Originally, when these were written, they simply used the naive strategy of "upcast all inputs to floats, and downcast all inputs back". In addition to being... not quite what the kernels did, they also didn't capture some additional semantics. Namely, that the norms (except for layer norm on CPU! cc: @ngimel) return fp32 for the mean and rstd values.
Also, folks didn't like that I wrote `native_layer_norm` in terms of `native_batch_norm`. Which is fair - so I refactored the common logic into a `normalize` function.
cc: @jansel / @bertmaher , who've been looking at lowering layer norm/batch norm.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/77407
Approved by: https://github.com/bertmaher
This makes prims look as if they were defined in native_functions.yaml
but they're still all written in Python. You now need to give a full
schema string for your prims. The returned prim object is now
torch.ops.prim overload (prims are not allowed to be overloaded,
so we return the overload, not the overload packet, for speed.)
Signed-off-by: Edward Z. Yang <ezyangfb.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/77117
Approved by: https://github.com/mruberry, https://github.com/albanD
For the most part, PrimTorch refs have the same signature as their
ATen equivalents. I modify most PrimTorch refs to register themselves
as decompositions, using the prim name they wrap to find the aten name
(except for a few cases where the prim/aten names mismatch). There are
some exclusions, falling into one of two categories:
- The torch equivalent was already implemented as a CompositeImplicitAutograd
decomposition in C++
- The ref doesn't support enough features (e.g., the real deal has more
kwargs / overloads than are currently implemented)
PrimTorch refs are written as a single function that supports all
overloads, and this style is convenient for cases where we have a bundle
of overloads for what morally is a single overload with a Union type
on an argument (which we ought to have supported in
native_functions.yaml but blah); to support registering a single decomp
for all the overloads, we modify register_decomposition to register
to ALL overloads if you pass it an overload packet. This is technically
BC breaking but no tests started failing because of it.
Signed-off-by: Edward Z. Yang <ezyangfb.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/76835
Approved by: https://github.com/Chillee, https://github.com/mruberry
