lower_associate_divisor()

bool M2::RingQQ::lower_associate_divisor ( ring_elem & f, const ring_elem g ) const

inlinevirtual

Reimplemented from Ring.

Definition at line 543 of file aring-glue.hpp.

  {
    mpq_srcptr a = MPQ_VAL(f);
    mpq_srcptr b = MPQ_VAL(g);
    int sa = mpq_sgn(a);
    int sb = mpq_sgn(b);
    int s = (sa == 0 ? sb : sa);
    mpq_ptr result = getmemstructtype(mpq_ptr);
    mpq_init(result);
 
    mpz_gcd(mpq_numref(result), mpq_numref(a), mpq_numref(b));
    mpz_lcm(mpq_denref(result), mpq_denref(a), mpq_denref(b));
    if (s != mpq_sgn(result)) mpq_neg(result, result);
    mpz_reallocate_limbs(mpq_numref(result));
    mpz_reallocate_limbs(mpq_denref(result));
    f = ring_elem(result);
    return true;  // the answer could become lower, if a newer g has a larger
                  // denom
  }

References getmemstructtype, MPQ_VAL, mpz_reallocate_limbs(), result(), and s.