Merge branch 'develop' of https://github.com/paddlepaddle/paddle into add_benchmark_for_trt

test=develop

paddle/fluid/API.spec

@@ -66,6 +66,7 @@ paddle.fluid.layers.linear_chain_crf ArgSpec(args=['input', 'label', 'param_attr
 paddle.fluid.layers.crf_decoding ArgSpec(args=['input', 'param_attr', 'label'], varargs=None, keywords=None, defaults=(None,))
 paddle.fluid.layers.cos_sim ArgSpec(args=['X', 'Y'], varargs=None, keywords=None, defaults=None)
 paddle.fluid.layers.cross_entropy ArgSpec(args=['input', 'label', 'soft_label', 'ignore_index'], varargs=None, keywords=None, defaults=(False, -100))
+paddle.fluid.layers.bpr_loss ArgSpec(args=['input', 'label', 'name'], varargs=None, keywords=None, defaults=(None,))
 paddle.fluid.layers.square_error_cost ArgSpec(args=['input', 'label'], varargs=None, keywords=None, defaults=None)
 paddle.fluid.layers.chunk_eval ArgSpec(args=['input', 'label', 'chunk_scheme', 'num_chunk_types', 'excluded_chunk_types'], varargs=None, keywords=None, defaults=(None,))
 paddle.fluid.layers.sequence_conv ArgSpec(args=['input', 'num_filters', 'filter_size', 'filter_stride', 'padding', 'bias_attr', 'param_attr', 'act', 'name'], varargs=None, keywords=None, defaults=(3, 1, None, None, None, None, None))

paddle/fluid/CMakeLists.txt

 add_subdirectory(memory)
 add_subdirectory(platform)
 add_subdirectory(framework)
+add_subdirectory(imperative)
 add_subdirectory(operators)
 add_subdirectory(string)
 add_subdirectory(recordio)

paddle/fluid/framework/feed_fetch_method.cc

@@ -16,7 +16,9 @@ limitations under the License. */
 #include <string>
 #include <vector>
 #include "glog/logging.h"
+#include "paddle/fluid/framework/var_type.h"
 #include "paddle/fluid/framework/variable.h"
+#include "paddle/fluid/platform/place.h"
 
 namespace paddle {
 namespace framework {
@@ -53,5 +55,12 @@ LoDTensor& GetFetchVariable(const Scope& scope, const std::string& var_name,
   return tensor;
 }
 
+LoDTensor& GetVariableTensor(const Scope& scope, const std::string& var_name) {
+  Variable* var = scope.FindVar(var_name);
+  PADDLE_ENFORCE(var, "%s no in scope", var_name);
+  PADDLE_ENFORCE(var->IsType<LoDTensor>(), "Only support lod tensor now.");
+  return *var->GetMutable<LoDTensor>();
+}
+
 }  // namespace framework
 }  // namespace paddle

paddle/fluid/framework/feed_fetch_method.h

@@ -27,5 +27,7 @@ void SetFeedVariable(Scope* scope, const LoDTensor& input,
 LoDTensor& GetFetchVariable(const Scope& scope, const std::string& var_name,
                             size_t index);
 
+LoDTensor& GetVariableTensor(const Scope& scope, const std::string& var_name);
+
 }  // namespace framework
 }  // namespace paddle

paddle/fluid/framework/ir/graph.cc

@@ -38,9 +38,8 @@ void CheckProgram(const ProgramDesc &program) {
     switch (role_id) {
       case _INT(OpRole::kForward):
         if (visit.find(_INT(OpRole::kBackward)) != visit.end()) {
-          LOG(ERROR)
-              << "Cannot add backward operator before forward operator %s."
-              << op->Type();
+          LOG(ERROR) << "Cannot add backward operator before forward operator "
+                     << op->Type();
         }
         break;
       case _INT(OpRole::kBackward):

paddle/fluid/framework/ir/is_test_pass.cc

@@ -38,7 +38,7 @@ std::unique_ptr<ir::Graph> IsTestPass::ApplyImpl(
   for (const Node* n : graph->Nodes()) {
     if (n->IsOp()) {
       auto* op = n->Op();
-      if (n->RuntimeHasAttr("is_test")) {
+      if (op->HasAttr("is_test") || op->HasProtoAttr("is_test")) {
         op->SetAttr("is_test", true);
       } else if (std::find(begin(op_list), end(op_list), op->Type()) !=
                  end(op_list)) {

paddle/fluid/framework/ir/is_test_pass_tester.cc

@@ -104,9 +104,9 @@ TEST(IsTestPass, basic) {
       auto* op = node->Op();
       auto op_name = boost::get<std::string>(op->GetAttr("name"));
       if (op_name == "conv3") {
-        ASSERT_FALSE(node->RuntimeHasAttr("is_test"));
+        ASSERT_FALSE(op->HasAttr("is_test"));
       } else {
-        ASSERT_TRUE(node->RuntimeHasAttr("is_test"));
+        ASSERT_TRUE(op->HasAttr("is_test"));
         EXPECT_TRUE(boost::get<bool>(op->GetAttr("is_test")));
       }
     }

paddle/fluid/framework/ir/mkldnn_placement_pass.cc

@@ -25,12 +25,15 @@ std::unique_ptr<ir::Graph> MKLDNNPlacementPass::ApplyImpl(
   const auto& op_types_list =
       Get<std::unordered_set<std::string>>("mkldnn_enabled_op_types");
   for (const Node* n : graph->Nodes()) {
-    if (n->IsOp() && n->RuntimeHasAttr("use_mkldnn")) {
-      if (op_types_list.empty()) {
-        n->Op()->SetAttr("use_mkldnn", true);
-      } else if (std::find(op_types_list.begin(), op_types_list.end(),
-                           n->Name()) != op_types_list.end()) {
-        n->Op()->SetAttr("use_mkldnn", true);
+    if (n->IsOp()) {
+      auto* op = n->Op();
+      if (op->HasAttr("use_mkldnn") || op->HasProtoAttr("use_mkldnn")) {
+        if (op_types_list.empty()) {
+          op->SetAttr("use_mkldnn", true);
+        } else if (std::find(op_types_list.begin(), op_types_list.end(),
+                             n->Name()) != op_types_list.end()) {
+          op->SetAttr("use_mkldnn", true);
+        }
       }
     }
   }

paddle/fluid/framework/ir/node.cc

@@ -30,28 +30,6 @@ std::unique_ptr<Node> CreateNodeForTest(const std::string &name,
   return std::unique_ptr<Node>(new Node(name, type));
 }
 
-bool Node::RuntimeHasAttr(const std::string &name) const {
-  if (Op()->HasAttr(name)) {
-    return true;
-  } else {
-    auto &op_info = OpInfoMap::Instance();
-    auto op_type = Op()->Type();
-    if (op_info.Has(op_type)) {
-      auto op_info_ptr = op_info.Get(op_type);
-      if (op_info_ptr.HasOpProtoAndChecker()) {
-        const proto::OpProto &proto = op_info_ptr.Proto();
-        for (int i = 0; i != proto.attrs_size(); ++i) {
-          const proto::OpProto::Attr &attr = proto.attrs(i);
-          if (attr.name() == name) {
-            return true;
-          }
-        }
-      }
-    }
-  }
-  return false;
-}
-
 }  // namespace ir
 }  // namespace framework
 }  // namespace paddle

paddle/fluid/framework/ir/node.h

@@ -108,18 +108,6 @@ class Node {
            Name().find(ir::Node::kControlDepVarName) != std::string::npos;
   }
 
-  // RuntimeHasAttr is different with HasAttr now.
-  // 1. For Op()->HasAttr(), it judges whether a stored program_desc_ has attr,
-  // thus, if stored program_desc_ are old which don't have an attr, a new
-  // library which adds the attr already will fail on this function.
-  // Details:
-  // https://github.com/PaddlePaddle/Paddle/pull/14608#issuecomment-442309087
-  // 2. For Op()->RuntimeHasAttr, it judges the attr in runtime to avoid above
-  // problem.
-  // TODO(luotao): Maybe we should enhance HasAttr later, instead of adding
-  // RuntimeHasAttr.
-  bool RuntimeHasAttr(const std::string& name) const;
-
   std::vector<Node*> inputs;
   std::vector<Node*> outputs;
 

paddle/fluid/framework/op_desc.cc

@@ -237,6 +237,23 @@ void OpDesc::SetOutput(const std::string &param_name,
   this->outputs_[param_name] = args;
 }
 
+bool OpDesc::HasProtoAttr(const std::string &name) const {
+  auto &op_info = OpInfoMap::Instance();
+  if (op_info.Has(desc_.type())) {
+    auto op_info_ptr = op_info.Get(desc_.type());
+    if (op_info_ptr.HasOpProtoAndChecker()) {
+      const proto::OpProto &proto = op_info_ptr.Proto();
+      for (int i = 0; i != proto.attrs_size(); ++i) {
+        const proto::OpProto::Attr &attr = proto.attrs(i);
+        if (attr.name() == name) {
+          return true;
+        }
+      }
+    }
+  }
+  return false;
+}
+
 proto::AttrType OpDesc::GetAttrType(const std::string &name) const {
   auto it = attrs_.find(name);
   PADDLE_ENFORCE(it != attrs_.end(), "Attribute %s is not found", name);

paddle/fluid/framework/op_desc.h

@@ -65,6 +65,8 @@ class OpDesc {
     return attrs_.find(name) != attrs_.end();
   }
 
+  bool HasProtoAttr(const std::string &name) const;
+
   proto::AttrType GetAttrType(const std::string &name) const;
 
   std::vector<std::string> AttrNames() const;

paddle/fluid/imperative/CMakeLists.txt

+cc_library(layer SRCS layer.cc DEPS proto_desc operator)
+cc_library(tracer SRCS tracer.cc DEPS proto_desc)
+cc_library(engine SRCS engine.cc)

paddle/fluid/imperative/engine.cc

+// 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/imperative/engine.h"
+
+#include <mutex>  // NOLINT
+#include <vector>
+
+#include "glog/logging.h"
+
+namespace paddle {
+namespace imperative {
+
+static std::once_flag init_engine;
+static Engine* engine;
+
+class DummyEngine : public Engine {
+ public:
+  void Enqueue(Runnable* runnable) override {
+    queued_runnables_.push_back(runnable);
+  }
+
+  size_t Size() const override { return queued_runnables_.size(); }
+
+  void Sync() override {
+    for (Runnable* l : queued_runnables_) {
+      LOG(INFO) << "running " << reinterpret_cast<void*>(l);
+    }
+    queued_runnables_.clear();
+  }
+
+ private:
+  std::vector<Runnable*> queued_runnables_;
+};
+
+Engine* GetEngine() {
+  std::call_once(init_engine, []() { engine = new DummyEngine(); });
+  return engine;
+}
+
+}  // namespace imperative
+}  // namespace paddle

paddle/fluid/imperative/engine.h

+// 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.
+
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+
+namespace paddle {
+namespace imperative {
+
+struct Runnable {};
+
+class Engine {
+ public:
+  virtual ~Engine() {}
+
+  virtual void Enqueue(Runnable* runnable) = 0;
+
+  virtual size_t Size() const = 0;
+
+  virtual void Sync() = 0;
+};
+
+Engine* GetEngine();
+
+}  // namespace imperative
+}  // namespace paddle

paddle/fluid/imperative/layer.cc

+// 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/imperative/layer.h"
+#include <deque>
+#include <limits>
+#include <map>
+#include <random>
+#include <utility>
+
+#include "paddle/fluid/framework/lod_tensor.h"
+#include "paddle/fluid/framework/op_registry.h"
+#include "paddle/fluid/string/printf.h"
+
+namespace paddle {
+namespace imperative {
+
+using framework::Variable;
+
+void AddTo(Variable* src, Variable* dst) {
+  framework::LoDTensor* dst_tensor = dst->GetMutable<framework::LoDTensor>();
+  framework::LoDTensor* src_tensor = src->GetMutable<framework::LoDTensor>();
+  PADDLE_ENFORCE(dst_tensor->numel() == src_tensor->numel(), "%lld vs %lld",
+                 dst_tensor->numel(), src_tensor->numel());
+  float* dst_data = dst_tensor->mutable_data<float>(platform::CPUPlace());
+  const float* src_data = src_tensor->data<float>();
+  for (size_t i = 0; i < src_tensor->numel(); ++i) {
+    dst_data[i] += src_data[i];
+  }
+}
+
+class Autograd {
+ public:
+  explicit Autograd(framework::Scope* scope) : scope_(scope) {}
+
+  void RunBackward(VarBase* var) {
+    PADDLE_ENFORCE(var->pre_op_->op_desc_);
+    // TODO(panyx0718): Only create for vars that "require_grad"
+    (*var->pre_op_->output_vars_)[var->pre_op_out_idx_]->grads_ = var->grads_;
+
+    std::deque<OpBase*> ready;
+    ready.push_back(var->pre_op_);
+
+    std::map<OpBase*, int> dep_counts = ComputeDepCounts(var->pre_op_);
+
+    while (!ready.empty()) {
+      OpBase* ready_op = ready.front();
+      ready.pop_front();
+      std::vector<Variable*> input_grads = ready_op->ApplyGrad(scope_);
+
+      for (size_t i = 0; i < input_grads.size(); ++i) {
+        if (!input_grads[i]) continue;
+        OpBase* pre_op = ready_op->pre_ops_->at(i);
+        if (!pre_op) continue;
+
+        dep_counts[pre_op] -= 1;
+        PADDLE_ENFORCE(dep_counts[pre_op] >= 0);
+        bool pre_op_ready = dep_counts[pre_op] == 0;
+        if (pre_op_ready) {
+          ready.push_back(pre_op);
+        }
+      }
+    }
+  }
+
+ private:
+  std::map<OpBase*, int> ComputeDepCounts(OpBase* op) {
+    std::map<OpBase*, int> ret;
+
+    std::deque<OpBase*> queue;
+    queue.push_back(op);
+    std::unordered_set<OpBase*> visited;
+    visited.insert(op);
+    while (!queue.empty()) {
+      OpBase* candidate = queue.front();
+      queue.pop_front();
+      for (OpBase* pre_op : *(candidate->pre_ops_)) {
+        if (!pre_op) continue;
+        if (visited.find(pre_op) == visited.end()) {
+          visited.insert(pre_op);
+          queue.push_back(pre_op);
+        }
+        ret[pre_op] += 1;
+      }
+    }
+
+    return ret;
+  }
+
+  framework::Scope* scope_;
+};
+
+framework::Variable* CreateVariable(const std::string& name,
+                                    const framework::DDim& dim, float val,
+                                    framework::Scope* scope,
+                                    bool random_name = true) {
+  std::string varname = name;
+  if (random_name) {
+    std::mt19937 rng;
+    rng.seed(std::random_device()());
+    std::uniform_int_distribution<std::mt19937::result_type> dist6(
+        1, std::numeric_limits<int>::max());
+    int id = dist6(rng);
+    varname = string::Sprintf("%s@%d", varname, id);
+  }
+
+  VLOG(3) << "creating var " << varname;
+  framework::Variable* var = scope->Var(varname);
+  framework::LoDTensor* tensor = var->GetMutable<framework::LoDTensor>();
+
+  float* data = tensor->mutable_data<float>(dim, platform::CPUPlace());
+  std::fill(data, data + tensor->numel(), val);
+  return var;
+}
+
+framework::LoDTensor& VarBase::Grad() {
+  VLOG(3) << "get var grad " << var_desc_->Name();
+  return *grads_->GetMutable<framework::LoDTensor>();
+}
+
+void VarBase::ApplyGrad(framework::Scope* scope, Variable* grad) {
+  VLOG(3) << "apply var grad " << var_desc_->Name() << " "
+          << grad->Get<framework::LoDTensor>().data<float>()[0];
+  if (!grads_) {
+    grads_ =
+        CreateVariable(string::Sprintf("%s@IGrad", var_desc_->Name()),
+                       var_->Get<framework::LoDTensor>().dims(), 0.0, scope);
+  }
+  AddTo(grad, grads_);
+  VLOG(3) << "grad_ after apply var grad " << var_desc_->Name() << " "
+          << grads_->Get<framework::LoDTensor>().data<float>()[0];
+}
+
+std::vector<Variable*> OpBase::ApplyGrad(framework::Scope* scope) {
+  VLOG(3) << "op grad " << grad_op_desc_->Type();
+
+  for (const std::string& grad_invar : grad_op_desc_->InputArgumentNames()) {
+    if (grad_to_var_->find(grad_invar) == grad_to_var_->end()) {
+      // grad op inputs can be forward inputs, so not in grad_to_var.
+      continue;
+    }
+    VLOG(3) << "op grad in var " << grad_invar;
+    block_->FindRecursiveOrCreateVar(grad_invar);
+    framework::Variable* var = scope->Var(grad_invar);
+    const std::string& invar = grad_to_var_->at(grad_invar);
+    for (VarBase* varbase : *output_vars_) {
+      // Use the accumulated grads_ by sharing the input with grads_.
+      if (varbase->var_desc_->Name() == invar) {
+        var->GetMutable<framework::LoDTensor>()->ShareDataWith(
+            varbase->grads_->Get<framework::LoDTensor>());
+        break;
+      }
+    }
+  }
+
+  for (const std::string& outvar : grad_op_desc_->OutputArgumentNames()) {
+    VLOG(3) << "grad outvar " << outvar;
+    block_->FindRecursiveOrCreateVar(outvar);
+    framework::Variable* var = scope->Var(outvar);
+    if (!var->IsInitialized()) {
+      framework::VarDesc* var_desc = block_->FindVar(outvar);
+      if (var_desc->GetType() == framework::proto::VarType::LOD_TENSOR) {
+        var->GetMutable<framework::LoDTensor>();
+      } else {
+        LOG(ERROR) << "tracer doesn't support yet";
+      }
+    }
+  }
+  grad_op_desc_->InferShape(*block_);
+  grad_op_desc_->InferVarType(block_);
+  std::unique_ptr<framework::OperatorBase> opbase =
+      framework::OpRegistry::CreateOp(*grad_op_desc_);
+
+  opbase->Run(*scope, platform::CPUPlace());
+
+  // `ret` matches exactly with `input_vars_` of forward op.
+  std::vector<Variable*> ret;
+  for (size_t i = 0; i < input_vars_->size(); ++i) {
+    bool found = false;
+    for (const std::string& outvar : grad_op_desc_->OutputArgumentNames()) {
+      Variable* var = scope->FindVar(outvar);
+      VarBase* origin_var = (*input_vars_)[i];
+      std::string orig_var = grad_to_var_->at(outvar);
+      PADDLE_ENFORCE(origin_var->var_desc_->Name() == orig_var);
+      VLOG(3) << "apply grad " << outvar << " with origin " << orig_var;
+      origin_var->ApplyGrad(scope, var);
+      found = true;
+      ret.push_back(var);
+      // TODO(panyx0718): There might be another outvar with the same name.
+      // In that case, it doesn't matter the first one or the second one is
+      // used.
+      break;
+    }
+    if (!found) {
+      ret.push_back(nullptr);
+    }
+  }
+  return ret;
+}
+
+void VarBase::RunBackward(framework::Scope* scope) {
+  grads_ = CreateVariable(framework::GradVarName(var_desc_->Name()),
+                          var_->Get<framework::LoDTensor>().dims(), 1.0, scope,
+                          false);
+  if (!pre_op_) return;
+  Autograd(scope).RunBackward(this);
+}
+
+}  // namespace imperative
+}  // namespace paddle

paddle/fluid/imperative/layer.h

+// 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.
+
+#pragma once
+
+#include <string>
+#include <vector>
+#include "paddle/fluid/framework/op_desc.h"
+#include "paddle/fluid/framework/operator.h"
+#include "paddle/fluid/framework/scope.h"
+#include "paddle/fluid/framework/var_desc.h"
+#include "paddle/fluid/platform/enforce.h"
+
+namespace paddle {
+namespace imperative {
+
+class OpBase;
+
+class VarBase {
+ public:
+  VarBase()
+      : pre_op_(nullptr),
+        pre_op_out_idx_(-1),
+        var_desc_(nullptr),
+        var_(nullptr),
+        grads_(nullptr) {}
+
+  virtual ~VarBase() {}
+
+  void ApplyGrad(framework::Scope* scope, framework::Variable* grad);
+
+  void RunBackward(framework::Scope* scope);
+
+  framework::LoDTensor& Grad();
+
+  OpBase* pre_op_;
+  int pre_op_out_idx_;
+
+  framework::VarDesc* var_desc_;
+  framework::Variable* var_;
+  framework::Variable* grads_;
+};
+
+class OpBase {
+ public:
+  OpBase()
+      : input_vars_(new std::vector<VarBase*>()),
+        output_vars_(new std::vector<VarBase*>()),
+        pre_ops_(new std::vector<OpBase*>()),
+        pre_ops_out_idx_(new std::vector<int>()),
+        op_desc_(nullptr),
+        grad_op_desc_(nullptr) {}
+
+  virtual ~OpBase() {
+    delete input_vars_;
+    delete output_vars_;
+
+    delete pre_ops_;
+    delete pre_ops_out_idx_;
+
+    if (grad_op_desc_) delete grad_op_desc_;
+    if (grad_to_var_) delete grad_to_var_;
+  }
+
+  std::vector<framework::Variable*> ApplyGrad(framework::Scope* scope);
+
+  std::vector<VarBase*>* input_vars_;
+  std::vector<VarBase*>* output_vars_;
+  std::vector<OpBase*>* pre_ops_;
+  std::vector<int>* pre_ops_out_idx_;
+  framework::OpDesc* op_desc_;
+
+  framework::OpDesc* grad_op_desc_;
+  std::unordered_map<std::string, std::string>* grad_to_var_;
+  framework::BlockDesc* block_;
+};
+
+class Layer {
+ public:
+  virtual ~Layer() {}
+
+  virtual std::vector<VarBase> Forward(const std::vector<VarBase>& inputs) {
+    std::vector<VarBase> vars;
+    return vars;
+  }
+
+  virtual void Backward() { LOG(ERROR) << "To support customize"; }
+};
+
+}  // namespace imperative
+}  // namespace paddle

paddle/fluid/imperative/tracer.cc

+// 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/imperative/tracer.h"
+
+namespace paddle {
+namespace imperative {}  // namespace imperative
+}  // namespace paddle

paddle/fluid/imperative/tracer.h

+// 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.
+
+#pragma once
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "paddle/fluid/framework/op_desc.h"
+#include "paddle/fluid/framework/op_registry.h"
+#include "paddle/fluid/framework/scope.h"
+#include "paddle/fluid/imperative/engine.h"
+#include "paddle/fluid/imperative/layer.h"
+
+namespace paddle {
+namespace imperative {
+
+void CreateGradOp(const framework::OpDesc& op_desc,
+                  const std::unordered_set<std::string>& no_grad_set,
+                  const std::vector<framework::BlockDesc*>& grad_sub_block,
+                  framework::OpDesc** grad_op_desc,
+                  std::unordered_map<std::string, std::string>* grad_to_var) {
+  std::vector<std::unique_ptr<framework::OpDesc>> grad_op_descs =
+      framework::OpInfoMap::Instance()
+          .Get(op_desc.Type())
+          .GradOpMaker()(op_desc, no_grad_set, grad_to_var, grad_sub_block);
+  PADDLE_ENFORCE(grad_op_descs.size() == 1, "Only support 1 grad op now.");
+  // TODO(panyx0718): Leak?
+  *grad_op_desc = grad_op_descs[0].release();
+}
+
+class Tracer {
+ public:
+  explicit Tracer(framework::BlockDesc* root_block) : root_block_(root_block) {
+    root_scope_ = new framework::Scope();
+    scopes_[root_block_] = root_scope_;
+  }
+
+  virtual ~Tracer() { delete root_scope_; }
+
+  void Trace(OpBase* op, const std::vector<VarBase*>& inputs,
+             const std::vector<VarBase*>& outputs,
+             framework::BlockDesc* block) {
+    framework::Scope* scope = GetScope(block);
+    framework::OpDesc* op_desc = op->op_desc_;
+    VLOG(3) << "tracer tracing " << op_desc->Type();
+    op_desc->InferShape(*block);
+    op_desc->InferVarType(block);
+    std::unique_ptr<framework::OperatorBase> op_base =
+        framework::OpRegistry::CreateOp(*op_desc);
+
+    *op->input_vars_ = inputs;
+    for (VarBase* input : inputs) {
+      const std::string vname = input->var_desc_->Name();
+      framework::Variable* var = scope->Var(vname);
+      input->var_ = var;
+      if (!var->IsInitialized()) {
+        framework::VarDesc* var_desc = block->FindVar(vname);
+        if (var_desc->GetType() == framework::proto::VarType::LOD_TENSOR) {
+          var->GetMutable<framework::LoDTensor>();
+        } else {
+          LOG(ERROR) << "tracer doesn't support yet";
+        }
+      }
+      if (input->pre_op_) {
+        op->pre_ops_->push_back(input->pre_op_);
+        op->pre_ops_out_idx_->push_back(input->pre_op_out_idx_);
+      } else {
+        op->pre_ops_->push_back(nullptr);
+      }
+    }
+
+    *op->output_vars_ = outputs;
+    for (size_t i = 0; i < outputs.size(); ++i) {
+      const std::string vname = outputs[i]->var_desc_->Name();
+      framework::Variable* var = scope->Var(vname);
+      if (!var->IsInitialized()) {
+        framework::VarDesc* var_desc = block->FindVar(vname);
+        if (var_desc->GetType() == framework::proto::VarType::LOD_TENSOR) {
+          var->GetMutable<framework::LoDTensor>();
+        } else {
+          LOG(ERROR) << "tracer doesn't support yet";
+        }
+      }
+      outputs[i]->var_ = var;
+      outputs[i]->pre_op_ = op;
+      outputs[i]->pre_op_out_idx_ = i;
+    }
+    op_base->Run(*scope, platform::CPUPlace());
+    framework::OpDesc* grad_op_desc;
+    auto grad_to_var = new std::unordered_map<std::string, std::string>();
+    CreateGradOp(*op_desc, {}, {block}, &grad_op_desc, grad_to_var);
+    op->grad_op_desc_ = grad_op_desc;
+    op->grad_to_var_ = grad_to_var;
+    op->block_ = block;
+  }
+
+  framework::Scope* GetScope(framework::BlockDesc* block) {
+    if (scopes_.find(block) != scopes_.end()) {
+      return scopes_.at(block);
+    }
+    framework::BlockDesc* parent_block = block->ParentBlock();
+    PADDLE_ENFORCE(scopes_.find(parent_block) != scopes_.end());
+    framework::Scope* scope = &scopes_[parent_block]->NewScope();
+    scopes_[block] = scope;
+    return scope;
+  }
+
+ private:
+  std::map<framework::BlockDesc*, framework::Scope*> scopes_;
+  framework::BlockDesc* root_block_;
+  framework::Scope* root_scope_;
+};
+
+}  // namespace imperative
+}  // namespace paddle

paddle/fluid/operators/bpr_loss_op.cc

+/* Copyright (c) 2016 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/bpr_loss_op.h"
+
+namespace paddle {
+namespace operators {
+
+class BprLossOp : public framework::OperatorWithKernel {
+ public:
+  using framework::OperatorWithKernel::OperatorWithKernel;
+
+  void InferShape(framework::InferShapeContext* ctx) const override {
+    PADDLE_ENFORCE(ctx->HasInput("X"), "Input(X) should be not null.");
+    PADDLE_ENFORCE(ctx->HasInput("Label"), "Input(Label) should be not null.");
+    PADDLE_ENFORCE(ctx->HasOutput("Y"), "Output(Y) should be not null.");
+
+    auto x_dims = ctx->GetInputDim("X");
+    auto label_dims = ctx->GetInputDim("Label");
+    int rank = x_dims.size();
+    PADDLE_ENFORCE_EQ(rank, label_dims.size(),
+                      "Input(X) and Input(Label) shall have the same rank.");
+    PADDLE_ENFORCE_EQ(framework::slice_ddim(x_dims, 0, rank - 1),
+                      framework::slice_ddim(label_dims, 0, rank - 1),
+                      "Input(X) and Input(Label) shall have the same shape "
+                      "except the last dimension.");
+
+    auto y_dims = x_dims;
+    y_dims[rank - 1] = 1;
+    ctx->SetOutputDim("Y", y_dims);
+    ctx->ShareLoD("X", /*->*/ "Y");
+  }
+
+ protected:
+  // Explicitly set that the data type of computation kernel of Seq-bpr
+  // is determined by its input "X".
+  framework::OpKernelType GetExpectedKernelType(
+      const framework::ExecutionContext& ctx) const override {
+    return framework::OpKernelType(
+        framework::ToDataType(ctx.Input<Tensor>("X")->type()),
+        platform::CPUPlace());
+  }
+};
+
+class BprLossGradientOp : public framework::OperatorWithKernel {
+ public:
+  using framework::OperatorWithKernel::OperatorWithKernel;
+
+  void InferShape(framework::InferShapeContext* ctx) const override {
+    PADDLE_ENFORCE(ctx->HasInput("X"), "Input(X) should be not null.");
+    PADDLE_ENFORCE(ctx->HasInput("Label"), "Input(Label) should be not null.");
+    PADDLE_ENFORCE(ctx->HasInput(framework::GradVarName("Y")),
+                   "Input(Y@GRAD) shoudl be not null.");
+    PADDLE_ENFORCE(ctx->HasOutput(framework::GradVarName("X")),
+                   "Output(X@GRAD) should be not null.");
+
+    auto x_dims = ctx->GetInputDim("X");
+    auto label_dims = ctx->GetInputDim("Label");
+    auto dy_dims = ctx->GetInputDim(framework::GradVarName("Y"));
+    int rank = x_dims.size();
+    PADDLE_ENFORCE_EQ(dy_dims.size(), rank,
+                      "Input(Y@Grad) and Input(X) should have the same rank.");
+    PADDLE_ENFORCE_EQ(label_dims.size(), rank,
+                      "Input(Label) and Input(X) should have the same rank.");
+    PADDLE_ENFORCE_EQ(framework::slice_ddim(x_dims, 0, rank - 1),
+                      framework::slice_ddim(label_dims, 0, rank - 1),
+                      "The Input(X) and Input(Label) should have the same "
+                      "shape except the last dimension.");
+    PADDLE_ENFORCE_EQ(framework::slice_ddim(x_dims, 0, rank - 1),
+                      framework::slice_ddim(dy_dims, 0, rank - 1),
+                      "The Input(X) and Input(Y@Grad) should have the same "
+                      "shape except the last dimension.");
+    PADDLE_ENFORCE_EQ(dy_dims[rank - 1], 1,
+                      "The last dimension of Input(Y@Grad) should be 1.");
+    PADDLE_ENFORCE_EQ(label_dims[rank - 1], 1,
+                      " the last dimension of Input(Label) should be 1.");
+    ctx->SetOutputDim(framework::GradVarName("X"), x_dims);
+    ctx->ShareLoD("X", framework::GradVarName("X"));
+  }
+
+ protected:
+  // Explicitly set that the data type of computation kernel of cross_entropy
+  // is determined by its input "X".
+  framework::OpKernelType GetExpectedKernelType(
+      const framework::ExecutionContext& ctx) const override {
+    return framework::OpKernelType(
+        framework::ToDataType(ctx.Input<Tensor>("X")->type()),
+        platform::CPUPlace());
+  }
+};
+
+class BprLossOpMaker : public framework::OpProtoAndCheckerMaker {
+ public:
+  void Make() override {
+    AddInput("X",
+             "(Tensor, default Tensor<float>), a tensor whose last dimension "
+             "size is equal to the number of classes. This input is a "
+             "real number.");
+    AddInput(
+        "Label",
+        "(Tensor), the tensor which represents the ground truth. It has the "
+        "same shape with 'X' except the last dimension. the last dimension "
+        "size is 1.");
+    AddOutput("Y",
+              "(Tensor, default Tensor<float>), a tensor whose shape is same "
+              "with 'X' except that the last dimension size is 1. It "
+              "represents the sequence bpr loss.");
+    AddComment(R"DOC(
+Bayesian Personalized Ranking Loss Operator.
+
+This operator belongs to pairwise ranking loss. Label is the desired item.
+The loss at a given point in one session is defined as:
+$Y[i] = -\frac{1}{N_{i}} * \sum_{j=0}^{N_{i}}\log(\sigma(X[i, Label[i]]-X[i, j]))$
+
+Learn more details by reading paper <session-based recommendations with recurrent
+neural networks>(https://arxiv.org/abs/1511.06939)
+
+)DOC");
+  }
+};
+}  // namespace operators
+}  // namespace paddle
+
+namespace ops = paddle::operators;
+using CPUCtx = paddle::platform::CPUDeviceContext;
+
+REGISTER_OPERATOR(bpr_loss, ops::BprLossOp, ops::BprLossOpMaker,
+                  paddle::framework::DefaultGradOpDescMaker<true>);
+REGISTER_OPERATOR(bpr_loss_grad, ops::BprLossGradientOp);
+REGISTER_OP_CPU_KERNEL(bpr_loss, ops::BprLossOpKernel<CPUCtx, float>,
+                       ops::BprLossOpKernel<CPUCtx, double>);
+REGISTER_OP_CPU_KERNEL(bpr_loss_grad,
+                       ops::BprLossGradientOpKernel<CPUCtx, float>,
+                       ops::BprLossGradientOpKernel<CPUCtx, double>);

paddle/fluid/operators/bpr_loss_op.h

+/* Copyright (c) 2016 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. */
+
+#pragma once
+#include "paddle/fluid/framework/eigen.h"
+#include "paddle/fluid/framework/op_registry.h"
+#include "paddle/fluid/operators/math/math_function.h"
+#include "paddle/fluid/platform/for_range.h"
+
+namespace paddle {
+namespace operators {
+
+using Tensor = framework::Tensor;
+/*Todo:
+ *Find a way to adapt TolerableValue, using blas or eigen.
+ */
+template <typename T>
+struct TolerableValue {
+  HOSTDEVICE T operator()(const T& x) const {
+    PADDLE_ASSERT(std::is_floating_point<T>::value);
+    const T kApproInf = 1e20;
+    if (x == INFINITY) return kApproInf;
+    if (x == -INFINITY) return -kApproInf;
+    return x;
+  }
+};
+
+template <typename DeviceContext, typename T>
+class BprLossOpKernel : public framework::OpKernel<T> {
+ public:
+  void Compute(const framework::ExecutionContext& ctx) const override {
+    auto* x = ctx.Input<Tensor>("X");
+    auto* label = ctx.Input<Tensor>("Label");
+    auto* y = ctx.Output<Tensor>("Y");
+    y->mutable_data<T>(ctx.GetPlace());
+    int rank = x->dims().size();
+
+    Tensor x_2d = framework::ReshapeToMatrix(*x, rank - 1);
+    Tensor labels_2d = framework::ReshapeToMatrix(*label, rank - 1);
+    Tensor y_2d = framework::ReshapeToMatrix(*y, rank - 1);
+
+    const framework::Tensor* logits = &x_2d;
+    const framework::Tensor* labels = &labels_2d;
+    framework::Tensor* out = &y_2d;
+
+    const int step_size = logits->dims()[0];
+    const int class_num = logits->dims()[1];
+    const T* logits_data = logits->data<T>();
+    T* loss_data = out->data<T>();
+
+    const int64_t* label_data = labels->data<int64_t>();
+    for (int i = 0; i < step_size; ++i) {
+      int lbl_pos = label_data[i];
+      PADDLE_ENFORCE_GE(lbl_pos, 0);
+      PADDLE_ENFORCE_LT(lbl_pos, class_num);
+      int index_pos = i * class_num + lbl_pos;
+      T sum = static_cast<T>(0);
+      for (int j = 0; j < class_num; j++) {
+        if (j == lbl_pos) continue;
+        int index_neg = i * class_num + j;
+        sum += TolerableValue<T>()(-std::log(
+            1.0f + TolerableValue<T>()(std::exp(logits_data[index_neg] -
+                                                logits_data[index_pos]))));
+      }
+      loss_data[i] = -sum / (class_num - 1);
+    }
+  }
+};
+
+template <typename DeviceContext, typename T>
+class BprLossGradientOpKernel : public framework::OpKernel<T> {
+ public:
+  void Compute(const framework::ExecutionContext& ctx) const override {
+    auto* x = ctx.Input<Tensor>("X");
+    auto* dy = ctx.Input<Tensor>(framework::GradVarName("Y"));
+    auto* label = ctx.Input<Tensor>("Label");
+    auto* dx = ctx.Output<Tensor>(framework::GradVarName("X"));
+
+    const int step_size = x->dims()[0];
+    const int num_classes = x->dims()[1];
+    T* dx_data = dx->mutable_data<T>(ctx.GetPlace());
+    const T* dy_data = dy->data<T>();
+    const T* x_data = x->data<T>();
+    const int64_t* label_data = label->data<int64_t>();
+
+    for (size_t sample_id = 0; sample_id < step_size; sample_id++) {
+      for (size_t x_offset = sample_id * num_classes;
+           x_offset < (sample_id + 1) * num_classes; x_offset++) {
+        dx_data[x_offset] = static_cast<T>(0);
+      }
+      auto p_index = sample_id * num_classes + label_data[sample_id];
+      for (size_t ni = 0; ni < num_classes; ni++) {
+        if (label_data[sample_id] == ni) continue;
+        auto n_index = sample_id * num_classes + ni;
+        auto grad_ = -dy_data[sample_id] /
+                     ((num_classes - 1) *
+                      (1.0f + TolerableValue<T>()(std::exp(x_data[p_index] -
+                                                           x_data[n_index]))));
+        dx_data[p_index] += grad_;
+        dx_data[n_index] -= grad_;
+      }
+    }
+  }
+};
+
+}  // namespace operators
+}  // namespace paddle

paddle/fluid/operators/split_selected_rows_op.h

@@ -72,10 +72,11 @@ class SplitSelectedRowsOpKernel : public framework::OpKernel<T> {
     for (size_t i = 0; i < outs_rows_idx.size(); ++i) {
       auto rows_idx = outs_rows_idx[i];
       outs[i]->set_height(height_sections[i]);
+      auto dims = x->GetCompleteDims();
+      dims[0] = rows_idx.size();
+      outs[i]->mutable_value()->mutable_data<T>(dims, x->place());
+      outs[i]->mutable_rows()->clear();
       if (rows_idx.size() > 0) {
-        auto dims = x->GetCompleteDims();
-        dims[0] = rows_idx.size();
-        outs[i]->mutable_value()->mutable_data<T>(dims, x->place());
         for (auto idx : rows_idx) {
           outs[i]->mutable_rows()->push_back(idx - abs_sections[i]);
         }
@@ -98,6 +99,8 @@ class SplitSelectedRowsOpKernel : public framework::OpKernel<T> {
           }
         }
       }
+      PADDLE_ENFORCE_EQ(rows_idx.size(), outs[i]->rows().size(),
+                        "rows should has the same size with tensor dim 0");
     }
   }
 };

paddle/fluid/pybind/CMakeLists.txt

 
-set(PYBIND_DEPS pybind python proto_desc memory executor async_executor prune feed_fetch_method pass_builder parallel_executor profiler)
-set(PYBIND_SRCS pybind.cc exception.cc protobuf.cc const_value.cc recordio.cc async_executor_py.cc)
+set(PYBIND_DEPS pybind python proto_desc memory executor async_executor prune feed_fetch_method pass_builder parallel_executor profiler layer)
+set(PYBIND_SRCS pybind.cc exception.cc protobuf.cc const_value.cc recordio.cc async_executor_py.cc imperative.cc)
+
 if(WITH_PYTHON)
   if(WITH_AMD_GPU)
     hip_library(paddle_pybind SHARED

paddle/fluid/pybind/imperative.cc

+/* 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/pybind/imperative.h"
+#include "paddle/fluid/framework/block_desc.h"
+#include "paddle/fluid/framework/scope.h"
+#include "paddle/fluid/imperative/tracer.h"
+
+namespace paddle {
+namespace pybind {
+
+// Bind Methods
+void BindTracer(pybind11::module *m) {
+  pybind11::class_<imperative::Tracer>(*m, "Tracer", "")
+      .def("__init__",
+           [](imperative::Tracer &self, framework::BlockDesc *root_block) {
+             new (&self) imperative::Tracer(root_block);
+           })
+      .def("trace", &imperative::Tracer::Trace)
+      .def("get_scope", &imperative::Tracer::GetScope,
+           pybind11::return_value_policy::reference);
+}
+
+}  // namespace pybind
+}  // namespace paddle

paddle/fluid/pybind/imperative.h

+/* 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. */
+#pragma once
+
+#include <Python.h>
+#include <vector>
+#include "paddle/fluid/imperative/layer.h"
+#include "pybind11/pybind11.h"
+#include "pybind11/stl.h"
+
+namespace paddle {
+namespace pybind {
+
+class PyLayer : public imperative::Layer {
+ public:
+  using imperative::Layer::Layer;  // Inherit constructors
+
+  std::vector<imperative::VarBase> Forward(
+      const std::vector<imperative::VarBase>& inputs) override {
+    PYBIND11_OVERLOAD(std::vector<imperative::VarBase>, Layer, Forward,
+                      inputs);  // NOLINT
+  }
+
+  void Backward() override {
+    PYBIND11_OVERLOAD(void, Layer, Backward, );  // NOLINT
+  }
+};
+
+class PyOpBase : public imperative::OpBase {
+ public:
+  using imperative::OpBase::OpBase;  // Inherit constructors
+};
+
+class PyVarBase : public imperative::VarBase {
+ public:
+  using imperative::VarBase::VarBase;  // Inherit constructors
+};
+
+void BindTracer(pybind11::module* m);
+
+}  // namespace pybind
+}  // namespace paddle

paddle/fluid/pybind/pybind.cc

@@ -34,6 +34,7 @@ limitations under the License. */
 #include "paddle/fluid/framework/reader.h"
 #include "paddle/fluid/framework/selected_rows.h"
 #include "paddle/fluid/framework/version.h"
+#include "paddle/fluid/imperative/layer.h"
 #include "paddle/fluid/memory/allocation/allocator_strategy.h"
 #include "paddle/fluid/operators/activation_op.h"
 #include "paddle/fluid/operators/reader/lod_tensor_blocking_queue.h"
@@ -45,6 +46,7 @@ limitations under the License. */
 #include "paddle/fluid/pybind/async_executor_py.h"
 #include "paddle/fluid/pybind/const_value.h"
 #include "paddle/fluid/pybind/exception.h"
+#include "paddle/fluid/pybind/imperative.h"
 #include "paddle/fluid/pybind/protobuf.h"
 #include "paddle/fluid/pybind/pybind.h"  // NOLINT
 #include "paddle/fluid/pybind/recordio.h"
@@ -100,6 +102,42 @@ PYBIND11_MODULE(core, m) {
 
   BindException(&m);
 
+  py::class_<imperative::VarBase, PyVarBase>(m, "VarBase", R"DOC()DOC")
+      .def(py::init<>())
+      .def("_run_backward",
+           [](imperative::VarBase &self, framework::Scope *scope) {
+             self.RunBackward(scope);
+           })
+      .def("_grad", &imperative::VarBase::Grad)
+      .def_property(
+          "desc",
+          [](const imperative::VarBase &self) { return self.var_desc_; },
+          [](imperative::VarBase &self, framework::VarDesc *var_desc) {
+            self.var_desc_ = var_desc;
+          },
+          py::return_value_policy::reference);
+
+  py::class_<imperative::OpBase, PyOpBase>(m, "OpBase", R"DOC()DOC")
+      .def(py::init<>())
+      .def_property(
+          "desc", [](const imperative::OpBase &self) { return self.op_desc_; },
+          [](imperative::OpBase &self, framework::OpDesc *op_desc) {
+            if (op_desc) {
+              self.op_desc_ = op_desc;
+            }
+          },
+          py::return_value_policy::reference);
+
+  py::class_<imperative::Layer, PyLayer /* <--- trampoline*/> layer(m, "Layer");
+  layer.def(py::init<>())
+      .def("forward",
+           [](imperative::Layer &self,
+              const std::vector<imperative::VarBase> &inputs) {
+             return self.Forward(inputs);
+           })
+      .def("backward", &imperative::Layer::Backward);
+  BindTracer(&m);
+
   py::class_<Tensor>(m, "Tensor", py::buffer_protocol())
       .def_buffer(
           [](Tensor &self) -> py::buffer_info { return CastToPyBuffer(self); })
@@ -298,6 +336,8 @@ PYBIND11_MODULE(core, m) {
       .def("get_tensor",
            [](SelectedRows &self) { return self.mutable_value(); },
            py::return_value_policy::reference)
+      .def("numel",
+           [](SelectedRows &self) -> int64_t { return self.value().numel(); })
       .def("set_height", &SelectedRows::set_height)
       .def("height", &SelectedRows::height)
       .def("set_rows",
@@ -601,6 +641,7 @@ All parameter, weight, gradient are variables in Paddle.
 
   m.def("set_feed_variable", framework::SetFeedVariable);
   m.def("get_fetch_variable", framework::GetFetchVariable);
+  m.def("get_variable_tensor", framework::GetVariableTensor);
 
   m.def("_is_program_version_supported", IsProgramVersionSupported);
 

paddle/fluid/pybind/tensor_py.h

@@ -182,7 +182,7 @@ inline void PyCPUTensorSetFromArray(
     paddle::platform::CPUPlace place) {
   std::vector<int64_t> dims;
   dims.reserve(array.ndim());
-  for (size_t i = 0; i < array.ndim(); ++i) {
+  for (int i = 0; i < array.ndim(); ++i) {
     dims.push_back(static_cast<int>(array.shape()[i]));
   }
 

python/paddle/fluid/__init__.py

@@ -34,6 +34,7 @@ from . import io
 from . import evaluator
 from . import initializer
 from . import layers
+from . import imperative
 from . import contrib
 from . import nets
 from . import optimizer
@@ -67,6 +68,7 @@ __all__ = framework.__all__ + executor.__all__ + \
         'initializer',
         'layers',
         'contrib',
+        'imperative',
         'transpiler',
         'nets',
         'optimizer',

python/paddle/fluid/average.py

@@ -48,6 +48,7 @@ class WeightedAverage(object):
 
     Examples:
         .. code-block:: python
+
             avg = fluid.average.WeightedAverage()
             avg.add(value=2.0, weight=1)
             avg.add(value=4.0, weight=2)

python/paddle/fluid/framework.py

@@ -18,6 +18,7 @@ import collections
 import contextlib
 import re
 import six
+import sys
 
 import numpy as np
 
@@ -49,6 +50,16 @@ GRAD_VAR_SUFFIX = core.kGradVarSuffix()
 ZERO_VAR_SUFFIX = core.kZeroVarSuffix()
 CONTROL_DEP_VAR_PREFIX = core.kControlDepVarName()
 
+_imperative_tracer_ = None
+
+
+def _in_imperative_mode():
+    return _imperative_tracer_ is not None
+
+
+def _imperative_tracer():
+    return _imperative_tracer_
+
 
 class NameScope(object):
     def __init__(self, name="", parent=None):
@@ -345,6 +356,21 @@ class Variable(object):
         self.op = None
         self.stop_gradient = stop_gradient
         self.is_data = is_data
+        if _in_imperative_mode():
+            self._ivar = core.VarBase()
+            self._ivar.desc = self.desc
+
+    def _numpy(self):
+        scope = _imperative_tracer().get_scope(self.block.desc)
+        tensor = core.get_variable_tensor(scope, self.desc.name())
+        return np.array(tensor)
+
+    def _backward(self):
+        scope = _imperative_tracer().get_scope(self.block.desc)
+        self._ivar._run_backward(scope)
+
+    def _gradient(self):
+        return np.array(self._ivar._grad())
 
     def __str__(self):
         return self.to_string(True)
@@ -655,6 +681,23 @@ class Operator(object):
         if self._has_kernel(type):
             self.desc.infer_var_type(self.block.desc)
             self.desc.infer_shape(self.block.desc)
+        if _in_imperative_mode():
+            self.iop = core.OpBase()
+            self.iop.desc = self.desc
+            self.inputs = []
+            if inputs is not None:
+                for inp in inputs.values():
+                    if isinstance(inp, Variable):
+                        self.inputs.append(inp)
+                    elif isinstance(inp, list) or isinstance(inp, tuple):
+                        self.inputs.extend(inp[:])
+            self.outputs = []
+            if outputs is not None:
+                for out in outputs.values():
+                    if isinstance(out, Variable):
+                        self.outputs.append(out)
+                    elif isinstance(out, list) or isinstance(out, tuple):
+                        self.outputs.extend(out[:])
 
     def _has_kernel(self, op_type):
         return op_type not in self.OP_WITHOUT_KERNEL_SET
@@ -1041,19 +1084,15 @@ class Block(object):
             raise ValueError("var %s not in this block" % name)
         return v
 
-    def _var_recursive(self, name):
+    def _find_var_recursive(self, name):
         """
         Get a Variable by name from this block recursively.
 
         Args:
             name(str): the Variable's name.
 
-        Raises:
-            ValueError: this block and this parent block doesn't
-                have a Variable with the giving name.
-
         Returns:
-            Variable: the Variable with the giving name.
+            Variable: the Variable with the giving name. Or None if not found.
         """
         frontier = list()
         visited = set()
@@ -1079,8 +1118,27 @@ class Block(object):
                 frontier.append(prog.block(cur.forward_block_idx))
 
             visited.add(id(cur))
+        return None
 
-        raise ValueError("Var {0} is not found recursively".format(name))
+    def _var_recursive(self, name):
+        """
+        Get a Variable by name from this block recursively.
+
+        Args:
+            name(str): the Variable's name.
+
+        Raises:
+            ValueError: this block and this parent block doesn't
+                have a Variable with the giving name.
+
+        Returns:
+            Variable: the Variable with the giving name.
+        """
+        var = self._find_var_recursive(name)
+        if var:
+            return var
+        else:
+            raise ValueError("Var {0} is not found recursively".format(name))
 
     def all_parameters(self):
         return list(self.iter_parameters())
@@ -1206,6 +1264,9 @@ class Block(object):
         """
         op_desc = self.desc.append_op()
         op = Operator(block=self, desc=op_desc, *args, **kwargs)
+        if _in_imperative_mode():
+            _imperative_tracer().trace(op.iop, [v._ivar for v in op.inputs],
+                                       [v._ivar for v in op.outputs], self.desc)
         self.ops.append(op)
         return op
 
@@ -2210,3 +2271,12 @@ def _get_var(name, program=None):
     assert isinstance(program, Program)
 
     return program.global_block().var(name)
+
+
+@contextlib.contextmanager
+def _imperative_guard(tracer):
+    global _imperative_tracer_
+    tmp_trace = _imperative_tracer_
+    _imperative_tracer_ = tracer
+    yield
+    _imperative_tracer_ = tmp_trace

python/paddle/fluid/imperative/__init__.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.
+
+from __future__ import print_function
+
+from . import base
+from .base import *
+
+from . import layers
+from .layers import *
+
+__all__ = []
+__all__ += layers.__all__
+__all__ += base.__all__

python/paddle/fluid/imperative/base.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 contextlib
+import numpy as np
+
+from paddle.fluid import core
+from paddle.fluid import framework
+
+__all__ = ['enabled', 'guard', 'to_variable']
+
+
+def enabled():
+    return framework._in_imperative_mode()
+
+
+@contextlib.contextmanager
+def guard():
+    train = framework.Program()
+    startup = framework.Program()
+    tracer = core.Tracer(train.current_block().desc)
+    with framework.program_guard(train, startup):
+        with framework.unique_name.guard():
+            with framework._imperative_guard(tracer):
+                yield
+
+
+def to_variable(value, block=None):
+    if isinstance(value, np.ndarray):
+        if not block:
+            block = framework.default_main_program().current_block()
+        py_var = framework.Variable(
+            block,
+            type=core.VarDesc.VarType.LOD_TENSOR,
+            name=None,
+            shape=value.shape,
+            dtype=value.dtype)
+        scope = framework._imperative_tracer().get_scope(block.desc)
+        var = scope.var(py_var.name)
+        tensor = var.get_tensor()
+        tensor.set(value, core.CPUPlace())
+        return py_var
+    elif isinstance(value, framework.Variable):
+        return value
+    else:
+        raise ValueError("Unsupported type %s" % type(value))

python/paddle/fluid/imperative/layers.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 contextlib
+import sys
+import numpy as np
+
+from paddle.fluid import core
+from paddle.fluid import framework
+from paddle.fluid.imperative import base
+
+__all__ = ['PyLayer']
+
+
+class PyLayer(core.Layer):
+    def __init__(self):
+        pass
+
+    def __call__(self, inputs):
+        # TODO(panyx0718): Support declarative mode as well.
+        assert base.enabled()
+        if not isinstance(inputs, list) and not isinstance(inputs, tuple):
+            inputs = [inputs]
+
+        var_inputs = []
+        for x in inputs:
+            py_var = base.to_variable(x)
+            var_inputs.append(py_var)
+        outputs = self.forward(var_inputs)
+        return outputs
+
+    def forward(self, inputs):
+        return []

python/paddle/fluid/layer_helper.py

@@ -17,10 +17,13 @@ from __future__ import print_function
 import copy
 import itertools
 import six
+import sys
+import numpy as np
 
 from .framework import Variable, Parameter, default_main_program, default_startup_program, dtype_is_floating
 from . import unique_name
 from paddle.fluid.initializer import Constant, Xavier
+from paddle.fluid.imperative import base
 from .param_attr import ParamAttr, WeightNormParamAttr
 from . import core
 from six.moves import zip
@@ -46,23 +49,21 @@ class LayerHelper(object):
     def startup_program(self):
         return default_startup_program()
 
+    def to_variable(self, x):
+        return base.to_variable(x, self.main_program.current_block())
+
     def append_op(self, *args, **kwargs):
         return self.main_program.current_block().append_op(*args, **kwargs)
 
     def multiple_input(self, input_param_name='input'):
         inputs = self.kwargs.get(input_param_name, [])
-        type_error = TypeError(
-            "Input of {0} layer should be Variable or sequence of Variable".
-            format(self.layer_type))
-        if isinstance(inputs, Variable):
-            inputs = [inputs]
-        elif not isinstance(inputs, list) and not isinstance(inputs, tuple):
-            raise type_error
+        ret = []
+        if isinstance(inputs, list) or isinstance(inputs, tuple):
+            for inp in inputs:
+                ret.append(self.to_variable(inp))
         else:
-            for each in inputs:
-                if not isinstance(each, Variable):
-                    raise type_error
-        return inputs
+            ret.append(self.to_variable(inputs))
+        return ret
 
     def input(self, input_param_name='input'):
         inputs = self.multiple_input(input_param_name)

python/paddle/fluid/layers/control_flow.py

@@ -717,8 +717,9 @@ class While(object):
 
         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))
+            inner_var = parent_block._find_var_recursive(inner_out_name)
+            if inner_var:
+                out_vars.append(inner_var)
 
         step_scope = parent_block.create_var(
             type=core.VarDesc.VarType.STEP_SCOPES)
@@ -1264,10 +1265,11 @@ class ConditionalBlock(object):
             if each_name not in input_set
         ]
 
-        out_list = [
-            parent_block.var(var_name) for var_name in parent_block.vars
-            if var_name in intermediate
-        ]
+        out_list = []
+        for inner_out_name in intermediate:
+            inner_var = parent_block._find_var_recursive(inner_out_name)
+            if inner_var:
+                out_list.append(inner_var)
 
         step_scope = parent_block.create_var(
             type=core.VarDesc.VarType.STEP_SCOPES)

python/paddle/fluid/layers/nn.py

@@ -41,6 +41,7 @@ __all__ = [
     'crf_decoding',
     'cos_sim',
     'cross_entropy',
+    'bpr_loss',
     'square_error_cost',
     'chunk_eval',
     'sequence_conv',
@@ -1348,6 +1349,44 @@ def cross_entropy(input, label, soft_label=False, ignore_index=kIgnoreIndex):
     return out
 
 
+def bpr_loss(input, label, name=None):
+    """
+    Bayesian Personalized Ranking Loss Operator.
+
+    This operator belongs to pairwise ranking loss. Label is the desired item.
+    The loss at a given point in one session is defined as:
+    $Y[i] = -\frac{1}{N_{i}-1} * \sum_{0\le j<N_{i},~ j\neq Label[i]}\log(\sigma(X[i, Label[i]]-X[i, j]))$
+
+    Learn more details by reading paper <session-based recommendations with recurrent
+    neural networks>(https://arxiv.org/abs/1511.06939)
+
+    Args:
+        input (Variable|list):  a 2-D tensor with shape [N x D], where N is the
+                                batch size and D is the number of classes.
+                                This input is not probability but logits.
+        label (Variable|list):  the ground truth which is a 2-D tensor.  `label`
+                                is a tensor<int64> with shape [N x 1].
+        name (str|None):        A name for this layer(optional). If set None, the
+                                layer will be named automatically. Default: None.
+    Returns:
+        A 2-D tensor with shape [N x 1], the bpr loss.
+
+    Examples:
+        .. code-block:: python
+
+          cost = fluid.layers.bpr_loss(input=predict, label=label)
+    """
+
+    helper = LayerHelper('bpr_loss', **locals())
+    out = helper.create_variable_for_type_inference(dtype=input.dtype)
+    helper.append_op(
+        type='bpr_loss',
+        inputs={'X': [input],
+                'Label': [label]},
+        outputs={'Y': [out]})
+    return out
+
+
 def square_error_cost(input, label):
     """
     **Square error cost layer**
@@ -6623,7 +6662,8 @@ def relu(x, name=None):
     helper = LayerHelper('relu', **locals())
     dtype = helper.input_dtype(input_param_name='x')
     out = helper.create_variable_for_type_inference(dtype)
-    helper.append_op(type="relu", inputs={"X": x}, outputs={"Out": out})
+    helper.append_op(
+        type="relu", inputs={"X": helper.input('x')}, outputs={"Out": out})
     return out
 
 

python/paddle/fluid/tests/unittests/test_bpr_loss_op.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.
+
+from __future__ import print_function
+
+import unittest
+import numpy as np
+from op_test import OpTest, randomize_probability
+
+
+class TestBprLossOp1(OpTest):
+    """Test BprLoss with discrete one-hot labels.
+    """
+
+    def setUp(self):
+        self.op_type = "bpr_loss"
+        batch_size = 40
+        class_num = 5
+        X = randomize_probability(batch_size, class_num, dtype='float64')
+        label = np.random.randint(0, class_num, (batch_size, 1), dtype="int64")
+        bpr_loss_result = []
+        for i in range(batch_size):
+            sum = 0.0
+            for j in range(class_num):
+                if j == label[i][0]:
+                    continue
+                sum += (-np.log(1.0 + np.exp(X[i][j] - X[i][label[i][0]])))
+            bpr_loss_result.append(-sum / (class_num - 1))
+        bpr_loss = np.asmatrix([[x] for x in bpr_loss_result], dtype="float64")
+        self.inputs = {"X": X, "Label": label}
+        self.outputs = {"Y": bpr_loss}
+
+    def test_check_output(self):
+        self.check_output()
+
+    def test_check_grad(self):
+        self.check_grad(["X"], "Y", numeric_grad_delta=0.001)
+
+
+if __name__ == "__main__":
+    unittest.main()

python/paddle/fluid/tests/unittests/test_imperative.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 unittest
+import sys
+import numpy as np
+
+import paddle.fluid as fluid
+from paddle.fluid import core
+
+
+class MyLayer(fluid.imperative.PyLayer):
+    def __init__(self):
+        super(MyLayer, self).__init__()
+
+    def forward(self, inputs):
+        x = fluid.layers.relu(inputs[0])
+        self._x_for_debug = x
+        return [fluid.layers.elementwise_mul(x, x)]
+
+
+class TestImperative(unittest.TestCase):
+    def test_layer(self):
+        with fluid.imperative.guard():
+            cl = core.Layer()
+            cl.forward([])
+            l = fluid.imperative.PyLayer()
+            l.forward([])
+
+    def test_layer_in_out(self):
+        with fluid.imperative.guard():
+            l = MyLayer()
+            x = l(np.array([1.0, 2.0, -1.0], dtype=np.float32))[0]
+            self.assertIsNotNone(x)
+            sys.stderr.write("%s output: %s\n" % (x, x._numpy()))
+            x._backward()
+            sys.stderr.write("grad %s\n" % l._x_for_debug._gradient())
+
+
+if __name__ == '__main__':
+    unittest.main()

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

@@ -846,6 +846,15 @@ class TestBook(unittest.TestCase):
             out = layers.cross_entropy(x, label, False, 4)
             self.assertIsNotNone(out)
 
+    def test_bpr_loss(self):
+        program = Program()
+        with program_guard(program):
+            x = layers.data(name="x", shape=[30, 10], dtype="float32")
+            label = layers.data(name="label", shape=[30, 1], dtype="int32")
+            out = layers.bpr_loss(x, label)
+            self.assertIsNotNone(out)
+        print(str(program))
+
     def test_expand(self):
         program = Program()
         with program_guard(program):

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

@@ -22,6 +22,15 @@ from paddle.fluid.framework import Program, program_guard
 from paddle.fluid.transpiler import memory_optimize
 
 
+def _get_vars(prog):
+    assert (isinstance(prog, Program))
+    all_vars = set()
+    for op in prog.global_block().ops:
+        all_vars.update(op.input_arg_names)
+        all_vars.update(op.output_arg_names)
+    return all_vars
+
+
 class TestControlFlowGraph(unittest.TestCase):
     def setUp(self):
         program = Program()
@@ -37,11 +46,11 @@ class TestControlFlowGraph(unittest.TestCase):
         self.program = program
 
     def test_control_flow_graph(self):
-        print("before optimization")
-        print(str(self.program))
-        result_program = memory_optimize(self.program)
-        print("after optimization")
-        print(str(result_program))
+        result_program = self.program.clone()
+        memory_optimize(self.program)
+        old_vars = _get_vars(self.program)
+        new_vars = _get_vars(result_program)
+        self.assertTrue(old_vars != new_vars)
 
 
 class TestMemoryTranspiler2(unittest.TestCase):
@@ -58,14 +67,22 @@ class TestMemoryTranspiler2(unittest.TestCase):
             avg_cost = layers.mean(cost)
             opt = optimizer.SGD(learning_rate=0.001)
             opt.minimize(avg_cost)
+        self.skip_set = set([cost.name, fc.name])
         self.program = program
 
     def test_inplace_ops(self):
-        print("before optimization")
-        print(str(self.program))
-        result_program = memory_optimize(self.program)
-        print("after optimization")
-        print(str(result_program))
+        result_program = self.program.clone()
+        memory_optimize(self.program)
+        old_vars = _get_vars(self.program)
+        new_vars = _get_vars(result_program)
+        self.assertTrue(old_vars != new_vars)
+
+    def test_skip_opt(self):
+        result_program = self.program.clone()
+        memory_optimize(self.program, skip_opt_set=self.skip_set)
+        old_vars = _get_vars(self.program)
+        new_vars = _get_vars(result_program)
+        self.assertTrue(old_vars != new_vars)
 
 
 class TestMemoryTranspiler3(unittest.TestCase):

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

@@ -63,6 +63,7 @@ class TestSpliteSelectedRows(unittest.TestCase):
         # expected output selected rows
         expected_out0_rows = [0, 4]
         expected_out1_rows = [0, 2]
+        expected_out2_rows = []
         expected_out4_rows = [0]
 
         op = Operator(
@@ -75,6 +76,7 @@ class TestSpliteSelectedRows(unittest.TestCase):
 
         self.assertEqual(outs[0].rows(), expected_out0_rows)
         self.assertEqual(outs[1].rows(), expected_out1_rows)
+        self.assertEqual(outs[2].rows(), expected_out2_rows)
         self.assertEqual(outs[4].rows(), expected_out4_rows)
 
         self.assertEqual(outs[0].height(), height_sections[0])
@@ -84,6 +86,9 @@ class TestSpliteSelectedRows(unittest.TestCase):
         self.assertAlmostEqual(4.0, np.array(outs[1].get_tensor())[1, 1])
         self.assertAlmostEqual(8.0, np.array(outs[4].get_tensor())[0, 1])
 
+        self.assertEqual(outs[2].numel(), 0)
+        self.assertEqual(outs[3].numel(), 0)
+
     def check_grad_with_place(self, place):
         scope = core.Scope()
         height = 10

python/paddle/fluid/transpiler/memory_optimization_transpiler.py

@@ -14,6 +14,7 @@
 
 from __future__ import print_function
 
+import six
 from collections import defaultdict, MutableSet
 from .. import core
 from ... import compat as cpt
@@ -470,8 +471,21 @@ def memory_optimize(input_program,
     Returns:
         None
     """
+
+    def to_name_str(var):
+        if isinstance(var, Variable):
+            return var.desc.name()
+        elif isinstance(var, str):
+            return var
+        elif isinstance(var, six.string_types):
+            return str(var)
+        else:
+            raise TypeError(str(var) + " should be Variable or str")
+
     if level != 0 and level != 1:
         raise ValueError("only support opt_level 0 or 1.")
+    if skip_opt_set is not None and not isinstance(skip_opt_set, set):
+        raise ValueError("only support skip_opt_set as set.")
     global PRINT_LOG
     PRINT_LOG = print_log
     if skip_grads:
@@ -486,6 +500,8 @@ def memory_optimize(input_program,
             skip_opt_set = grad_set
         else:
             skip_opt_set.update(grad_set)
+    if skip_opt_set is not None:
+        skip_opt_set = set(map(to_name_str, skip_opt_set))
     cfgs = _get_cfgs(input_program)
     for cfg in cfgs:
         cfg.memory_optimize(skip_opt_set=skip_opt_set, level=level)

python/setup.py.in

@@ -101,6 +101,7 @@ packages=['paddle',
           'paddle.dataset',
           'paddle.reader',
           'paddle.fluid',
+          'paddle.fluid.imperative',
           'paddle.fluid.proto',
           'paddle.fluid.proto.profiler',
           'paddle.fluid.layers',

tools/print_signatures.py

@@ -27,6 +27,8 @@ import pydoc
 
 member_dict = collections.OrderedDict()
 
+experimental_namespace = {"paddle.fluid.imperative"}
+
 
 def visit_member(parent_name, member):
     cur_name = ".".join([parent_name, member.__name__])
@@ -51,6 +53,8 @@ def visit_member(parent_name, member):
 
 
 def visit_all_module(mod):
+    if (mod.__name__ in experimental_namespace):
+        return
     for member_name in (
             name
             for name in (mod.__all__ if hasattr(mod, "__all__") else dir(mod))