rocm_jax/jax/_src/dlpack.py
Peter Hawkins 2469ad1bb3 Cleanups for laziness. No functional changes intended.
Use None as a trivial lazy expression in more places. Simplify some code.
2021-03-07 11:33:04 -05:00

65 lines
2.6 KiB
Python

# Copyright 2020 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from jax import core
from jax import numpy as jnp
from jax.interpreters import xla
from jax.lib import xla_client
from jax.lib import xla_bridge
SUPPORTED_DTYPES = set([jnp.int8, jnp.int16, jnp.int32, jnp.int64,
jnp.uint8, jnp.uint16, jnp.uint32, jnp.uint64,
jnp.float16, jnp.bfloat16, jnp.float32, jnp.float64])
def to_dlpack(x: xla.DeviceArrayProtocol, take_ownership: bool = False):
"""Returns a DLPack tensor that encapsulates a DeviceArray `x`.
Takes ownership of the contents of `x`; leaves `x` in an invalid/deleted
state.
Args:
x: a `DeviceArray`, on either CPU or GPU.
take_ownership: If ``True``, JAX hands ownership of the buffer to DLPack,
and the consumer is free to mutate the buffer; the JAX buffer acts as if
it were deleted. If ``False``, JAX retains ownership of the buffer; it is
undefined behavior if the DLPack consumer writes to a buffer that JAX
owns.
"""
if not isinstance(x, xla.DeviceArray):
raise TypeError("Argument to to_dlpack must be a DeviceArray, got {}"
.format(type(x)))
buf = xla._force(x).device_buffer
return xla_client._xla.buffer_to_dlpack_managed_tensor(
buf, take_ownership=take_ownership)
def from_dlpack(dlpack, backend=None):
"""Returns a `DeviceArray` representation of a DLPack tensor `dlpack`.
The returned `DeviceArray` shares memory with `dlpack`.
Args:
dlpack: a DLPack tensor, on either CPU or GPU.
backend: experimental, optional: the platform on which `dlpack` lives.
"""
# TODO(phawkins): ideally the user wouldn't need to provide a backend and we
# would be able to figure it out from the DLPack.
backend = backend or xla_bridge.get_backend()
client = getattr(backend, "client", backend)
buf = xla_client._xla.dlpack_managed_tensor_to_buffer(dlpack, client)
xla_shape = buf.xla_shape()
assert not xla_shape.is_tuple()
aval = core.ShapedArray(xla_shape.dimensions(), xla_shape.numpy_dtype())
return xla.make_device_array(aval, buf.device(), None, buf) # pytype: disable=attribute-error