Rick,
Prior to reading this, I didn't realize recursive codes could be vectorized!!

I converted an MLE optimization code which relied on recursion of the form: S(t) = S(t-1)*h(t-1)*exp(a) as a part of the function module, from loop to vector. The optimization time in IML reduced from 160 seconds to 20 seconds! What's better is the fact that the recursion part was done as a loop within a loop, which now, I can completely convert to vector form.

This is so beautiful, thank you so much!