mult()

ring_elem SchurRing2::mult ( const ring_elem f, const ring_elem g ) const

virtual

Implements Ring.

Reimplemented in SchurSnRing.

Definition at line 616 of file schur2.cpp.

{
  ring_elem resultRE;
  const schur_poly *f1 = f.get_schur_poly();
  const schur_poly *g1 = g.get_schur_poly();
  ring_elem a;
  if (get_scalar(f1, a))
    {
      return ring_elem(mult_by_coefficient(a, g1));
      // In this case, do a simple multiplication
    }
  else if (get_scalar(g1, a))
    {
      return ring_elem(mult_by_coefficient(a, f1));
    }
  else
    {
      // use the poly heap
      schur_poly_heap H(this);
      for (schur_poly::iterator i = f1->begin(); i != f1->end(); ++i)
        for (schur_poly::iterator j = g1->begin(); j != g1->end(); ++j)
          {
            ring_elem c =
                coefficientRing->mult(i.getCoefficient(), j.getCoefficient());
            ring_elem r = const_cast<SchurRing2 *>(this)->mult_terms(
                i.getMonomial(), j.getMonomial());
            H.add(ring_elem(mult_by_coefficient(c, r.get_schur_poly())));
          }
      return H.value();
    }
}

References schur_poly_heap::add(), schur_poly::begin(), coefficientRing, schur_poly::end(), get_scalar(), ring_elem::get_schur_poly(), mult_by_coefficient(), mult_terms(), SchurRing2(), and schur_poly_heap::value().

Referenced by SchurSnRing::mult(), and SchurSnRing::tensor_mult().