Finalize the deprecation of the arr.device() method

The method has been emitting an DeprecationWarning since JAX v0.4.21, released December 2023. Existing uses can be replaced with `arr.devices()` or `arr.sharding`, depending on the context.

PiperOrigin-RevId: 623015500

Author: Jake VanderPlas

CHANGELOG.md

@@ -21,6 +21,8 @@ Remember to align the itemized text with the first line of an item within a list
   * {func}`jax.numpy.clip` has a new argument signature: `a`, `a_min`, and
     `a_max` are deprecated in favor of `x` (positonal only), `min`, and
     `max` ({jax-issue}`20550`).
+  * The `device()` method of JAX arrays has been removed, after being deprecated
+    since JAX v0.4.21. Use `arr.devices()` instead.
 
 
 ## jaxlib 0.4.27

jax/_src/array.py

@@ -30,7 +30,6 @@
 from jax._src import basearray
 from jax._src import config
 from jax._src import core
-from jax._src import deprecations
 from jax._src import dispatch
 from jax._src import dtypes
 from jax._src import errors
@@ -50,7 +49,6 @@
 from jax._src.typing import ArrayLike
 from jax._src.util import safe_zip, unzip3, use_cpp_class, use_cpp_method
 
-deprecations.register(__name__, "device-method")
 
 Shape = tuple[int, ...]
 Device = xc.Device
@@ -471,21 +469,6 @@ def on_device_size_in_bytes(self):
     per_shard_size = arr.on_device_size_in_bytes()  # type: ignore
     return per_shard_size * len(self.sharding.device_set)
 
-  # TODO(yashkatariya): Remove this method when everyone is using devices().
-  def device(self) -> Device:
-    if deprecations.is_accelerated(__name__, "device-method"):
-      raise NotImplementedError("arr.device() is deprecated. Use arr.devices() instead.")
-    else:
-      warnings.warn("arr.device() is deprecated. Use arr.devices() instead.",
-                    DeprecationWarning, stacklevel=2)
-    self._check_if_deleted()
-    device_set = self.sharding.device_set
-    if len(device_set) == 1:
-      single_device, = device_set
-      return single_device
-    raise ValueError('Length of devices is greater than 1. '
-                     'Please use `.devices()`.')
-
   def devices(self) -> set[Device]:
     self._check_if_deleted()
     return self.sharding.device_set

jax/_src/basearray.pyi

@@ -196,7 +196,6 @@ class Array(abc.ABC):
   def block_until_ready(self) -> Array: ...
   def copy_to_host_async(self) -> None: ...
   def delete(self) -> None: ...
-  def device(self) -> Device: ...
   def devices(self) -> set[Device]: ...
   @property
   def sharding(self) -> Sharding: ...

jax/_src/core.py

@@ -849,11 +849,6 @@ def delete(self):
       f"The delete() method was called on {self._error_repr()}."
       f"{self._origin_msg()}")
 
-  def device(self):
-    raise ConcretizationTypeError(self,
-      f"The device() method was called on {self._error_repr()}."
-      f"{self._origin_msg()}")
-
   def devices(self):
     raise ConcretizationTypeError(self,
       f"The devices() method was called on {self._error_repr()}."

jax/experimental/array_api/_array_methods.py

@@ -19,6 +19,7 @@
 import jax
 from jax._src.array import ArrayImpl
 from jax.experimental.array_api._version import __array_api_version__
+from jax.sharding import Sharding
 
 from jax._src.lib import xla_extension as xe
 
@@ -30,16 +31,15 @@ def _array_namespace(self, /, *, api_version: None | str = None):
   return jax.experimental.array_api
 
 
-def _to_device(self, device: xe.Device | Callable[[], xe.Device], /, *,
+def _to_device(self, device: xe.Device | Sharding | None, *,
                stream: int | Any | None = None):
   if stream is not None:
     raise NotImplementedError("stream argument of array.to_device()")
-  # The type of device is defined by Array.device. In JAX, this is a callable that
-  # returns a device, so we must handle this case to satisfy the API spec.
-  return jax.device_put(self, device() if callable(device) else device)
+  return jax.device_put(self, device)
 
 
 def add_array_object_methods():
   # TODO(jakevdp): set on tracers as well?
   setattr(ArrayImpl, "__array_namespace__", _array_namespace)
   setattr(ArrayImpl, "to_device", _to_device)
+  setattr(ArrayImpl, "device", property(lambda self: self.sharding))

tests/random_test.py

@@ -33,7 +33,6 @@
 from jax import random
 from jax._src import config
 from jax._src import core
-from jax._src import deprecations
 from jax._src import dtypes
 from jax._src import test_util as jtu
 from jax import vmap
@@ -1019,9 +1018,6 @@ def test_array_impl_attributes(self):
 
     self.assertEqual(key.is_fully_addressable, key._base_array.is_fully_addressable)
     self.assertEqual(key.is_fully_replicated, key._base_array.is_fully_replicated)
-    if not deprecations.is_accelerated('jax._src.array', 'device-method'):
-      with jtu.ignore_warning(category=DeprecationWarning, message="arr.device"):
-        self.assertEqual(key.device(), key._base_array.device())
     self.assertEqual(key.devices(), key._base_array.devices())
     self.assertEqual(key.on_device_size_in_bytes(),
                      key._base_array.on_device_size_in_bytes())