I am trying NR Poisson random number generator, (poidev(), on different platforms and I found out that the generator produces different sequences on IBM SP4 and on Sun sprac and SGI Origin 2000 (the later two outcomes are the same). I used XLF90 to compile the codes on SP4 and F90 on Sun sprac and Origin 2000. I have also tried with different optimization options, but it does not affect the sequences. What could be the explainations of this problem?

Forget the question. The problem was caused by an extension in XL Fortran.:rolleyes: