))
 end
 
+@doc Markdown.doc"""
+    divrem(I::sideal{S}, G::sideal{S}) where S <: SPolyUnion
+
+Computes a division with remainder of the generators of `I` by
+the generators of `G`. Returns a tuple (Quo, Rem, U) where
+  `Matrix(I)*Matrix(U) = Matrix(G)*Matrix(Quo) + Matrix(Rem)`
+and `Rem = normalform(I, G)`. `U` is a diagonal matrix of units differing
+from the identity matrix only for local ring orderings.
+"""
+function divrem(I::sideal{S}, G::sideal{S}) where S <: SPolyUnion
+   check_parent(I, G)
+   R = base_ring(I)
+   ptr_T,ptr_Rest,ptr_U = GC.@preserve I G R libSingular.id_DivRem_Unit(I.ptr, G.ptr,
+                                                      R.ptr)
+   return (smodule{S}(R,ptr_T), sideal{S}(R,ptr_Rest), smodule{S}(R,ptr_U))
+end
+
 ###############################################################################
 #
 #   Eliminate