source: git/kernel/khstd.cc @ bc669c

fieker-DuValspielwiese
Last change on this file since bc669c was 690e21e, checked in by Hans Schönemann <hannes@…>, 14 years ago
moved option marcos to options.h git-svn-id: file:///usr/local/Singular/svn/trunk@12466 2c84dea3-7e68-4137-9b89-c4e89433aadc
  • Property mode set to 100644
File size: 3.5 KB
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1/****************************************
2*  Computer Algebra System SINGULAR     *
3****************************************/
4/* $Id$ */
5/*
6* ABSTRACT:utils for hilbert driven kStd
7*/
8
9#include "mod2.h"
10#include "febase.h"
11#include "options.h"
12#include "polys.h"
13#include "intvec.h"
14#include "kutil.h"
15#include "stairc.h"
16#include "kstd1.h"
17#include "khstd.h"
18
19
20/*2
21* compare the given hilbert series with the current one,
22* delete not needed pairs (if possible)
23*/
24void khCheck( ideal Q, intvec *w, intvec *hilb, int &eledeg, int &count,
25              kStrategy strat)
26  /* ideal S=strat->Shdl, poly p=strat->P.p */
27/*
28* compute the number eledeg of elements with a degree >= deg(p) going into kStd,
29* p is already in S and for all further q going into S yields deg(q) >= deg(p),
30* the real computation is only done if the degree has changed,
31* then we have eledeg == 0 on this degree and we make:
32*   - compute the Hilbert series newhilb from S
33*     (hilb is the final Hilbert series)
34*   - in module case: check that all comp up to strat->ak are used
35*   - compute the eledeg from newhilb-hilb for the first degree deg with
36*     newhilb-hilb != 0
37*     (Remark: consider the Hilbert series with coeff. up to infinity)
38*   - clear the set L for degree < deg
39* the number count is only for statistics (in the caller initialise count = 0),
40* in order to get a first computation, initialise eledeg = 1 in the caller.
41* The weights w are needed in the module case, otherwise NULL.
42*/
43{
44  intvec *newhilb;
45  int deg,l,ln,mw;
46  pFDegProc degp;
47
48  eledeg--;
49  if (eledeg == 0)
50  {
51    degp=pFDeg;
52    // if weights for variables were given to std computations,
53    // then pFDeg == degp == kHomModDeg (see kStd)
54    if ((degp!=kModDeg) && (degp!=kHomModDeg)) degp=pTotaldegree;
55    // degp = pWDegree;
56    l = hilb->length()-1;
57    mw = (*hilb)[l];
58    newhilb = hHstdSeries(strat->Shdl,w,strat->kHomW,Q,strat->tailRing);
59    ln = newhilb->length()-1;
60    deg = degp(strat->P.p,currRing)-mw;
61    loop // compare the series in degree deg, try to increase deg -----------
62    {
63      if (deg < ln) // deg may be out of range
64      {
65        if (deg < l)
66          eledeg = (*newhilb)[deg]-(*hilb)[deg];
67        else
68          eledeg = (*newhilb)[deg];
69      }
70      else
71      {
72        if (deg < l)
73          eledeg = -(*hilb)[deg];
74        else // we have newhilb = hilb
75        {
76          if (strat->ak>0)
77          {
78            char *used_comp=(char*)omAlloc0(strat->ak+1);
79            int i;
80            for(i=strat->sl;i>0;i--)
81              used_comp[pGetComp(strat->S[i])]='\1';
82            for(i=strat->ak;i>0;i--)
83            {
84              if(used_comp[i]=='\0')
85              {
86                omFree((ADDRESS)used_comp);
87                delete newhilb;
88                return;
89              }
90            }
91            omFree((ADDRESS)used_comp);
92          }
93          while (strat->Ll>=0)
94          {
95            count++;
96            if(TEST_OPT_PROT)
97            {
98              PrintS("h");
99              mflush();
100            }
101            deleteInL(strat->L,&strat->Ll,strat->Ll,strat);
102          }
103          delete newhilb;
104          return;
105        }
106      }
107      if (eledeg > 0) // elements to delete
108        break;
109      else if (eledeg <0) // strange....see bug_43
110        return;
111      deg++;
112    } /* loop */
113    delete newhilb;
114    while ((strat->Ll>=0) && (degp(strat->L[strat->Ll].p,currRing)-mw < deg)) // the essential step
115    {
116      count++;
117      if(TEST_OPT_PROT)
118      {
119        PrintS("h");
120        mflush();
121      }
122      deleteInL(strat->L,&strat->Ll,strat->Ll,strat);
123    }
124  }
125}
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