torch / torch.futures
torch.futures¶
Warning
The torch.futures
package is a Prototype feature and subject to change.
This package provides a Future
type that encapsulates
an asynchronous execution and a set of utility functions to simplify operations
on Future
objects. Currently, the
Future
type is primarily used by the
Distributed RPC Framework.
-
class
torch.futures.
Future
¶ Wrapper around a
torch._C.Future
which encapsulates an asynchronous execution of a callable, e.g.rpc_async()
. It also exposes a set of APIs to add callback functions and set results.-
done
() → bool[source]¶ Return
True
if thisFuture
is done. AFuture
is done if it has a result or an exception.
-
set_result
(result: T) → None[source]¶ Set the result for this
Future
, which will mark thisFuture
as completed and trigger all attached callbacks. Note that aFuture
cannot be marked completed twice.- Parameters
result (object) – the result object of this
Future
.
- Example::
>>> import threading >>> import time >>> import torch >>> >>> def slow_set_future(fut, value): >>> time.sleep(0.5) >>> fut.set_result(value) >>> >>> fut = torch.futures.Future() >>> t = threading.Thread( >>> target=slow_set_future, >>> args=(fut, torch.ones(2) * 3) >>> ) >>> t.start() >>> >>> print(fut.wait()) # tensor([3., 3.]) >>> t.join()
-
then
(callback)[source]¶ Append the given callback function to this
Future
, which will be run when theFuture
is completed. Multiple callbacks can be added to the sameFuture
, and will be invoked in the same order as they were added. The callback must take one argument, which is the reference to thisFuture
. The callback function can use theFuture.wait()
API to get the value.- Parameters
callback (
Callable
) – aCallable
that takes thisFuture
as the only argument.- Returns
A new
Future
object that holds the return value of thecallback
and will be marked as completed when the givencallback
finishes.
- Example::
>>> import torch >>> >>> def callback(fut): >>> print(f"RPC return value is {fut.wait()}.") >>> >>> fut = torch.futures.Future() >>> # The inserted callback will print the return value when >>> # receiving the response from "worker1" >>> cb_fut = fut.then(callback) >>> chain_cb_fut = cb_fut.then( >>> lambda x : print(f"Chained cb done. {x.wait()}") >>> ) >>> fut.set_result(5) >>> >>> # Outputs are: >>> # RPC return value is 5. >>> # Chained cb done. None
-
value
(self: torch._C.Future) → object¶
-
-
torch.futures.
collect_all
(futures: List[torch.jit.Future]) → torch.futures.Future[List[torch.jit.Future]][source]¶ Collects the provided
Future
objects into a single combinedFuture
that is completed when all of the sub-futures are completed.- Parameters
- Returns
Returns a
Future
object to a list of the passed in Futures.
- Example::
>>> import torch >>> >>> fut0 = torch.futures.Future() >>> fut1 = torch.futures.Future() >>> >>> fut = torch.futures.collect_all([fut0, fut1]) >>> >>> fut0.set_result(0) >>> fut1.set_result(1) >>> >>> fut_list = fut.wait() >>> print(f"fut0 result = {fut_list[0].wait()}") >>> print(f"fut1 result = {fut_list[1].wait()}") >>> # outputs: >>> # fut0 result = 0 >>> # fut1 result = 1
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