title: How fast is the GLSL "determinant()" function
body: <p>I'm programming a raytracer in GLSL and there are multiple algorithms for calculating the ray-triangle-intersection.
  Some of these are using determinants some not, but the point is that calculating a determinant is slow.
  So my question is : Is the determinant() function optimized on GPUs and how fast is it in comparison with multiplications.</p>