Multi-pass reader

paddle/fluid/operators/reader/CMakeLists.txt

@@ -21,5 +21,6 @@ reader_library(create_shuffle_reader_op SRCS create_shuffle_reader_op.cc)
 reader_library(create_batch_reader_op SRCS create_batch_reader_op.cc)
 reader_library(create_recordio_file_reader_op SRCS create_recordio_file_reader_op.cc)
 reader_library(create_double_buffer_reader_op SRCS create_double_buffer_reader_op.cc)
+reader_library(create_multi_pass_reader_op SRCS create_multi_pass_reader_op.cc)
 # Export local libraries to parent
 set(READER_LIBRARY ${LOCAL_READER_LIBS} PARENT_SCOPE)

paddle/fluid/operators/reader/create_multi_pass_reader_op.cc

@@ -0,0 +1,101 @@
+//   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.
+
+#include "paddle/fluid/operators/detail/safe_ref.h"
+#include "paddle/fluid/operators/reader/reader_op_registry.h"
+
+namespace paddle {
+namespace operators {
+namespace reader {
+
+class MultiPassReader : public framework::DecoratedReader {
+ public:
+  MultiPassReader(ReaderBase* reader, int pass_num)
+      : DecoratedReader(reader), pass_num_(pass_num), pass_count_(0) {}
+
+  void ReadNext(std::vector<framework::LoDTensor>* out) override {
+    if (!HasNext()) {
+      PADDLE_THROW("There is no next data!");
+    }
+    reader_->ReadNext(out);
+  }
+
+  bool HasNext() const override {
+    if (reader_->HasNext()) {
+      return true;
+    } else {
+      ++pass_count_;
+      if (pass_count_ >= pass_num_) {
+        return false;
+      } else {
+        reader_->ReInit();
+        return true;
+      }
+    }
+  }
+
+  void ReInit() override {
+    pass_count_ = 0;
+    reader_->ReInit();
+  }
+
+ private:
+  int pass_num_;
+  mutable int pass_count_;
+};
+
+class CreateMultiPassReaderOp : public framework::OperatorBase {
+ public:
+  using framework::OperatorBase::OperatorBase;
+
+ private:
+  void RunImpl(const framework::Scope& scope,
+               const platform::Place& dev_place) const override {
+    const auto& underlying_reader = scope.FindVar(Input("UnderlyingReader"))
+                                        ->Get<framework::ReaderHolder>();
+    auto& out = detail::Ref(scope.FindVar(Output("Out")));
+    int pass_num = Attr<int>("pass_num");
+    out.GetMutable<framework::ReaderHolder>()->Reset(
+        new MultiPassReader(underlying_reader.Get(), pass_num));
+  }
+};
+
+class CreateMultiPassReaderOpMaker : public DecoratedReaderMakerBase {
+ public:
+  CreateMultiPassReaderOpMaker(OpProto* op_proto, OpAttrChecker* op_checker)
+      : DecoratedReaderMakerBase(op_proto, op_checker) {
+    AddAttr<int>("pass_num", "The number of pass to run.").GreaterThan(0);
+    AddComment(R"DOC(
+      CreateMultiPassReader Operator
+
+      This operator creates a multi-pass reader. A multi-pass reader 
+      is used to yield data for several pass training continuously. 
+      It takes the the number of pass to run as one of its attributes
+      ('pass_num'), and maintains a pass counter to record how many 
+      passes it has completed. When the underlying reader reach the EOF, 
+      the multi-pass reader checks whether it has completed training 
+      of the given number of pass. If not, the underlying reader will 
+      be re-initialized and starts a new pass automatically.
+    )DOC");
+  }
+};
+
+}  // namespace reader
+}  // namespace operators
+}  // namespace paddle
+
+namespace ops = paddle::operators::reader;
+REGISTER_DECORATED_READER_OPERATOR(create_multi_pass_reader,
+                                   ops::CreateMultiPassReaderOp,
+                                   ops::CreateMultiPassReaderOpMaker);

python/paddle/fluid/layers/io.py

@@ -22,7 +22,7 @@
 __all__ = [
     'data', 'BlockGuardServ', 'ListenAndServ', 'Send', 'open_recordio_file',
     'open_files', 'read_file', 'create_shuffle_reader',
-    'create_double_buffer_reader'
+    'create_double_buffer_reader', 'create_multi_pass_reader'
 ]
 
 
@@ -345,6 +345,11 @@ def create_double_buffer_reader(reader, place=None):
                                        attrs)
 
 
+def create_multi_pass_reader(reader, pass_num):
+    return __create_decorated_reader__('create_multi_pass_reader', reader,
+                                       {'pass_num': int(pass_num)})
+
+
 def read_file(file_obj):
     helper = LayerHelper('read_file')
     out = [

python/paddle/fluid/tests/unittests/test_multi_pass_reader.py

@@ -0,0 +1,65 @@
+#   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.
+
+import unittest
+
+import paddle.fluid as fluid
+import paddle.v2 as paddle
+import paddle.v2.dataset.mnist as mnist
+
+
+class TestMultipleReader(unittest.TestCase):
+    def setUp(self):
+        self.batch_size = 64
+        self.pass_num = 3
+        # Convert mnist to recordio file
+        with fluid.program_guard(fluid.Program(), fluid.Program()):
+            data_file = paddle.batch(mnist.train(), batch_size=self.batch_size)
+            feeder = fluid.DataFeeder(
+                feed_list=[
+                    fluid.layers.data(
+                        name='image', shape=[784]),
+                    fluid.layers.data(
+                        name='label', shape=[1], dtype='int64'),
+                ],
+                place=fluid.CPUPlace())
+            self.num_batch = fluid.recordio_writer.convert_reader_to_recordio_file(
+                './mnist.recordio', data_file, feeder)
+
+    def test_main(self):
+        with fluid.program_guard(fluid.Program(), fluid.Program()):
+            data_file = fluid.layers.open_recordio_file(
+                filename='./mnist.recordio',
+                shapes=[(-1, 784), (-1, 1)],
+                lod_levels=[0, 0],
+                dtypes=['float32', 'int64'])
+            data_file = fluid.layers.create_multi_pass_reader(
+                reader=data_file, pass_num=self.pass_num)
+            img, label = fluid.layers.read_file(data_file)
+
+            if fluid.core.is_compiled_with_cuda():
+                place = fluid.CUDAPlace(0)
+            else:
+                place = fluid.CPUPlace()
+
+            exe = fluid.Executor(place)
+            exe.run(fluid.default_startup_program())
+
+            batch_count = 0
+            while not data_file.eof():
+                img_val, = exe.run(fetch_list=[img])
+                batch_count += 1
+                self.assertLessEqual(img_val.shape[0], self.batch_size)
+            data_file.reset()
+            self.assertEqual(batch_count, self.num_batch * self.pass_num)