I hope this is the right place to ask this question.

I was generating prior-predictive samples to assess the appropriateness of different prior specifications and decided to include a specification that has what one might consider diffuse/uninformative priors (e.g., a very wide normal prior). When I compared the prior-predictive samples across operating systems (Linux, Windows, MacOS), I noticed that they were different!

This difference does not occur when I generate prior-predictive samples based on more informative priors. The results are also the equivalent across OSs if I estimate a â€śregularâ€ť model with the data included to get posterior samples (even with the diffuse priors).

I made sure that the same version of R and rstan were used on each OS. I also used the same seed (using set.seed() and the seed argument in the sampling() function). I wonder if there is some inherent difference in how seeds are treated by different operating systems? Or if these differences might be related to how models are compiled across different OSs? Iâ€™m hoping that someone who knows more about these things can help me understand whatâ€™s happening? Any input would be much appreciated :)

Thank you!