step()

int hilb_comp::step ( )

private

Definition at line 446 of file hilb.cpp.

{
  nsteps++;
  if (current->i == current->first_sum)
    {
      current->h0 = current->h1;
      current->h1 = R->from_long(1);
    }
  if (current->i >= 0)
    {
      // If the i th monomial ideal is a 'special case', simply compute its
      // value
      // Otherwise, find pivot, and quotient/sum creating next level down
      // (possibly make new hilb_step, and increment max_depth if needed)
      // and set current = current->down
      do_ideal(current->monids[current->i]);  // consumes this monomial ideal
    }
  else
    {
      // At this point, all Hilbert functions at this level have been
      // computed, so add the values, and place one step up
      R->add_to(current->h0, current->h1);
      ring_elem f = current->h0;
      current->h0 = R->from_long(0);
      current->h1 = R->from_long(0);
      current->monids.clear();
      if (current->up == nullptr)
        {
          if (input_mat)
            {
              ring_elem tmp =
                  R->make_flat_term(one, input_mat->rows()->degree(this_comp));
              R->mult_to(f, tmp);
              R->remove(tmp);
            }
          R->add_to(result_poincare, f);
          this_comp++;
 
          // Now check if we have any more components
          if (this_comp >= n_components) return COMP_DONE;
          // otherwise go on to the next component:
 
          next_monideal();
          return COMP_COMPUTING;
        }
      current = current->up;
      R->mult_to(current->h1, f);
      current->i--;
      R->remove(f);
    }
  return COMP_COMPUTING;
}

References COMP_COMPUTING, COMP_DONE, current, do_ideal(), input_mat, n_components, next_monideal(), nsteps, one, R, result_poincare, and this_comp.

Referenced by calc().