promote()

bool SchurRing2::promote ( const Ring * R, const ring_elem f, ring_elem & result ) const

virtual

Implements Ring.

Definition at line 431 of file schur2.cpp.

{
  // Cases:
  // 1.  Rf is ZZ
  // 2. Rf is coefficientRing
  // 3. Rf is another SchurRing2
 
  if (Rf == globalZZ)
    {
      from_coeff(Rf->promote(globalZZ, f, result));
      return true;
    }
  else if (Rf == coefficientRing)
    {
      result = from_coeff(f);
      return true;
    }
  else
    {
      const SchurRing2 *Sf = Rf->cast_to_SchurRing2();
      if (Sf != nullptr)
        {
          if (coefficientRing == Sf->getCoefficientRing())
            {
              result = truncate(f);
              return true;
            }
 
          return promote_coeffs(Sf, f, result);
        }
    }
  return false;
}

References Ring::cast_to_SchurRing2(), coefficientRing, from_coeff(), getCoefficientRing(), globalZZ, Ring::promote(), promote_coeffs(), result(), Ring::Ring(), SchurRing2(), and truncate().