reduce_minimal()

void res_comp::reduce_minimal ( int x, resterm *& f, VECTOR(res_pair *)& elems ) const

private

Definition at line 1410 of file res-a1.cpp.

{
  monomial MINIMAL_mon = ALLOCATE_MONOMIAL(monom_size);
 
  // Reduce any components of 'f' that correspond to non minimal syzygies.
  const resterm *tm;
 
  for (int i = x - 1; i >= 0; i--)
    {
      res_pair *p = elems[i];
      if (p->syz_type == SYZ_NOT_MINIMAL)
        while ((tm = R->component_occurs_in(p->pivot_term->comp, f)) != nullptr)
          {
            // Subtract the proper multiple to f.  f = ... + c m e_y + ...
            // and                                 p = ... + d n e_y
            // where n|m.  So we want to compute f -= c/d m/n p.
            ring_elem c =
                K->divide(tm->coeff, p->pivot_term->coeff);  // exact division
            // MES: is the following line actually needed?
            M->divide(tm->monom, p->pivot_term->monom, MINIMAL_mon);
            if (p->stripped_syz == nullptr) p->stripped_syz = R->strip(p->syz);
            R->subtract_multiple_to(f, c, MINIMAL_mon, p->stripped_syz);
          }
    }
}

References ALLOCATE_MONOMIAL, resterm::coeff, K, M, resterm::monom, monom_size, monomial, p, R, SYZ_NOT_MINIMAL, and x.

Referenced by make_minimal().