reduce_kk()

bool gbA::reduce_kk ( spair * p )

private

Definition at line 1359 of file gb-default.cpp.

{
  /* Returns false iff we defer computing this spair. */
  /* If false is returned, this routine has grabbed the spair 'p'. */
  int tmf, wt;
  int count = -1;
 
  exponents_t EXP = ALLOCATE_EXPONENTS(exp_size);
 
  if (M2_gbTrace == 15)
    {
      buffer o;
      o << "considering ";
      spair_text_out(o, p);
      o << " : ";
      emit_line(o.str());
    }
  compute_s_pair(p); /* Changes the type, possibly */
 
  while (!R->gbvector_is_zero(p->f()))
    {
      if (count++ > max_reduction_count)
        {
          spair_set_defer(p);
          return false;
        }
      if (M2_gbTrace >= 5)
        {
          if ((wt = weightInfo_->gbvector_weight(p->f(), tmf)) > this_degree)
            {
              buffer o;
              o << "ERROR: degree of polynomial is too high: deg " << wt
                << " termwt " << tmf << " expectedeg " << this_degree
                << newline;
              emit(o.str());
            }
        }
 
      int gap, w;
      R->gbvector_get_lead_exponents(_F, p->f(), EXP);
      int x = p->f()->comp;
      w = find_good_divisor(EXP, x, this_degree, gap);
 
      // replaced gap, g.
      if (w < 0) break;
      if (gap > 0)
        {
          POLY h;
          h.f = R->gbvector_copy(p->x.f.f);
          h.fsyz = R->gbvector_copy(p->x.f.fsyz);
          insert_gb(h, (p->type == SPAIR::SPAIR_GEN ? ELEM_MINGEN : 0));
        }
      POLY g = gb[w]->g;
 
      R->gbvector_reduce_lead_term(_F,
                                   _Fsyz,
                                   nullptr,
                                   p->f(),
                                   p->fsyz(), /* modifies these */
                                   g.f,
                                   g.fsyz);
 
      stats_nreductions++;
      if (M2_gbTrace == 15)
        {
          buffer o;
          o << "    reducing by g" << w;
          o << ", yielding ";
          R->gbvector_text_out(o, _F, p->f(), 3);
          emit_line(o.str());
        }
      if (R->gbvector_is_zero(p->f())) break;
      if (gap > 0)
        {
          p->deg += gap;
          if (M2_gbTrace == 15)
            {
              buffer o;
              o << "    deferring to degree " << p->deg;
              emit_line(o.str());
            }
          spair_set_insert(p);
          return false;
        }
    }
  if (M2_gbTrace >= 4 && M2_gbTrace != 15)
    {
      buffer o;
      o << "." << count;
      emit_wrapped(o.str());
    }
  return true;
}

References _F, _Fsyz, ALLOCATE_EXPONENTS, compute_s_pair(), ELEM_MINGEN, emit(), emit_line(), emit_wrapped(), exp_size, POLY::f, find_good_divisor(), POLY::fsyz, gb(), insert_gb(), M2_gbTrace, max_reduction_count, newline, p, POLY, R, SPAIR_GEN, spair_set_defer(), spair_set_insert(), spair_text_out(), stats_nreductions, buffer::str(), this_degree, weightInfo_, and x.

Referenced by reduceit().