// Float64Gmp returns the nearest float64 value for z and a bool indicating
// whether f represents z exactly. If the magnitude of z is too large to
// be represented by a float64, f is an infinity and exact is false.
// The sign of f always matches the sign of z, even if f == 0.
//
// NB This uses GMP which is fast but rounds differently to Float64
func (z *Rat) Float64Gmp() (f float64, exact bool) {
z.doinit()
f = float64(C.mpq_get_d(&z.i[0]))
if !(math.IsNaN(f) || math.IsInf(f, 0)) {
exact = new(Rat).SetFloat64(f).Cmp(z) == 0
}
return
}
func (q *Rat) Double() float64 {
q.doinit()
return float64(C.mpq_get_d(&q.i[0]))
}