FP hardware is in this sorry state where they have varying capabilities, but we need to dispel this notion that floating point can't be made deterministic acros

FP hardware is in this sorry state where they have varying capabilities, but we need to dispel this notion that floating point can't be made deterministic across architectures. If it runs on a computer of course it can be made deterministic. Right now it requires some care, but I hope in the future it will be easier. You can absolutely have determinism across different architectures, if you stick with architectures that support IEEE 754-2008. Also if a compiler break determinism this is a serious bug (as long as you don't enable -ffast-math of course - otherwise you're asking for breakage). Unfortunately this means no SIMD, also you need to bring your own transcendental functions (sin, cos, etc). Also you need to be wary of other forms of nondeterminism like threads. There's a physics engine meant for games and robotics called Rapier [0] that has a feature enhanced-determinism that will enable cross-platform determinism (by disabling threads and simd). If you spot any form of nondeterminism, it's absolutely a bug (either on the compiler or on the library itself), just like it would be a bug if it used only integers (which, by the way, was how nphysics, the antecessor of Rapier, implemented determinism: it used fixed-point math with integers [1]) [0] https://rapier.rs/docs/user_guides/rust/determinism/ https://rapier.rs/docs/user_guides/rust/determinism/ - also it has amazing docs [1] https://rustsim.org/blog/2020/06/01/this-month-in-rustsim/#make-nphysics-deterministic-with-fixed-point-numbers https://rustsim.org/blog/2020/06/01/this-month-in-rustsim/#m...