remainder() [2/2]

void ReducedGB_Field::remainder ( POLY & f, bool use_denom, ring_elem & denom )

virtual

Implements ReducedGB.

Reimplemented in ReducedGB_Field_Local.

Definition at line 111 of file reducedgb-field.cpp.

{
  gbvector head;
  gbvector *frem = &head;
  frem->next = nullptr;
  POLY h = f;
  exponents_t EXP = ALLOCATE_EXPONENTS(R->exponent_byte_size());
 
  while (!R->gbvector_is_zero(h.f))
    {
      R->gbvector_get_lead_exponents(F, h.f, EXP);
      int x = h.f->comp;
      Bag *b;
      if (Rideal != nullptr && Rideal->search_expvector(EXP, b))
        {
          const gbvector *g = originalR->quotient_gbvector(b->basis_elem());
          R->gbvector_reduce_lead_term(
              F, Fsyz, head.next, h.f, h.fsyz, g, nullptr, use_denom, denom);
        }
      else
        {
          int w = T->find_divisor(EXP, x);
          if (w >= 0)
            {
              POLY g = polys[w];
              R->gbvector_reduce_lead_term(F,
                                           Fsyz,
                                           head.next,
                                           h.f,
                                           h.fsyz,
                                           g.f,
                                           g.fsyz,
                                           use_denom,
                                           denom);
            }
          else
            {
              frem->next = h.f;
              frem = frem->next;
              h.f = h.f->next;
              frem->next = nullptr;
            }
        }
    }
  
  h.f = head.next;
 
  ring_elem denom1;
  ring_elem one_elem = R->get_flattened_coefficients()->one();
  denom1 = R->get_flattened_coefficients()->one(); // is replaced on next line
  originalR->get_quotient_info()->gbvector_normal_form(
                                                       Fsyz, h.fsyz, true, denom1);
  if (EQ != R->get_flattened_coefficients()->compare_elems(denom1, one_elem))
    {
      // multiply h.f by denom1.
      R->gbvector_mult_by_coeff_to(h.f, denom1);
    }
  if (use_denom)
    {
      R->get_flattened_coefficients()->mult_to(denom, denom1);
    }
  
  f.f = h.f;
  f.fsyz = h.fsyz;
}

References ALLOCATE_EXPONENTS, int_bag::basis_elem(), gbvector::comp, EQ, ReducedGB::F, POLY::f, ReducedGB::Fsyz, POLY::fsyz, gbvector::next, ReducedGB::originalR, POLY, ReducedGB::R, Rideal, T, and x.

Referenced by minimalize().