# Copyright 2017,2018,2019,2020,2021 Sony Corporation.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
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"""
NNabla Context manager
"""
from __future__ import absolute_import
from contextlib import contextmanager
from .variable import Context
current_ctx = Context()
context_level = 0
[docs]@contextmanager
def context_scope(ctx):
"""
Context as Python context.
.. code-block:: python
import nnabla as nn
import nnabla.functions as F
x = nn.Variable([2, 3 ,4])
ctx = nnabla_ext.cuda.context('0')
with context_scope(ctx):
# Inside with scope, the specified context is used.
with parameter_scope('w1'):
l1 = F.relu(F.affine(x, 64))
with parameter_scope('w2'):
l2 = F.relu(F.affine(x, 64))
"""
global current_ctx
global context_level
context_level += 1
prev_context = current_ctx
current_ctx = ctx
try:
yield
finally:
context_level -= 1
current_ctx = prev_context
[docs]def set_default_context(ctx):
"""
Set the default context.
Note:
It cannot be called inside any `context_scope`.
Args:
ctx (Context): A Context.
"""
global context_level
global current_ctx
assert context_level == 0, "It cannot be called inside any context_scope."
current_ctx = ctx
[docs]def get_current_context():
"""
Get the current context.
It can be set using :meth:`nnabla.context_scope` or :meth:`nnabla.set_default_context` .
Returns:
Context: a current context.
"""
global current_ctx
return current_ctx