Make make_array_from_process_local_data go via device_put if ther…

…e is only 1 process.

PiperOrigin-RevId: 677232996

jax/_src/array.py

@@ -892,17 +892,20 @@ def make_array_from_process_local_data(
   setting it to (4, 4) in this case.
 
   Args:
-    sharding: sharding of the global tensor.
-    local_data: data on the host to be placed on local devices. Each
+    sharding: Sharding of the global array.
+    local_data: Data on the host to be placed on local devices. Each
       dimension should either match global_shape, or match
       num_addressable_indices(dim).
-    global_shape: the target shape of the global tensor. If None,
+    global_shape: The target shape of the global array. If None,
       will infer from local_data and sharding.
 
   Returns:
     Tensor that will have sharding=sharding and of shape global_shape.
   """
   # pyformat: enable
+  if xla_bridge.process_count() == 1:
+    return api.device_put(local_data, sharding)
+
   # TODO(sandler): consider supporting partially specified global_shape or
   # making local_to_global_shape available in the api.
   local_shape = local_data.shape

tests/array_test.py

@@ -822,18 +822,12 @@ def test_make_array_from_callback_global_array(self):
     self.assertEqual(out2.sharding, sharding2)
 
   def test_make_array_from_process_data_single_host_data_sharding(self):
-    data = np.ones((1, 512))
-    mesh = jtu.create_mesh((1, 1), ('x', 'unused'))
-    sharding_spec = jax.sharding.NamedSharding(
-        mesh, jax.sharding.PartitionSpec('x')
-    )
-    global_shape = data.shape
-    result = jax.make_array_from_process_local_data(
-        sharding_spec, data, global_shape
-    )
-    self.assertIsInstance(result, jax.Array)
-    self.assertEqual(result.shape, data.shape)
-    self.assertEqual(result.sharding, sharding_spec)
+    mesh = jtu.create_mesh((2, 1), ('x', 'y'))
+    data = np.ones((256, 512))
+    s = jax.NamedSharding(mesh, P('x'))
+    result = jax.make_array_from_process_local_data(s, data)
+    self.assertArraysEqual(result, data)
+    self.assertEqual(result.sharding, s)
 
 class ShardingTest(jtu.JaxTestCase):