You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
Paddle/python/paddle/fluid/reader.py

142 lines
4.3 KiB

# Copyright (c) 2019 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.
import core
import six
import threading
from .framework import Program, Variable, program_guard
from .data_feeder import DataFeeder
__all__ = ['PyReader']
def _convert_places(places):
if not isinstance(places, (list, tuple)):
places = [places]
ret = []
for p in places:
if not isinstance(p, core.Place):
tmp = core.Place()
tmp.set_place(p)
p = tmp
ret.append(p)
return ret
class PyReader(object):
def __init__(self, feed_list, places, capacity, multi_queue=True):
self._tensor_reader = None
self._thread = None
# TODO(zjl): to support drop_last = False
self._drop_last = True
self._feed_list = feed_list
self._var_names = [v.name for v in feed_list]
self._queues = []
self._places = _convert_places(places)
self._queue_capacity = capacity
queue_num = len(self._places) if multi_queue else 1
for _ in six.moves.range(queue_num):
self._queues.append(
core.init_lod_tensor_blocking_queue(core.Variable(),
self._queue_capacity))
self._reader = core.create_py_reader(self._queues, self._var_names,
self._places, self._drop_last)
self._exited = True
def __call__(self):
assert self._tensor_reader is not None, \
"Data source of PyReader has not set yet"
class Iterator(object):
def __init__(self, reader):
self._reader = reader
def __iter__(self):
return self
def next(self):
ret = self._reader._reader.read_next()
if len(ret):
return ret
else:
self._reader._restart_reader()
self._reader._reader.reset()
raise StopIteration
return Iterator(self)
def _restart_reader(self):
if not self._exited:
for q in self._queues:
q.close()
self._thread.join()
def __thread_main__():
queue_num = len(self._queues)
idx = 0
for tensors in self._tensor_reader():
array = core.LoDTensorArray()
for item in tensors:
if not isinstance(item, core.LoDTensor):
tmp = core.LoDTensor()
tmp.set(item, core.CPUPlace())
item = tmp
array.append(item)
if not self._queues[idx].push(array):
break
idx = (idx + 1) % queue_num
for q in self._queues:
q.close()
self._exited = True
self._thread = threading.Thread(target=__thread_main__)
self._thread.daemon = True
self._exited = False
self._thread.start()
def set_numpy_reader(self, reader):
assert self._tensor_reader is None, \
"Cannot reset the data source of PyReader"
with program_guard(Program(), Program()):
feeder = DataFeeder(
feed_list=self._feed_list, place=core.CPUPlace())
paddle_reader = feeder.decorate_reader(reader, multi_devices=False)
def __tensor_reader_impl__():
for slots in paddle_reader():
yield [slots[var.name] for var in self._feed_list]
self.set_tensor_reader(__tensor_reader_impl__)
def set_tensor_reader(self, reader):
assert self._tensor_reader is None, \
"Cannot reset the data source of PyReader"
self._tensor_reader = reader
self._restart_reader()