addScalarMultipleOf()

void FreeAlgebra::addScalarMultipleOf	(	Poly &	result,
		Poly::const_iterator	fBegin,
		Poly::const_iterator	fEnd,
		Poly::const_iterator	gBegin,
		Poly::const_iterator	gEnd,
		ring_elem	coeff ) const

Definition at line 315 of file FreeAlgebra.cpp.

{
  auto& outcoeff = result.getCoeffInserter();
  auto& outmonom = result.getMonomInserter();
  
  // loop over the iterators for f and g, adding the bigger of the two to
  // the back of the monomial and coefficient vectors of the result.  If a tie, add the coefficients.
  while ((fBegin != fEnd) && (gBegin != gEnd))
    {
      auto fMon = fBegin.monom();
      auto gMon = gBegin.monom();
      auto fCoeff = fBegin.coeff();
      auto gCoeff = gBegin.coeff();
      ring_elem coeffResult;
      switch(monoid().compare(fMon,gMon))
        {
        case LT:
          coeffResult = coefficientRing()->mult(coeff,gCoeff);
          if (!coefficientRing()->is_zero(coeffResult))
          {
            outcoeff.push_back(coeffResult);
            monoid().copy(gMon, outmonom);
          }
          gBegin++;
          break;
        case GT:
          outcoeff.push_back(fCoeff);
          monoid().copy(fMon, outmonom);
          fBegin++;
          break;
        case EQ:
          ring_elem tempResult = coefficientRing()->mult(coeff,gCoeff);
          coeffResult = coefficientRing()->add(fCoeff,tempResult);
          if (!coefficientRing()->is_zero(coeffResult))
            {
              outcoeff.push_back(coeffResult);
              monoid().copy(gMon, outmonom);
            }
          fBegin++;
          gBegin++;
        }
    }
  if (fBegin == fEnd)
    {
      for ( ; gBegin != gEnd; gBegin++)
        {
          auto gMon = gBegin.monom();
          auto gCoeff = gBegin.coeff();
          ring_elem coeffResult = coefficientRing()->mult(coeff,gCoeff);
          if (!coefficientRing()->is_zero(coeffResult))
          {
            outcoeff.push_back(coeffResult);
            monoid().copy(gMon, outmonom);
          }
        }
    }
  if (gBegin == gEnd)
    {
      for ( ; fBegin != fEnd; fBegin++)
        {
          auto fMon = fBegin.monom();
          auto fCoeff = fBegin.coeff();
          outcoeff.push_back(fCoeff);
          monoid().copy(fMon, outmonom);
        }
    }
}

References Ring::add(), coefficientRing(), compare(), FreeMonoid::copy(), EQ, GT, is_zero(), LT, monoid(), Ring::mult(), and result().

Referenced by add(), add(), subtract(), and subtractScalarMultipleOf().