tf.DeviceSpec
tf.DeviceSpec
class tf.DeviceSpec
Defined in tensorflow/python/framework/device.py
.
Represents a (possibly partial) specification for a TensorFlow device.
DeviceSpec
s are used throughout TensorFlow to describe where state is stored and computations occur. Using DeviceSpec
allows you to parse device spec strings to verify their validity, merge them or compose them programmatically.
Example:
# Place the operations on device "GPU:0" in the "ps" job. device_spec = DeviceSpec(job="ps", device_type="GPU", device_index=0) with tf.device(device_spec): # Both my_var and squared_var will be placed on /job:ps/device:GPU:0. my_var = tf.Variable(..., name="my_variable") squared_var = tf.square(my_var)
If a DeviceSpec
is partially specified, it will be merged with other DeviceSpec
s according to the scope in which it is defined. DeviceSpec
components defined in inner scopes take precedence over those defined in outer scopes.
with tf.device(DeviceSpec(job="train", )): with tf.device(DeviceSpec(job="ps", device_type="GPU", device_index=0): # Nodes created here will be assigned to /job:ps/device:GPU:0. with tf.device(DeviceSpec(device_type="GPU", device_index=1): # Nodes created here will be assigned to /job:train/device:GPU:1.
A DeviceSpec
consists of 5 components -- each of which is optionally specified:
- Job: The job name.
- Replica: The replica index.
- Task: The task index.
- Device type: The device type string (e.g. "CPU" or "GPU").
- Device index: The device index.
Properties
job
replica
task
Methods
__init__
__init__( job=None, replica=None, task=None, device_type=None, device_index=None )
Create a new DeviceSpec
object.
Args:
-
job
: string. Optional job name. -
replica
: int. Optional replica index. -
task
: int. Optional task index. -
device_type
: Optional device type string (e.g. "CPU" or "GPU") -
device_index
: int. Optional device index. If left unspecified, device represents 'any' device_index.
from_string
from_string(spec)
Construct a DeviceSpec
from a string.
Args:
-
spec
: a string of the form /job:/replica: /task: /device:CPU: or /job: /replica: /task: /device:GPU: as cpu and gpu are mutually exclusive. All entries are optional.
Returns:
A DeviceSpec.
merge_from
merge_from(dev)
Merge the properties of "dev" into this DeviceSpec
.
Args:
-
dev
: aDeviceSpec
.
parse_from_string
parse_from_string(spec)
Parse a DeviceSpec
name into its components.
Args:
-
spec
: a string of the form /job:/replica: /task: /device:CPU: or /job: /replica: /task: /device:GPU: as cpu and gpu are mutually exclusive. All entries are optional.
Returns:
The DeviceSpec
.
Raises:
-
ValueError
: if the spec was not valid.
to_string
to_string()
Return a string representation of this DeviceSpec
.
Returns:
a string of the form /job:
© 2017 The TensorFlow Authors. All rights reserved.
Licensed under the Creative Commons Attribution License 3.0.
Code samples licensed under the Apache 2.0 License.
https://www.tensorflow.org/api_docs/python/tf/DeviceSpec