# Objective
Different platforms use their own implementations of several
mathematical functions (especially transcendental functions like sin,
cos, tan, atan, and so on) to provide hardware-level optimization using
intrinsics. This is good for performance, but bad when you expect
consistent outputs across machines.
[`libm`](https://github.com/rust-lang/libm) is a widely used crate that
provides mathematical functions that don't use intrinsics like `std`
functions. This allows bit-for-bit deterministic math across hardware,
which is crucial for things like cross-platform deterministic physics
simulation.
Glam has the `libm` feature for using [`libm` for the
math](d2871a151b/src/f32/math.rs (L35))
in its own types. This would be nice to expose as a feature in
`bevy_math`.
## Solution
Add `libm` feature to `bevy_math`. We could name it something like
`enhanced-determinism`, but this wouldn't be accurate for the rest of
Bevy, so I think just `libm` is more fitting and explicit.
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