chainer.function_hooks.PrintHook¶
-
class
chainer.function_hooks.
PrintHook
(sep=None, end='n', file=<_io.TextIOWrapper name='<stdout>' mode='w' encoding='UTF-8'>, flush=True)[source]¶ Function hook that prints debug information.
This function hook outputs the debug information of input arguments of
forward
andbackward
methods involved in the hooked functions at preprocessing time (that is, just before each method is called).Unlike simple “debug print” technique, where users insert print functions at every function to be inspected, we can show the information of all functions involved with single
with
statement.Further, this hook enables us to show the information of
backward
methods without inserting print functions into Chainer’s library code.- Parameters
sep – (deprecated since v4.0.0) Ignored.
end – Character to be added at the end of print function.
file – Output file_like object that that redirect to.
flush – If
True
, this hook forcibly flushes the text stream at the end of preprocessing.
Example
The basic usage is to use it with
with
statement.>>> from chainer import function_hooks >>> l = L.Linear(10, 10) >>> x = chainer.Variable(np.zeros((1, 10), np.float32)) >>> with chainer.function_hooks.PrintHook(): ... y = l(x) ... z = F.sum(y) ... z.backward() # doctest:+SKIP
In this example,
PrintHook
shows the debug information of forward propagation ofLinearFunction
(which is implicitly called byl
) andSum
(called byF.sum
) and backward propagation ofz
andy
.Methods
-
added
(function)[source]¶ Callback function invoked when the function hook is registered
- Parameters
function (FunctionNode) – Function object to which the function hook is added.
None
if the function hook is registered globally.
-
backward_postprocess
(function, in_data, out_grad)[source]¶ Callback function invoked after backward propagation.
- Parameters
function (FunctionNode) – Function object to which the function hook is registered.
in_data (tuple of N-dimensional array) – Input of forward propagation.
out_grad (tuple of N-dimensional array) – Gradient data of backward propagation.
-
backward_preprocess
(function, in_data, out_grad)[source]¶ Callback function invoked before backward propagation.
- Parameters
function (FunctionNode) – Function object to which the function hook is registered.
in_data (tuple of N-dimensional array) – Input data of forward propagation.
out_grad (tuple of N-dimensional array) – Gradient data of backward propagation.
-
deleted
(function)[source]¶ Callback function invoked when the function hook is unregistered
- Parameters
function (FunctionNode) – Function object from which the function hook is deleted.
None
if the function hook was registered globally.
-
forward_postprocess
(function, in_data)[source]¶ Callback function invoked after forward propagation.
- Parameters
function (FunctionNode) – Function object to which the function hook is registered.
in_data (tuple of N-dimensional array) – Input data of forward propagation.
-
forward_preprocess
(function, in_data)[source]¶ Callback function invoked before forward propagation.
- Parameters
function (FunctionNode) – Function object to which the function hook is registered.
in_data (tuple of N-dimensional array) – Input data of forward propagation.
-
__eq__
()¶ Return self==value.
-
__ne__
()¶ Return self!=value.
-
__lt__
()¶ Return self<value.
-
__le__
()¶ Return self<=value.
-
__gt__
()¶ Return self>value.
-
__ge__
()¶ Return self>=value.
Attributes
-
name
= 'PrintHook'¶