Function ln

docs/app/js/sanddance-app.js:75146–75155

(out, a)

    return out;
}
function ln(out, a) {
    var x = a[0], y = a[1], z = a[2], w = a[3];
    var r = Math.sqrt(x * x + y * y + z * z);
    var t = r > 0 ? Math.atan2(r, w) / r : 0;
    out[0] = x * t;
    out[1] = y * t;
    out[2] = z * t;
    out[3] = 0.5 * Math.log(x * x + y * y + z * z + w * w);
    return out;
}
function pow(out, a, b) {
    ln(out, a);
    scale(out, out, b);