new_pairs()

void GBKernelComputation::new_pairs ( int i )

private

Definition at line 184 of file Eschreyer.cpp.

{
  gc_vector<Bag*> elems;
  gc_vector<int> vp;  // This is 'p'.
  gc_vector<int> thisvp;
 
  if (SF)
    {
      monomial PAIRS_mon = ALLOCATE_MONOMIAL(monom_size);
      SF->schreyer_down(gb[i]->monom, gb[i]->comp - 1, PAIRS_mon);
      M->to_varpower(PAIRS_mon, vp);
    }
  else
    M->to_varpower(gb[i]->monom, vp);
 
  // First add in syzygies arising from exterior variables
  // At the moment, there are none of this sort.
 
  if (R->is_skew_commutative())
    {
      exponents_t find_pairs_exp = newarray_atomic(int, M->n_vars());
 
      varpower::to_expvector(M->n_vars(), vp.data(), find_pairs_exp);
      for (int w = 0; w < R->n_skew_commutative_vars(); w++)
        if (find_pairs_exp[R->skew_variable(w)] > 0)
          {
            thisvp.resize(0);
            varpower::var(w, 1, thisvp);
            Bag *b = new Bag(static_cast<void *>(nullptr), thisvp);
            elems.push_back(b);
          }
 
      freemem(find_pairs_exp);
    }
 
  // Second, add in syzygies arising from the base ring, if any
  // The baggage of each of these is NULL
  if (R->is_quotient_ring())
    {
      const MonomialIdeal *Rideal = R->get_quotient_monomials();
      for (Bag& a : *Rideal)
        {
          // Compute (P->quotient_ideal->monom : p->monom)
          // and place this into a varpower and Bag, placing
          // that into 'elems'
          thisvp.resize(0);
          varpower::quotient(a.monom().data(), vp.data(), thisvp);
          if (varpower::is_equal(a.monom().data(), thisvp.data()))
            continue;
          Bag *b = new Bag(static_cast<void *>(nullptr), thisvp);
          elems.push_back(b);
        }
    }
 
  // Third, add in syzygies arising from previous elements of this same level
  // The baggage of each of these is their corresponding res2_pair
 
  MonomialIdeal *mi_orig = mi[gb[i]->comp - 1];
  for (Bag& a : *mi_orig)
    {
      Bag *b = new Bag();
      varpower::quotient(a.monom().data(), vp.data(), b->monom());
      elems.push_back(b);
    }
 
  // Make this monomial ideal, and then run through each minimal generator
  // and insert into the proper degree. (Notice that sorting does not
  // need to be done yet: only once that degree is about to begin.
 
  mi_orig->insert_minimal(new Bag(i, vp));
 
  MonomialIdeal *new_mi = new MonomialIdeal(R, elems);
 
  monomial m = M->make_one();
  for (Bag& a : *new_mi)
    {
      M->from_varpower(a.monom().data(), m);
      M->mult(m, gb[i]->monom, m);
 
      gbvector *q = make_syz_term(
          GR->get_flattened_coefficients()->from_long(1), m, i + 1);
      syzygies.push_back(q);
    }
}

References ALLOCATE_MONOMIAL, freemem(), gb, GR, MonomialIdeal::insert_minimal(), ExponentList< int, true >::is_equal(), M, make_syz_term(), mi, int_bag::monom(), monom_size, monomial, newarray_atomic, ExponentList< int, true >::quotient(), R, SF, syzygies, ExponentList< int, true >::to_expvector(), and ExponentList< int, true >::var().

Referenced by calc().