Cross Platform Derminism

[spindizzyio]

Is this .js version also cross platform deterministic?

[jrouwe]

It is cross platform deterministic if you build it yourself using:

./build.sh Distribution -DCROSS_PLATFORM_DETERMINISTIC=ON

This is verified in CI here running with nodejs on Linux and comparing it with the C++ version across all other supported platforms.

There are a number of caveats though:

• I haven't tested if all browsers produce the same hash, there may be differences in their WASM implementation
• This only tests if the library is deterministic, I don't know if JavaScript itself is deterministic across platforms/browsers. For example, in C++ the sin() function is different between platforms and similar things may be present in the JavaScript libraries. Take a look at the Jolt documentation for other things that were an issue in the C++ standard libraries.

[LeXXik]

I don't know if JavaScript itself is deterministic across platforms/browsers.

Trigonometry functions, like sin/cos are non-deterministic in JS. I mean JS Math.sin, Math.cos, etc. JS VM will use browser implementation and will produce different results depending on browser/cpu. WebAssembly doesn't provide those either, so the compilers tend to add a math library. In this case we deal with emscripten, which has libm included, so the math will be deterministic when using Wasm:
https://github.com/emscripten-core/emscripten/blob/main/system/lib/libc/musl/src/internal/libm.h