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Paddle/python/paddle/fluid/concurrency.py

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# Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
#
# 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
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from layers.control_flow import BlockGuard, Select
from layer_helper import LayerHelper, unique_name
from layers import fill_constant
import core
__all__ = [
'Go', 'make_channel', 'channel_send', 'channel_recv', 'channel_close',
'Select'
]
class Go(BlockGuard):
def __init__(self, name=None):
self.helper = LayerHelper("go", name=name)
super(Go, self).__init__(self.helper.main_program)
def __enter__(self):
super(Go, self).__enter__()
def __exit__(self, exc_type, exc_val, exc_tb):
if exc_type is not None:
return False
self.construct_go_op()
return super(Go, self).__exit__(exc_type, exc_val, exc_tb)
def construct_go_op(self):
main_program = self.helper.main_program
go_block = main_program.current_block()
parent_block = main_program.block(main_program.current_block()
.parent_idx)
inner_outputs = set()
x_name_list = set()
for op in go_block.ops:
# Iterate over all operators, get all the inputs
# and add as input to the Go operator.
for iname in op.input_names:
for in_var_name in op.input(iname):
if in_var_name not in inner_outputs:
x_name_list.add(in_var_name)
for oname in op.output_names:
for out_var_name in op.output(oname):
inner_outputs.add(out_var_name)
# Iterate over all operators , get all the outputs
# add to the output list of Go operator only if
# they exist in the parent block.
out_vars = []
for inner_out_name in inner_outputs:
if inner_out_name in parent_block.vars:
out_vars.append(parent_block.var(inner_out_name))
parent_block.append_op(
type='go',
inputs={
'X':
[parent_block.var_recursive(x_name) for x_name in x_name_list]
},
outputs={},
attrs={'sub_block': go_block})
def make_channel(dtype, capacity=0):
"""
Helps implementation of a concurrent program by creating a "channel" of
a defined data type. Channels allow for the passing of data in
concurrent scenarios - such as when using threads to divide computation.
Channels can be used to "send" and "receive" such data concurrently.
There are two kinds of channels: unbuffered and buffered. Unbuffered
channels have no capacity - and thus, block on send and only unblock only
once what they have sent has been received.
On the other hand, buffered channels are initialized with a capacity -
and do not block on sends.
Use this method in combination with `channel_send`, `channel_recv`,
`channel_close`, and `Go` to design a concurrent Paddle program.
Args:
dtype (ParamAttr|string): Data type of the data sent in the channel.
This data type should be the string name of a numpy data type.
capacity (ParamAttr|int): Size of the channel. Defaults to 0 for
to create an unbuffered channel.
Returns:
Variable: The channel variable that can be used to send an receive data
of the defined dtype.
Examples:
.. code-block:: python
ch = fluid.make_channel(dtype='int32', capacity=10)
...
# Code to execute in a Go block, which receives the channel data.
fluid.channel_send(ch, 100)
fluid.channel_close(ch)
"""
helper = LayerHelper('channel_create', **locals())
main_program = helper.main_program
make_channel_block = main_program.current_block()
# Make a channel variable (using the channel data type) and make sure it
# persists into the global scope.
channel = helper.create_variable(
name=unique_name.generate('channel'),
type=core.VarDesc.VarType.CHANNEL,
persistable=True)
create_channel_op = make_channel_block.append_op(
type="channel_create",
outputs={"Out": channel},
attrs={"data_type": dtype,
"capacity": capacity})
return channel
def channel_send(channel, value, copy=False):
"""
Sends a value through a channel variable. Used by an unbuffered or buffered
channel to pass data from within or to a concurrent Go block, where
`channel_recv` to used to get the passed value.
Args:
channel (Variable|Channel): Channel variable created using
`make_channel`.
value (Variable): Value to send to channel
copy (bool): Copy data while channel send. If False, then data
is moved. The input cannot be used after move.
Returns:
Variable: The boolean status on whether or not the channel
successfully sent the passed value.
Examples:
.. code-block:: python
ch = fluid.make_channel(dtype='int32', capacity=10)
...
# Code to execute in a Go block, which receives the channel data.
fluid.channel_send(ch, 100)
"""
helper = LayerHelper('channel_send', **locals())
main_program = helper.main_program
channel_send_block = main_program.current_block()
status = helper.create_variable(
name=unique_name.generate('status'),
type=core.VarDesc.VarType.LOD_TENSOR,
dtype=core.VarDesc.VarType.BOOL)
X = value
if copy is True:
copied_X = helper.create_variable(
name=unique_name.generate(value.name + '_copy'),
type=value.type,
dtype=value.dtype,
shape=value.shape,
lod_level=value.lod_level,
capacity=value.capacity)
assign_op = channel_send_block.append_op(
type="assign_op", inputs={"X": value}, outputs={"Out": copied_X})
X = copied_X
channel_send_op = channel_send_block.append_op(
type="channel_send",
inputs={
"Channel": channel,
"X": X,
},
outputs={"Status": status})
return status
def channel_recv(channel, return_value):
"""
Receives a value through a channel variable. Used by an unbuffered or
buffered channel within a concurrent Go block to get data from originally
sent using `channel_send`, or from outside such a block where
`channel_send` is used to send the value.
Args:
channel (Variable|Channel): Channel variable created using
`make_channel`.
return_value (Variable): Variable to set as a result of running channel_recv_op
Returns:
Variable: The received value from the channel.
Variable: The boolean status on whether or not the channel
successfully received the passed value.
Examples:
.. code-block:: python
ch = fluid.make_channel(dtype='int32', capacity=10)
with fluid.Go():
returned_value, return_status = fluid.channel_recv(ch, 'int32')
# Code to send data through the channel.
"""
helper = LayerHelper('channel_recv', **locals())
main_program = helper.main_program
channel_recv_block = main_program.current_block()
status = helper.create_variable(
name=unique_name.generate('status'),
type=core.VarDesc.VarType.LOD_TENSOR,
dtype=core.VarDesc.VarType.BOOL)
channel_recv_op = channel_recv_block.append_op(
type="channel_recv",
inputs={"Channel": channel},
outputs={"Out": return_value,
"Status": status})
return return_value, status
def channel_close(channel):
"""
Closes a channel created using `make_channel`.
Args:
channel (Variable|Channel): Channel variable created using
`make_channel`.
Examples:
.. code-block:: python
ch = fluid.make_channel(dtype='int32', capacity=10)
...
# Code to receive and send data through a channel
...
fluid.channel_close(ch)
"""
helper = LayerHelper('channel_close', **locals())
main_program = helper.main_program
channel_close_block = main_program.current_block()
channel_close_op = channel_close_block.append_op(
type="channel_close", inputs={"Channel": channel})