Transferring an array from host to device on CPU sometimes does a zero-copy implementation where no memory is actually moved. This is now never done with int4, since int4 arrays are stored in packed format on device and an unpacked format on host. Similarly, transferring an array from device to host on CPU used to always use a zero-copy implementation, but now it will unpack and copy for int4 arrays.
PiperOrigin-RevId: 578692796
The motivation here is to gradually replace all dynamic lookups on `jax.config`
with statically-typed state objects, which are more type checker/IDE friendly.
PiperOrigin-RevId: 571932143
This flag only exists for the use of JAX's own tests, and doesn't need to exist for most JAX users.
4f805c2d8f allows this move since none of the test comparison utilities now depend on the choice of backend. (That dependency was only an administrative dependency for external users of JAX, since the only public users of the test comparison utilites are the gradient utilities, which always override the default tolerance with their own tolerances.)
PiperOrigin-RevId: 563195002
In cases where this causes TPU tests to fail, relax test tolerances in the test cases themselves.
TPUs are less precise only for specific operations, notably matrix multiplication (for which usually enabling higher-precision matrix multiplication is the right choice if precision is needed), and certain special functions (e.g., log/exp/pow).
The net effect of this change is mostly to tighten up many test tolerances on TPU.
PiperOrigin-RevId: 562953488
Change flags to use the newer definition style where the flag is read via a typed FlagHolder object returned by the DEFINE_... function. The advantage of doing this is that `flag.value` has a type known to the type checker, rather than reading it as an attr out of a gigantic config dictionary.
For jax.config flags, define a typed FlagHolder object that is returned when defining a flag, matching the ABSL API.
Move a number of flags into the file that consumes them. There's no reason we're defining every flag in `config.py`.
This PR does not change the similar "state" objects in `jax.config`. Changing those is for a future PR.
PiperOrigin-RevId: 551604974
Limit jax._src.lib to shims around jaxlib and nothing else.
The goal of this change is to avoid a dependency cycle between the rest of jax and jax._src.lib in a Bazel build. This allows the types for jax._src.lib to be inferred by pytype in isolation without referring to the rest of JAX.
PiperOrigin-RevId: 512922397
