NICE and NICE.jl give different results

[PaulWAyers]

Based on Hasan's tests, NICE and NICE.jl give different results.

We should figure out what's going on. His presentation is Thursday, and I doubt I'll have time to look at it before then. @msricher do you think you could see what's off? @mmg870630 might be helpful too.

Marco, this is a net-event kinetic-Monte-Carlo code we've been working on in the group.

[msricher]

I'd tend to trust the Julia version over the Fortran version, which interfaces with Python and might no longer work properly? They're just ports of the same code otherwise. (Just speculation)

[PaulWAyers]

True. But we need to know why they are different too. I thought it was just that the equilibrium constants were defined in inverse (one used forward, and one used reverse) equilibrium constants. But I'm not sure it is that simple.

[Charlie-1-3]

Different languages and libraries might handle numerical precision differently. Small differences in numerical precision can accumulate over time and lead to divergent results.
Also, both implementations involve randomness in selecting reactions (kmc_select_reaction and nekmc_select_reaction).
Ensure that both implementations use the same random number generation method and seed to obtain consistent results.

[PaulWAyers]

This issue will be resolved when the exact solver is implemented, enabling more tests to be run. As that is a current issue, I'm going to close this and make it a sub-issue of that one.