rawRingElementCRA()

const RingElement * rawRingElementCRA	(	const RingElement *	f,
		const RingElement *	g,
		mpz_srcptr	m,
		mpz_srcptr	n )

Chinese remainder and rational reconstruction interface routines

Definition at line 14 of file cra.cpp.

{
  // Assumption: f and g are either in ZZ, or in a polynomial ring whose coeff
  // ring is ZZ.  The output is a ring element in the same ring.
 
  const Ring *Rf = f->get_ring();
  const Ring *Rg = g->get_ring();
  if (Rf != Rg)
    {
      ERROR("expected same ring");
      return nullptr;
    }
  const PolyRing *P = Rf->cast_to_PolyRing();
  if (P == nullptr)
    {
      // check whether Rf is ZZ.  If not, error.
      if (!Rf->is_ZZ())
        {
          ERROR("expected ZZ, or polynomial ring over ZZ");
          return nullptr;
        }
      ERROR("not implemented yet");
      return nullptr;
    }
  else
    {
      const Ring *K = P->getCoefficientRing();
      if (K->is_ZZ())
        {
          ring_elem rf = f->get_value();
          ring_elem rg = g->get_value();
          ring_elem result = ChineseRemainder::CRA(P, rf, rg, m, n);
          return RingElement::make_raw(Rf, result);
        }
      else
        {
          ERROR("expected coefficient ring to be ZZ");
          return nullptr;
        }
    }
  ERROR("not written yet");
  return nullptr;
}

References Ring::cast_to_PolyRing(), ChineseRemainder::CRA(), ERROR, RingElement::get_ring(), RingElement::get_value(), PolynomialRing::getCoefficientRing(), Ring::is_ZZ(), RingElement::make_raw(), and result().