> Monte-Carlo can and should be deterministic and repeatable
I guess it can be made so, but not necessarily easy / fast (if it's parallel, and sensitive to floating point rounding). And sounds like the kind of engineering effort GP is saying isn't worth it. Re-running exactly the same monte-carlo chain does tell you something, but is perhaps the wrong level to be checking. Re-running from a different seed, and getting results that are within error, might be much more useful.
I guess the best thing would be that it uses a different random seed every time it's run (so that, when re-running the code you'll see similar results which verifies that the result is not sensitive to the seed), but the particular seed that produced the particular results published in a paper is noted.
But still, for code running on different machines, especially for numeric-heavy code that might be running on a particular GPU setup, distributed big data source (where you pull the first available data rather than read in a fixed order), or even on some special supercomputer, it's hard to ask that it be totally reproducible down to the smallest rounding error.
I guess it can be made so, but not necessarily easy / fast (if it's parallel, and sensitive to floating point rounding). And sounds like the kind of engineering effort GP is saying isn't worth it. Re-running exactly the same monte-carlo chain does tell you something, but is perhaps the wrong level to be checking. Re-running from a different seed, and getting results that are within error, might be much more useful.