> Does scientific-grade code need to be reproducible? Yes. Fundamentally yes. The reproducibility of results is core to the scientific method. Yes, that include

> Does scientific-grade code need to be reproducible? Yes. Fundamentally yes. The reproducibility of results is core to the scientific method. Yes, that includes Monte Carlo code, [...] Reproducibility in the scientific sense is different from running the same program with the same input, and getting exactly the same result. Repreducibility means that if you repeat the measurements in another environment, getting somewhat different data, and apply the same theory and methods, you get to the same conclusion. The property of a computer program that when you run it again with the same input, you get the same output, is nice and very helpful for debugging. But the fact that you can run the same program does not mean that it is bug-free, as much as the fact that you can copy a paper with a mathematical proof does not mean that the proof is correct. Also, multi-threaded and parallel code is inherently non-deterministic. > when there is no such thing as truly random number generation on contemporary computers, only pseudorandom number generation, That is wrong. Linux for example uses latency measurements from drivers such as HDD drive seek latencies or keyboards to generate entropy. While it might not the best thing to rely on for purposes of cryptography, it is surely not deterministic. If it would matter, you could download real-time astronomical noise measurements and use them to seed your Mersenne Twister generator.