public static XMVector Ln(XMVector q)
{
XMVector oneMinusEpsilon = XMVector.FromFloat(1.0f - 0.00001f, 1.0f - 0.00001f, 1.0f - 0.00001f, 1.0f - 0.00001f);
XMVector qw = XMVector.SplatW(q);
XMVector q0 = XMVector.Select(XMGlobalConstants.Select1110, q, XMGlobalConstants.Select1110);
XMVector controlW = qw.InBounds(oneMinusEpsilon);
XMVector theta = qw.ACos();
XMVector sinTheta = theta.Sin();
XMVector s = XMVector.Divide(theta, sinTheta);
XMVector result = XMVector.Multiply(q0, s);
result = XMVector.Select(q0, result, controlW);
return(result);
}