torch / torch
no_grad¶
-
class
torch.
no_grad
[source]¶ Context-manager that disabled gradient calculation.
Disabling gradient calculation is useful for inference, when you are sure that you will not call
Tensor.backward()
. It will reduce memory consumption for computations that would otherwise have requires_grad=True.In this mode, the result of every computation will have requires_grad=False, even when the inputs have requires_grad=True.
This context manager is thread local; it will not affect computation in other threads.
Also functions as a decorator. (Make sure to instantiate with parenthesis.)
Example:
>>> x = torch.tensor([1], requires_grad=True) >>> with torch.no_grad(): ... y = x * 2 >>> y.requires_grad False >>> @torch.no_grad() ... def doubler(x): ... return x * 2 >>> z = doubler(x) >>> z.requires_grad False
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