step()

int DetComputation::step

(

)

Definition at line 190 of file det.cpp.

{
  if (done) return COMP_DONE;
 
  ring_elem r;
 
  if (strategy == DET_BAREISS)
    {
      get_minor(row_set, col_set, p, D);
      r = bareiss_det();
    }
  else if (strategy == DET_DYNAMIC)
    {
      if (dynamic_cache.empty())
        {  // Cache minors if needed
          dynamic_cache.resize(p);
          if (make_dynamic_cache() == COMP_INTERRUPTED) return COMP_INTERRUPTED;
        }
      std::vector<int> row_vec(p), col_vec(p);
      for (int i = 0; i < p; ++i)
        {
          row_vec[i] = static_cast<int>(row_set[i]);
          col_vec[i] = static_cast<int>(col_set[i]);
        }
      // Find row number
      const Subdeterminant &map = dynamic_cache[p - 1][row_lookup[row_vec[0]]];
      auto it = map.find({row_vec, col_vec});
      if (it != map.end()) { r = it->second; }
      else { r = ZERO_RINGELEM; }
    }
  else
    r = calc_det(row_set, col_set, p);
 
  if (!R->is_zero(r))
    {
      if (do_exterior)
        result.set_entry(this_row, this_col, r);
      else
        result.append(R->make_vec(0, r));
    }
  else
    R->remove(r);
 
  this_row++;
  if (!Subsets::increment(M->n_rows(), p, row_set))
    {
      // Now we increment column
      if (!Subsets::increment(M->n_cols(), p, col_set))
        {
          done = true;
          return COMP_DONE;
        }
      // Now set the row set back to initial value
      this_col++;
      this_row = 0;
      for (size_t i = 0; i < p; i++) row_set[i] = i;
    }
  return COMP_COMPUTING;
}

References bareiss_det(), calc_det(), col_set, COMP_COMPUTING, COMP_DONE, COMP_INTERRUPTED, D, DET_BAREISS, DET_DYNAMIC, do_exterior, done, dynamic_cache, get_minor(), Subsets::increment(), M, make_dynamic_cache(), p, R, result, row_lookup, row_set, strategy, this_col, this_row, and ZERO_RINGELEM.

Referenced by calc().