simplify()

void FractionField::simplify ( frac_elem * f ) const

private

Definition at line 108 of file frac.cpp.

{
  ring_elem x, y;
  if (use_gcd_simplify)
    {
      y = f->denom;
      if (R_->is_equal(y, R_->one())) return;
      x = f->numer;
      const RingElement *a = RingElement::make_raw(R_, x);
      const RingElement *b = RingElement::make_raw(R_, y);
      const RingElement *c = rawGCDRingElement(a, b, nullptr, false);
      if (!c) return;
 
#if 0
      // Debugging code
            buffer o;
            o << newline;
            o << "a = ";
            a->text_out(o);
            o << "  b = ";
            b->text_out(o);
            o << " gcd = ";
            c->text_out(o);
            o << newline;
            emit(o.str());
#endif
      if (!R_->is_equal(c->get_value(), R_->one()))
        {
          f->numer = R_->divide(f->numer, c->get_value());
          f->denom = R_->divide(f->denom, c->get_value());
        }
      // Now, let's take the content of the denominator, and divide the
      // numerator
      // and denominator by this value.
      ring_elem ct = R_->content(
          f->denom, f->numer);  // result is in R_->getCoefficients()
 
#if 0
            o.reset();
            o << "f->numer = ";
            R_->elem_text_out(o,f->numer);
            o << "  f->denom = ";
            R_->elem_text_out(o,f->denom);
            o << " ass= ";
            R_->getCoefficients()->elem_text_out(o,ct);
            o << newline;
            emit(o.str());
#endif
 
      if (!R_->getCoefficients()->is_equal(ct, R_->getCoefficients()->one()))
        {
          f->numer = R_->divide_by_given_content(f->numer, ct);
          f->denom = R_->divide_by_given_content(f->denom, ct);
        }
    }
  else
    {
      R_->syzygy(f->numer, f->denom, x, y);
      if (R_->is_zero(x))
        {
          R_->remove(x);
          set_non_unit_frac(f->denom);
          f->numer = R_->zero();
          f->denom = R_->one();
          return;
        }
      R_->negate_to(y);
      R_->remove(f->numer);
      R_->remove(f->denom);
      f->numer = y;
      f->denom = x;
    }
}

References frac_elem::denom, emit(), RingElement::get_value(), RingElement::make_raw(), newline, frac_elem::numer, R_, rawGCDRingElement(), buffer::reset(), set_non_unit_frac(), buffer::str(), RingElement::text_out(), use_gcd_simplify, and x.

Referenced by internal_add_to(), internal_subtract_to(), and make_elem().