betti_make()

M2_arrayint ResolutionComputation::betti_make ( int lo, int hi, int len, int * bettis )

static

Definition at line 157 of file comp-res.cpp.

{
  int d, lev;
  int hi1 = hi + 1;
  int len1 = len + 1;
 
  // Reset 'hi1' to reflect the top degree that occurs
  for (d = hi; d >= lo; d--)
    {
      for (lev = 0; lev <= len; lev++)
        if (bettis[lev + (len + 1) * (d - lo)] > 0)
          {
            hi1 = d;
            break;
          }
      if (hi1 <= hi) break;
    }
  if (hi1 > hi) hi1 = hi;
 
  // Reset 'len1' to reflect the top level that occurs
  for (lev = len; lev >= 0; lev--)
    {
      for (d = lo; d <= hi1; d++)
        if (bettis[lev + (len + 1) * (d - lo)] > 0)
          {
            len1 = lev;
            break;
          }
      if (len1 <= len) break;
    }
  if (len1 > len) len1 = len;
 
  int totallen = (hi1 - lo + 1) * (len1 + 1);
  M2_arrayint result = M2_makearrayint(3 + totallen);
 
  result->array[0] = lo;
  result->array[1] = hi1;
  result->array[2] = len1;
 
  int next = 3;
  for (d = lo; d <= hi1; d++)
    for (lev = 0; lev <= len1; lev++)
      result->array[next++] = bettis[lev + (len + 1) * (d - lo)];
 
  return result;
}

References M2_makearrayint(), and result().

Referenced by gbres_comp::betti_minimal(), res2_comp::betti_minimal(), res2_comp::betti_nmonoms(), res2_comp::betti_remaining(), and res_comp::get_betti().