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lift.cc
Go to the documentation of this file.
#include "polys/monomials/p_polys.h"
#include "witness.h"
/***
* Suppose r and s are the same ring but with two adjacent orderings,
* w is a weight vector in the relative interior of their common facet.
* Given a standard basis of an ideal I with respect to the ordering of r,
* a standard basis of its w-initial ideal inI with respect to
* the ordering of s, computes a standard basis of I with respect to
* the ordering of s.
**/
// ideal lift(const ideal I, const ring r, const ideal inI, const ring s)
// {
// nMapFunc identity = n_SetMap(r->cf,s->cf);
// int k = IDELEMS(I); ideal Is = idInit(k);
// for (int i=0; i<k; i++)
// Is->m[i] = p_PermPoly(I->m[i],NULL,r,s,identity,NULL,0);
// ideal J = idInit(k);
// for (int i=0; i<k; i++)
// J->m[i] = witness(inI->m[i],Is,inI,s);
// id_Delete(&Is,s);
// return J;
// }
ideal lift(const ideal J, const ring r, const ideal inI, const ring s)
{
nMapFunc identity = n_SetMap(s->cf,r->cf);
int k = IDELEMS(inI); ideal inIr = idInit(k);
for (int i=0; i<k; i++)
{
if(inI->m[i]!=NULL)
{
inIr->m[i] = p_PermPoly(inI->m[i],NULL,s,r,identity,NULL,0);
}
}
ideal Ir = witness(inIr,J,r);
identity = n_SetMap(r->cf,s->cf);
ideal Is = idInit(k);
for (int i=0; i<k; i++)
{
if(Ir->m[i]!=NULL)
{
Is->m[i] = p_PermPoly(Ir->m[i],NULL,r,s,identity,NULL,0);
}
}
id_Delete(&inIr,r);
id_Delete(&Ir,r);
return Is;
}
i
int i
Definition cfEzgcd.cc:132
k
int k
Definition cfEzgcd.cc:99
n_SetMap
static FORCE_INLINE nMapFunc n_SetMap(const coeffs src, const coeffs dst)
set the mapping function pointers for translating numbers from src to dst
Definition coeffs.h:703
nMapFunc
number(* nMapFunc)(number a, const coeffs src, const coeffs dst)
maps "a", which lives in src, into dst
Definition coeffs.h:80
s
const CanonicalForm int s
Definition facAbsFact.cc:51
lift
ideal lift(const ideal J, const ring r, const ideal inI, const ring s)
Definition lift.cc:26
NULL
#define NULL
Definition omList.c:12
p_PermPoly
poly p_PermPoly(poly p, const int *perm, const ring oldRing, const ring dst, nMapFunc nMap, const int *par_perm, int OldPar, BOOLEAN use_mult)
Definition p_polys.cc:4256
p_polys.h
idInit
ideal idInit(int idsize, int rank)
initialise an ideal / module
Definition simpleideals.cc:35
id_Delete
void id_Delete(ideal *h, ring r)
deletes an ideal/module/matrix
Definition simpleideals.cc:123
IDELEMS
#define IDELEMS(i)
Definition simpleideals.h:23
witness
poly witness(const poly m, const ideal I, const ideal inI, const ring r)
Let w be the uppermost weight vector in the matrix defining the ordering on r.
Definition witness.cc:34
witness.h