Function MWalkRandomNextWeight

Singular/walk.cc:4517–4712

* compute a next weight vector * ********************************/

 * compute a next weight vector *
 ********************************/
static intvec* MWalkRandomNextWeight(ideal G, intvec* orig_M, intvec* target_weight,
       int weight_rad, int pert_deg)
{
  assume(currRing != NULL && orig_M != NULL &&
         target_weight != NULL && G->m[0] != NULL);

  //BOOLEAN nError = Overflow_Error;
  Overflow_Error = FALSE;

  BOOLEAN found_random_weight = FALSE;
  int i,nV = currRing->N;
  intvec* curr_weight = new intvec(nV);

  for(i=0; i<nV; i++)
  {
    (*curr_weight)[i] = (*orig_M)[i];
  }

  int k=0,weight_norm;
  intvec* next_weight;
  intvec* next_weight1 = MkInterRedNextWeight(curr_weight,target_weight,G);
  intvec* next_weight2 = new intvec(nV);
  intvec* result = new intvec(nV);
  intvec* curr_weight1;
  ideal G_test, G_test1, G_test2;

  //try to find a random next weight vector "next_weight2"
  if(weight_rad > 0)
  {
    while(k<10)
    {
      weight_norm = 0;
      while(weight_norm == 0)
      {
        for(i=0; i<nV; i++)
        {
          (*next_weight2)[i] = rand() % 60000 - 30000;
          weight_norm = weight_norm + (*next_weight2)[i]*(*next_weight2)[i];
        }
        weight_norm = 1 + static_cast<int>(sqrt(double(weight_norm)));
      }
      for(i=0; i<nV; i++)
      {
        if((*next_weight2)[i] < 0)
        {
          (*next_weight2)[i] = 1 + (*curr_weight)[i] + weight_rad*(*next_weight2)[i]/weight_norm;
        }
        else
        {
          (*next_weight2)[i] = (*curr_weight)[i] + weight_rad*(*next_weight2)[i]/weight_norm;
        }
      }
      if(test_w_in_ConeCC(G,next_weight2) == 1)
      {
        if(maxlengthpoly(MwalkInitialForm(G,next_weight2))<2)
        {
          next_weight2 = MkInterRedNextWeight(next_weight2,target_weight,G);
        }