get_betti()

M2_arrayint res_comp::get_betti ( int type ) const

virtual

Implements ResolutionComputation.

Definition at line 1179 of file res-a1.cpp.

{
  int lo = low_degree();
  int hi = high_degree();
  int len = (type == 0 ? length_limit : max_level());
 
  int *bettis;
  betti_init(lo, hi, len, bettis);
 
  for (int d = lo; d <= hi; d++)
    for (int lev = 0; lev <= len; lev++)
      {
        int val = 0;
        switch (type)
          {
            case 0:
              val = n_minimal(lev, d);
              break;
            case 1:
              val = n_pairs(lev, d);
              break;
            case 2:
              val = n_left(lev, d);
              break;
            case 3:
              val = n_monoms(lev, d);
              break;
            case 4:
              ERROR(
                  "cannot use Minimize=>true unless "
                  "res(...,FastNonminimal=>true) was used");
              return nullptr;
            default:
              val = -1;
              break;
          }
        bettis[lev + (len + 1) * (d - lo)] = val;
      }
 
  M2_arrayint result = betti_make(lo, hi, len, bettis);
  freemem(bettis);
  return result;
}

References ResolutionComputation::betti_init(), ResolutionComputation::betti_make(), ERROR, freemem(), high_degree(), length_limit, low_degree(), max_level(), n_left(), n_minimal(), n_monoms(), n_pairs(), and result().

Referenced by betti_minimal(), betti_nmonoms(), betti_remaining(), and betti_skeleton().