Function Mwalk

Singular/walk.cc:5303–5601

* THE GROEBNER WALK ALGORITHM * *******************************/

 * THE GROEBNER WALK ALGORITHM *
 *******************************/
ideal Mwalk(ideal Go, intvec* orig_M, intvec* target_M,
            ring baseRing, int reduction, int printout)
{
  // save current options
  BITSET save1 = si_opt_1;
  if(reduction == 0)
  {
    si_opt_1 &= (~Sy_bit(OPT_REDSB)); // no reduced Groebner basis
    si_opt_1 &= (~Sy_bit(OPT_REDTAIL)); // not tail reductions
  }
  Set_Error(FALSE);
  Overflow_Error = FALSE;
  //BOOLEAN endwalks = FALSE;
#ifdef TIME_TEST
  clock_t tinput, tostd, tif=0, tstd=0, tlift=0, tred=0, tnw=0;
  xtif=0; xtstd=0; xtlift=0; xtred=0; xtnw=0;
  tinput = clock();
  clock_t tim;
#endif
  nstep=0;
  int i,nwalk;
  int nV = baseRing->N;

  ideal Gomega, M, F, FF, Gomega1, Gomega2, M1;
  ring newRing;
  ring XXRing = baseRing;
  ring targetRing;
  intvec* ivNull = new intvec(nV);
  intvec* curr_weight = new intvec(nV);
  intvec* target_weight = new intvec(nV);
  intvec* exivlp = Mivlp(nV);
/*
  intvec* tmp_weight = new intvec(nV);
  for(i=0; i<nV; i++)
  {
    (*tmp_weight)[i] = (*orig_M)[i];
  }
*/
  for(i=0; i<nV; i++)
  {
    (*curr_weight)[i] = (*orig_M)[i];
    (*target_weight)[i] = (*target_M)[i];
  }
#ifndef BUCHBERGER_ALG
  intvec* hilb_func;
   // to avoid (1,0,...,0) as the target vector
  intvec* last_omega = new intvec(nV);
  for(i=nV-1; i>0; i--)
  {
    (*last_omega)[i] = 1;
  }
  (*last_omega)[0] = 10000;
#endif
  rComplete(currRing);
#ifdef CHECK_IDEAL_MWALK
  if(printout > 2)
  {
    idString(Go,"//** Mwalk: Go");