code: # Copyright 2018 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.
  
  # On-device arrays.
  
  from functools import partial, partialmethod
  import operator
  from typing import (Any, List, Optional, Union)
  import weakref
  
  import numpy as np
  
  from jax import core
  from jax._src.config import config
  from jax._src import abstract_arrays
  from jax._src import dtypes
  from jax._src import profiler
  from jax._src.lib import xla_client as xc
  import jax._src.util as util
  
  ### device-persistent data
  
  xe = xc._xla
  
  Device = xc.Device
  Buffer = xe.Buffer
  
  
  def _forward_method(attrname, self, fun, *args):
    return fun(getattr(self, attrname), *args)
  _forward_to_value = partial(_forward_method, "_value")
  
  
  # The following is used for the type xc.Buffer or _DeviceArray.
  DeviceArrayProtocol = Any
  DeviceArray = xc.DeviceArrayBase
  
  
  def make_device_array(
      aval: core.ShapedArray,
      device: Optional[Device],
      device_buffer: Buffer,
  ) -> Union[Buffer, "_DeviceArray"]:
    """Returns a DeviceArray implementation based on arguments.
  
    This is to be used only within JAX. It will return either a PythonDeviceArray
    or a C++ equivalent implementation.
    """
    if isinstance(device_buffer, xc.Buffer):
  
      if device_buffer.aval == aval and device_buffer._device == device:
        return device_buffer
      device_buffer = device_buffer.clone()
      device_buffer._device = device
      device_buffer.aval = aval
      device_buffer.weak_type = aval.weak_type
      return device_buffer
  
    return _DeviceArray(aval, device, device_buffer)
  
  
  def type_is_device_array(x):
    """Returns `True` if `x` is a non-sharded DeviceArray.
  
    Use this function instead of `type(x) is Devicearray`.
    """
    type_x = type(x)
    return type_x is _DeviceArray or type_x is xc.Buffer
  
  
  def device_array_supports_weakrefs():
    try:
      weakref.ref(DeviceArray())
      return True
    except TypeError:
      return False
  
  
  class _DeviceArray(DeviceArray):  # type: ignore
    """A DeviceArray is an ndarray backed by a single device memory buffer."""
    # We don't subclass ndarray because that would open up a host of issues,
    # but lax_numpy.py overrides isinstance behavior and attaches ndarray methods.
    __slots__ = [
        "aval", "device_buffer", "_npy_value", "_device", "__weakref__"
    ]
    __array_priority__ = 100
  
    # DeviceArray has methods that are dynamically populated in lax_numpy.py,
    # and this annotation is needed to make pytype happy.
    _HAS_DYNAMIC_ATTRIBUTES = True
  
    def __init__(self, aval: core.ShapedArray, device: Optional[Device],
                 device_buffer: Buffer):
      """Initializer.
  
      Args:
        aval: The abstract value associated to this array (shape+dtype+weak_type).
        device:  The optional sticky device. See
          https://jax.readthedocs.io/en/latest/faq.html#controlling-data-and-computation-placement-on-devices
        device_buffer: The underlying buffer owning the on-device data.
      """
      DeviceArray.__init__(self)
      self.aval = aval
      self.device_buffer = device_buffer
      self._device = device
  
      self._npy_value = None
      if config.jax_enable_checks:
        assert type(aval) is core.ShapedArray
        npy_value = self._value
        assert npy_value.dtype == aval.dtype and npy_value.shape == aval.shape, (
            aval, npy_value.shape, npy_value.dtype)
        assert (device is None) or device is device_buffer.device()
  
    def _check_if_deleted(self):
      if self.device_buffer is deleted_buffer:
        raise RuntimeError("DeviceArray has been deleted.")
  
    @profiler.annotate_function
    def block_until_ready(self):
      """Blocks the caller until the buffer's value has been computed on device.
  
      This method is mostly useful for timing microbenchmarks that wish to
      time how long a computation takes, without transferring the result back
      to the host.
  
      Returns the buffer object (`self`).
      """
      self._check_if_deleted()
      self.device_buffer.block_host_until_ready()  # pytype: disable=attribute-error
      return self
  
    @property
    def _value(self):
      self._check_if_deleted()
      if self._npy_value is None:
        self._npy_value = self.device_buffer.to_py()  # pytype: disable=attribute-error  # bind-properties
        self._npy_value.flags.writeable = False
      return self._npy_value
  
    @property
    def shape(self):
      return self.aval.shape
  
    @property
    def dtype(self):
      return self.aval.dtype
  
    @property
    def size(self):
      return util.prod(self.aval.shape)
  
    @property
    def ndim(self):
      return len(self.aval.shape)
  
    def device(self):
      self._check_if_deleted()
      return self.device_buffer.device()  # pytype: disable=attribute-error
  
    def copy_to_host_async(self):
      """Requests a copy of the buffer to the host."""
      self._check_if_deleted()
      if self._npy_value is None:
        self.device_buffer.copy_to_host_async()  # pytype: disable=attribute-error
  
    def delete(self):
      """Deletes the device array and any cached copy on the host.
  
      It is an error to access the contents of a `DeviceArray` after it has
      been deleted.
  
      Use of this method is optional; device buffers will be reclaimed
      automatically by Python when a DeviceArray object is garbage collected.
      However, it is sometimes useful to have more explicit control over the
      time of deletion.
      """
      self.device_buffer.delete()  # pytype: disable=attribute-error
      self.device_buffer = deleted_buffer
      self._npy_value = None
  
    @property
    def __cuda_array_interface__(self):
      return self.device_buffer.__cuda_array_interface__  # pytype: disable=attribute-error  # bind-properties
  
  
  # Adding methods dynamically to both _DeviceArray and xc.Buffer
  # pylint: disable=protected-access
  for device_array in [DeviceArray]:
  
  
    def copy(self):
      """Returns an ndarray (backed by host memory, not device memory)."""
      return np.asarray(self)
    setattr(device_array, "copy", copy)
  
    def __repr__(self):
      line_width = np.get_printoptions()["linewidth"]
      prefix = '{}('.format(self.__class__.__name__.lstrip('_'))
      s = np.array2string(self._value, prefix=prefix, suffix=',',
                          separator=', ', max_line_width=line_width)
      if self.aval is not None and self.aval.weak_type:
        dtype_str = f'dtype={self.dtype.name}, weak_type=True)'
      else:
        dtype_str = f'dtype={self.dtype.name})'
      last_line_len = len(s) - s.rfind('\n') + 1
      sep = ' '
      if last_line_len + len(dtype_str) + 1 > line_width:
        sep = ' ' * len(prefix)
      return "{}{},{}{}".format(prefix, s, sep, dtype_str)
  
    setattr(device_array, "__repr__", __repr__)
  
    def item(self):
      if dtypes.issubdtype(self.dtype, np.complexfloating):
        return complex(self)
      elif dtypes.issubdtype(self.dtype, np.floating):
        return float(self)
      elif dtypes.issubdtype(self.dtype, np.integer):
        return int(self)
      elif dtypes.issubdtype(self.dtype, np.bool_):
        return bool(self)
      else:
        raise TypeError(self.dtype)
  
    setattr(device_array, "item", item)
  
    def __len__(self):
      try:
        return self.aval.shape[0]
      except IndexError as err:
        raise TypeError("len() of unsized object") from err  # same as numpy error
  
    setattr(device_array, "__len__", __len__)
  
    def __iter__(self):
      if self.ndim == 0:
        raise TypeError("iteration over a 0-d array")  # same as numpy error
      else:
        return (sl for chunk in self._chunk_iter(100) for sl in chunk._unstack())
  
    setattr(device_array, "__iter__", __iter__)
  
    def __reversed__(self):
      return iter(self[::-1])
  
    setattr(device_array, "__reversed__", __reversed__)
  
    def __format__(self, format_spec):
      # Simulates behavior of https://github.com/numpy/numpy/pull/9883
      if self.ndim == 0:
        return format(self._value[()], format_spec)
      else:
        return format(self._value, format_spec)
  
    setattr(device_array, "__format__", __format__)
  
    def __array__(self, dtype=None, context=None):
      return np.asarray(self._value, dtype=dtype)
  
    setattr(device_array, "__array__", __array__)
  
    setattr(device_array, "__str__", partialmethod(_forward_to_value, str))
    setattr(device_array, "__bool__", partialmethod(_forward_to_value, bool))
    setattr(device_array, "__nonzero__", partialmethod(_forward_to_value, bool))
    setattr(device_array, "__float__", lambda self: self._value.__float__())
    setattr(device_array, "__int__", lambda self: self._value.__int__())
    setattr(device_array, "__complex__", lambda self: self._value.__complex__())
    setattr(device_array, "__hex__", partialmethod(_forward_to_value, hex))
    setattr(device_array, "__oct__", partialmethod(_forward_to_value, oct))
    setattr(device_array, "__index__", partialmethod(_forward_to_value,
                                                     operator.index))
    to_bytes = lambda self, order="C": self._value.tobytes(order)
    setattr(device_array, "tobytes", to_bytes)
    del to_bytes
    setattr(device_array, "tolist", lambda self: self._value.tolist())
  
    # pickle saves and loads just like an ndarray
    setattr(device_array, "__reduce__",
            partialmethod(_forward_to_value, operator.methodcaller("__reduce__")))
  
    # explicitly set to be unhashable.
    setattr(device_array, "__hash__", None)
  
    # clobbered when jax.numpy is imported, but useful in tests
    setattr(device_array, "__eq__", lambda self, other: self._value == other)
  
    # The following methods are dynamically overridden in lax_numpy.py.
    def raise_not_implemented():
      raise NotImplementedError
  
    setattr(device_array, "__getitem__", lambda self, i: raise_not_implemented())
  # pylint: enable=protected-access
  
  
  class DeletedBuffer(object): pass
  deleted_buffer = DeletedBuffer()
  
  
  device_array_types: List[type] = [xc.Buffer, _DeviceArray]
  for _device_array in device_array_types:
    core.literalable_types.add(_device_array)
    core.pytype_aval_mappings[device_array] = abstract_arrays.canonical_concrete_aval
  
apis: numpy.get_printoptions numpy.asarray numpy.array2string