fix lod_level share bug in read_op

test=develop

paddle/fluid/operators/read_op.cc

@@ -33,6 +33,19 @@ class ReadInferShape : public framework::InferShapeBase {
         reader_dims.size(), out_names.size(),
         "The reader's dim number doesn't match the output number.");
     ctx->SetOutputsDim("Out", reader_dims);
+    if (!ctx->IsRuntime()) {
+      auto in_desc =
+          boost::get<framework::VarDesc*>(ctx->GetInputVarPtrs("Reader")[0]);
+      auto in_lod_levels = in_desc->GetLoDLevels();
+      auto out_var_ptrs = ctx->GetOutputVarPtrs("Out");
+      PADDLE_ENFORCE_EQ(in_lod_levels.size(), out_var_ptrs.size(),
+                        "LoDLevels of Input(Reader) must be the same as the "
+                        "number of Outputs(Out).");
+      for (size_t i = 0; i < out_var_ptrs.size(); ++i) {
+        auto* out_desc = boost::get<framework::VarDesc*>(out_var_ptrs[i]);
+        out_desc->SetLoDLevel(in_lod_levels[i]);
+      }
+    }
   }
 };
 

python/paddle/fluid/layers/io.py

@@ -315,6 +315,7 @@ def _copy_reader_var_(block, var):
     new_var = block.create_var(name=var.name, type=core.VarDesc.VarType.READER)
     new_var.desc.set_shapes(var.desc.shapes())
     new_var.desc.set_dtypes(var.desc.dtypes())
+    new_var.desc.set_lod_levels(var.desc.lod_levels())
     new_var.persistable = True
     return new_var
 

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

+# 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 paddle.fluid as fluid
+import unittest
+
+
+class TestLoDLevelShare(unittest.TestCase):
+    def setUp(self):
+        self.use_double_buffer = False
+
+    def test_lod_level_share(self):
+        reader = fluid.layers.py_reader(
+            capacity=16,
+            shapes=([-1, 256], [-1, 512], [-1, 100]),
+            dtypes=('float32', 'int64', 'double'),
+            lod_levels=(1, 2, 0),
+            use_double_buffer=self.use_double_buffer)
+
+        x, y, z = fluid.layers.read_file(reader)
+        self.assertEqual(x.lod_level, 1)
+        self.assertEqual(y.lod_level, 2)
+        self.assertEqual(z.lod_level, 0)
+
+
+class TestLoDLevelShare2(TestLoDLevelShare):
+    def setUp(self):
+        self.use_double_buffer = True
+
+
+if __name__ == '__main__':
+    unittest.main()