dlartg function

Implementation

void dlartg(
  final double f,
  final double g,
  final Box<double> c,
  final Box<double> s,
  final Box<double> r,
) {
  final rtmin = sqrt(_safmin);
  final rtmax = sqrt(_safmax / 2);

  final f1 = f.abs();
  final g1 = g.abs();
  if (g == _zero) {
    c.value = _one;
    s.value = _zero;
    r.value = f;
  } else if (f == _zero) {
    c.value = _zero;
    s.value = sign(_one, g);
    r.value = g1;
  } else if (f1 > rtmin && f1 < rtmax && g1 > rtmin && g1 < rtmax) {
    final d = sqrt(f * f + g * g);
    c.value = f1 / d;
    r.value = sign(d, f);
    s.value = g / r.value;
  } else {
    final u = min(_safmax, max(_safmin, max(f1, g1)));
    final fs = f / u;
    final gs = g / u;
    final d = sqrt(fs * fs + gs * gs);
    c.value = fs.abs() / d;
    r.value = sign(d, f);
    s.value = gs / r.value;
    r.value *= u;
  }
}