diff --git a/paddle/CMakeLists.txt b/paddle/CMakeLists.txt
index 2c1eb7521d896e6d67021e4d020f274bb32d123c..58a35564f83928ee0bdaad63b154ed57d8d8a735 100644
--- a/paddle/CMakeLists.txt
+++ b/paddle/CMakeLists.txt
@@ -15,7 +15,6 @@ if(Boost_FOUND)
   add_subdirectory(memory)
   add_subdirectory(platform)
   add_subdirectory(framework)
-  add_subdirectory(operators)
   add_subdirectory(pybind)
 endif()
 
diff --git a/paddle/framework/dim.h b/paddle/framework/dim.h
index bcde291d12d429a3f2cd41fa6d0ee606c7c9c92f..883fdc55eb929ebc51e8ae05938e9d07374406ce 100644
--- a/paddle/framework/dim.h
+++ b/paddle/framework/dim.h
@@ -266,29 +266,6 @@ HOSTDEVICE inline bool contained(const Dim<1>& idx, const Dim<1>& size) {
   return ((0 <= idx.head) && (idx.head < size.head));
 }
 
-/**
- * \brief Check if a size and a stride create a Fortran order contiguous
- * block of memory.
- */
-template <int i>
-HOST bool contiguous(const Dim<i>& size, const Dim<i>& stride, int mul = 1) {
-  if (product(size) == 0) return true;
-  int contiguous_stride = get<0>(size) == 1 ? 0 : mul;
-  return (get<0>(stride) == contiguous_stride &&
-          contiguous(size.tail, stride.tail, mul * get<0>(size)));
-}
-
-///\cond HIDDEN
-// Base case of contiguous, check the nth stride is the size of
-// the prefix multiply of n-1 dims.
-template <>
-inline bool contiguous(const Dim<1>& size, const Dim<1>& stride, int mul) {
-  if (get<0>(size) == 0) return true;
-  int contiguous_stride = get<0>(size) == 1 ? 0 : mul;
-  return get<0>(stride) == contiguous_stride;
-}
-///\endcond
-
 /**
  * \brief Compute exclusive prefix-multiply of a Dim.
  */
@@ -306,31 +283,6 @@ HOSTDEVICE inline Dim<1> ex_prefix_mul(const Dim<1>& src, int mul) {
 }
 ///\endcond
 
-/**
- * \brief Calculate strides of a contiguous array of the given size
- *
- * Sets the stride for any dimension with an extent of 1 to 0.
- * \param size Dim object containing the size of the array.
- * \param base The base stride to use.
- * \return Dim object the same size as \p size with the strides.
- */
-template <int i>
-HOSTDEVICE Dim<i> contiguous_strides(const Dim<i>& size, int base = 1) {
-  int stride = size.head == 1 ? 0 : base;
-  return Dim<i>(stride, contiguous_strides(size.tail, base * size.head));
-}
-
-///\cond HIDDEN
-
-// Base case of contiguous_strides
-template <>
-HOSTDEVICE inline Dim<1> contiguous_strides(const Dim<1>& size, int base) {
-  int stride = size.head == 1 ? 0 : base;
-  return Dim<1>(stride);
-}
-
-///\endcond
-
 /**
  * Add two dimensions together
  */
diff --git a/paddle/framework/dim_test.cu b/paddle/framework/dim_test.cu
index 809bf04826637195425a32c054c94e00ef940df9..05217415196f3ec3ce9b5de7cb2f82c9de960ba7 100644
--- a/paddle/framework/dim_test.cu
+++ b/paddle/framework/dim_test.cu
@@ -58,24 +58,6 @@ TEST(Dim, Equality) {
     EXPECT_EQ(paddle::framework::get<1>(c), 3);
     EXPECT_EQ(paddle::framework::get<2>(c), 12);
 
-    // contiguous_strides
-    c = paddle::framework::contiguous_strides(paddle::framework::Dim<3>(10, 1, 10));
-    EXPECT_EQ(paddle::framework::get<0>(c), 1);
-    EXPECT_EQ(paddle::framework::get<1>(c), 0);
-    EXPECT_EQ(paddle::framework::get<2>(c), 10);
-    c = paddle::framework::contiguous_strides(paddle::framework::Dim<3>(10, 10, 1));
-    EXPECT_EQ(paddle::framework::get<0>(c), 1);
-    EXPECT_EQ(paddle::framework::get<1>(c), 10);
-    EXPECT_EQ(paddle::framework::get<2>(c), 0);
-    c = paddle::framework::contiguous_strides(paddle::framework::Dim<3>(1, 10, 10));
-    EXPECT_EQ(paddle::framework::get<0>(c), 0);
-    EXPECT_EQ(paddle::framework::get<1>(c), 1);
-    EXPECT_EQ(paddle::framework::get<2>(c), 10);
-    c = paddle::framework::contiguous_strides(paddle::framework::Dim<3>(2, 3, 4));
-    EXPECT_EQ(paddle::framework::get<0>(c), 1);
-    EXPECT_EQ(paddle::framework::get<1>(c), 2);
-    EXPECT_EQ(paddle::framework::get<2>(c), 6);
-
     // generate from an index
     auto size = paddle::framework::make_dim(4, 5, 2);
     c = paddle::framework::Dim<3>(14, size);
@@ -101,16 +83,6 @@ TEST(Dim, Bool) {
     EXPECT_TRUE(a == a);
     EXPECT_FALSE(a == b);
     EXPECT_TRUE(a == c);
-
-    // contiguous check
-    int x = 4, y = 5, z = 2;
-    paddle::framework::Dim<3> sizef(x, y, z);
-    paddle::framework::Dim<3> stridea(1, x, x*y);
-    paddle::framework::Dim<3> strideb(2, 2*x, 2*x*y);
-    paddle::framework::Dim<3> stridec(1, x, 2*x*y);
-    EXPECT_TRUE(paddle::framework::contiguous(sizef, stridea));
-    EXPECT_FALSE(paddle::framework::contiguous(sizef, strideb));
-    EXPECT_FALSE(paddle::framework::contiguous(sizef, stridec));
 }
 
 TEST(Dim, Print) {
diff --git a/paddle/framework/op_registry_test.cc b/paddle/framework/op_registry_test.cc
index c4baafc2aebc8d009a388635bbab180d86a4b914..f5d45a80bb8e9fa095e7d6adc6370918b3f87f5a 100644
--- a/paddle/framework/op_registry_test.cc
+++ b/paddle/framework/op_registry_test.cc
@@ -1,17 +1,15 @@
 #include "paddle/framework/op_registry.h"
 #include <gtest/gtest.h>
-#include "paddle/framework/operator.h"
-#include "paddle/operators/demo_op.h"
 
 using namespace paddle::framework;
 
 namespace paddle {
 namespace framework {
-class CosineOp : public OperatorWithKernel {
+class CosineOp : public OperatorBase {
  public:
-  void Run(const OpRunContext* context) const override {
-    printf("%s\n", DebugString().c_str());
-  }
+  void Run(const std::shared_ptr<Scope>& scope,
+           const platform::DeviceContext& dev_ctx) const override {}
+  void InferShape(const std::shared_ptr<Scope>& scope) const override {}
 };
 
 class CosineOpProtoAndCheckerMaker : public OpProtoAndCheckerMaker {
@@ -30,12 +28,13 @@ class CosineOpProtoAndCheckerMaker : public OpProtoAndCheckerMaker {
 
 REGISTER_OP(CosineOp, CosineOpProtoAndCheckerMaker, cos_sim)
 
-class MyTestOp : public OperatorWithKernel {
+class MyTestOp : public OperatorBase {
+ public:
+  void InferShape(const std::shared_ptr<Scope>& scope) const override {}
+  void Run(const std::shared_ptr<Scope>& scope,
+           const platform::DeviceContext& dev_ctx) const override {}
+
  public:
-  void Run(const OpRunContext* ctx) const override {
-    printf("%s\n", DebugString().c_str());
-    printf("test_attr = %d\n", ctx->op_->GetAttr<int>("test_attr"));
-  }
 };
 
 class MyTestOpProtoAndCheckerMaker : public OpProtoAndCheckerMaker {
@@ -73,8 +72,8 @@ TEST(OpRegistry, CreateOp) {
   paddle::framework::OperatorBase* op =
       paddle::framework::OpRegistry::CreateOp(op_desc);
   auto scope = std::make_shared<Scope>();
-  auto dev_ctx = DeviceContext();
-  op->Run(scope, &dev_ctx);
+  paddle::platform::CPUDeviceContext dev_ctx;
+  op->Run(scope, dev_ctx);
   float scale_get = op->GetAttr<float>("scale");
   ASSERT_EQ(scale_get, scale);
 }
@@ -116,8 +115,8 @@ TEST(OpRegistry, DefaultValue) {
   paddle::framework::OperatorBase* op =
       paddle::framework::OpRegistry::CreateOp(op_desc);
   auto scope = std::make_shared<Scope>();
-  auto dev_ctx = DeviceContext();
-  op->Run(scope, &dev_ctx);
+  paddle::platform::CPUDeviceContext dev_ctx;
+  op->Run(scope, dev_ctx);
   ASSERT_EQ(op->GetAttr<float>("scale"), 1.0);
 }
 
@@ -169,9 +168,9 @@ TEST(OpRegistry, CustomChecker) {
   attr->set_i(4);
   paddle::framework::OperatorBase* op =
       paddle::framework::OpRegistry::CreateOp(op_desc);
-  auto dev_ctx = DeviceContext();
+  paddle::platform::CPUDeviceContext dev_ctx;
   auto scope = std::make_shared<Scope>();
-  op->Run(scope, &dev_ctx);
+  op->Run(scope, dev_ctx);
   int test_attr = op->GetAttr<int>("test_attr");
   ASSERT_EQ(test_attr, 4);
 }
diff --git a/paddle/framework/operator.cc b/paddle/framework/operator.cc
index 3db3706e47dfab49f54b3f1f9f2e41c53fc3f298..8f7adff8b3982e91a3d7f6d598cd62d5005d5f17 100644
--- a/paddle/framework/operator.cc
+++ b/paddle/framework/operator.cc
@@ -39,13 +39,5 @@ std::string OperatorBase::DebugString() const {
   return ss.str();
 }
 
-const Variable* OpRunContext::Input(int index) const {
-  return scope_->GetVariable(op_->inputs_[index]);
-}
-
-Variable* OpRunContext::Output(int index) const {
-  return scope_->GetVariable(op_->outputs_[index]);
-}
-
 }  // namespace framework
 }  // namespace paddle
\ No newline at end of file
diff --git a/paddle/framework/operator.h b/paddle/framework/operator.h
index 6570d5869814a198195968606d041055e847ca08..0ce422e007c39ce0c3f5f7a89650cc211919ea8f 100644
--- a/paddle/framework/operator.h
+++ b/paddle/framework/operator.h
@@ -14,44 +14,22 @@ limitations under the License. */
 
 #pragma once
 
+#include <paddle/framework/attr_checker.h>
+#include <paddle/framework/op_desc.pb.h>
+#include <paddle/framework/scope.h>
+#include <paddle/platform/device_context.h>
+#include <paddle/platform/place.h>
+#include <paddle/utils/Error.h>
 #include <boost/variant.hpp>
 #include <string>
 #include <unordered_map>
 #include <vector>
 
-#include "paddle/framework/attr_checker.h"
-#include "paddle/framework/op_desc.pb.h"
-#include "paddle/framework/scope.h"
-#include "paddle/utils/Error.h"
-
 namespace paddle {
 namespace framework {
 
 class OperatorBase;
 
-class DeviceContext {};
-
-/**
- * OpRunContext is the only parameter of Operator's Run function.
- * Run will get input/output variables, state such as momentum and
- * device resource such as CUDA stream, cublas handle, etc. from
- * OpRunContext. User should construct it before run the Operator.
- */
-class OpRunContext {
- public:
-  OpRunContext(const OperatorBase* op, const std::shared_ptr<Scope> scope,
-               const DeviceContext* device_context)
-      : op_(op), scope_(scope), device_context_(device_context) {}
-
-  const Variable* Input(int index) const;
-  Variable* Output(int index) const;
-
- public:
-  const OperatorBase* op_;
-  const std::shared_ptr<Scope> scope_;
-  const DeviceContext* device_context_;
-};
-
 /**
  * OperatorBase has the basic element that Net will call to do computation.
  * Only CreateOperator from OpRegistry will new Operator directly. User
@@ -77,7 +55,10 @@ class OperatorBase {
 
   /// Net will call this function to Run an op.
   virtual void Run(const std::shared_ptr<Scope>& scope,
-                   const DeviceContext* dev_ctx) const = 0;
+                   const platform::DeviceContext& dev_ctx) const = 0;
+
+ protected:
+  std::string Type() const { return desc_.type(); }
 
  public:
   OpDesc desc_;
@@ -86,22 +67,84 @@ class OperatorBase {
   AttributeMap attrs_;
 };
 
+class OpKernel {
+ public:
+  /**
+   * KernelContext is the only parameter of Kernel Run function.
+   * Run will get input/output variables, state such as momentum and
+   * device resource such as CUDA stream, cublas handle, etc. from
+   * KernelContext. User should construct it before run the Operator.
+   */
+  class KernelContext {
+   public:
+    KernelContext(const OperatorBase* op, const std::shared_ptr<Scope>& scope,
+                  const platform::DeviceContext& device_context)
+        : op_(*op), scope_(scope), device_context_(device_context) {}
+
+    const Variable* Input(int index) const {
+      return scope_->GetVariable(op_.inputs_[index]);
+    }
+
+    Variable* Output(int index) const {
+      return scope_->GetVariable(op_.outputs_[index]);
+    }
+
+    const OperatorBase& op_;
+    const std::shared_ptr<Scope>& scope_;
+    const platform::DeviceContext& device_context_;
+  };
+
+  virtual void Compute(const KernelContext& context) const = 0;
+
+  virtual ~OpKernel() {}
+};
+
 class OperatorWithKernel : public OperatorBase {
  public:
-  virtual ~OperatorWithKernel() {}
+  struct OpKernelKey {
+    platform::Place place_;
 
-  virtual void InferShape(const std::shared_ptr<Scope>& scope) const {}
+    OpKernelKey() = default;
+    OpKernelKey(const platform::DeviceContext& dev_ctx) {
+      place_ = dev_ctx.GetPlace();
+    }
+
+    bool operator==(const OpKernelKey& o) const { return place_ == o.place_; }
+  };
+
+  struct OpKernelHash {
+    std::hash<bool> hash_;
+    size_t operator()(const OpKernelKey& key) const {
+      return hash_(platform::is_gpu_place(key.place_));
+    }
+  };
+
+  using OpKernelMap =
+      std::unordered_map<OpKernelKey, std::unique_ptr<OpKernel>, OpKernelHash>;
 
   void Run(const std::shared_ptr<Scope>& scope,
-           const DeviceContext* dev_ctx) const {
-    OpRunContext op_ctx(this, scope, dev_ctx);
-    Run(&op_ctx);
+           const platform::DeviceContext& dev_ctx) const final {
+    auto& opKernel = AllOpKernels().at(Type()).at(OpKernelKey(dev_ctx));
+    opKernel->Compute(OpKernel::KernelContext(this, scope, dev_ctx));
   }
 
-  /// when implement an Op, your should implement this function.
-  /// this function should be moved to OpKernel later
-  virtual void Run(const OpRunContext* context) const = 0;
+  static std::unordered_map<std::string /* op_type */, OpKernelMap>&
+  AllOpKernels() {
+    static std::unordered_map<std::string, OpKernelMap> g_all_op_kernels;
+    return g_all_op_kernels;
+  };
 };
 
 }  // namespace framework
 }  // namespace paddle
+
+#define REGISTER_OP_KERNEL(type, PlaceType, KernelType)                   \
+  struct __op_kernel_register__##type##__ {                               \
+    __op_kernel_register__##type##__() {                                  \
+      ::paddle::framework::OperatorWithKernel::OpKernelKey key;           \
+      key.place_ = PlaceType();                                           \
+      ::paddle::framework::OperatorWithKernel::AllOpKernels()[#type][key] \
+          .reset(new KernelType());                                       \
+    }                                                                     \
+  };                                                                      \
+  static __op_kernel_register__##type##__ __reg_kernel_##type##__
diff --git a/paddle/framework/operator_test.cc b/paddle/framework/operator_test.cc
index 48808dabb2711936550d04cb49003e87663d3d27..86f45f108a5d2189894fd59483a84b039a010ab3 100644
--- a/paddle/framework/operator_test.cc
+++ b/paddle/framework/operator_test.cc
@@ -19,17 +19,15 @@ limitations under the License. */
 namespace paddle {
 namespace framework {
 
-class OperatorTest : public OperatorWithKernel {
+class OperatorTest : public OperatorBase {
  public:
-  void Run(const OpRunContext* ctx) const override {
-    float scale = ctx->op_->GetAttr<float>("scale");
-    PADDLE_ENFORCE(ctx->Input(0) == nullptr, "Input(0) should not initialized");
-    PADDLE_ENFORCE(ctx->Output(0) == nullptr,
-                   "Output(1) should not initialized");
-    auto output1 = ctx->scope_->CreateVariable("output1");
-    PADDLE_ENFORCE(output1 != nullptr, "should create output1 from scope");
-    printf("get attr %s = %f\n", "scale", scale);
-    printf("%s\n", DebugString().c_str());
+  void InferShape(const std::shared_ptr<Scope>& scope) const override {}
+  void Run(const std::shared_ptr<Scope>& scope,
+           const platform::DeviceContext& dev_ctx) const override {
+    float scale = GetAttr<float>("scale");
+    ASSERT_NEAR(scale, 3.14, 1e-5);
+    ASSERT_EQ(scope->GetVariable(inputs_[0]), nullptr);
+    ASSERT_NE(scope->GetVariable(outputs_[0]), nullptr);
   }
 };
 
@@ -49,31 +47,26 @@ class OperatorTestProtoAndCheckerMaker : public OpProtoAndCheckerMaker {
 
 REGISTER_OP(OperatorTest, OperatorTestProtoAndCheckerMaker, test_operator)
 
-TEST(OperatorBase, DebugString) {
+TEST(OperatorBase, all) {
   OpDesc op_desc;
   op_desc.set_type("test_operator");
-  std::vector<std::string> inputs = {"IN1", "IN2"};
-  for (auto& input : inputs) {
-    op_desc.add_inputs(input);
-  }
-  std::vector<std::string> outputs = {"OUT1", "OUT2"};
-  for (auto& output : outputs) {
-    op_desc.add_outputs(output);
-  }
+  *op_desc.mutable_inputs()->Add() = "IN1";
+  *op_desc.mutable_outputs()->Add() = "OUT1";
   auto attr = op_desc.mutable_attrs()->Add();
   attr->set_name("scale");
   attr->set_type(paddle::framework::AttrType::FLOAT);
   float scale = 3.14;
   attr->set_f(scale);
 
-  DeviceContext device_context;
+  platform::CPUDeviceContext device_context;
   auto scope = std::make_shared<Scope>();
 
   OperatorBase* op = paddle::framework::OpRegistry::CreateOp(op_desc);
-  ASSERT_EQ(op->inputs_, inputs);
-  ASSERT_EQ(op->outputs_, outputs);
   ASSERT_EQ(op->GetAttr<float>("scale"), scale);
-  op->Run(scope, &device_context);
+  scope->CreateVariable("OUT1");
+  op->Run(scope, device_context);
+  std::cout << op->DebugString() << std::endl;
+  delete op;
 }
 
 }  // namespace framework
diff --git a/paddle/framework/tensor.h b/paddle/framework/tensor.h
index ce5d98b04e6b53fcedc4fc4610d9390e64846b2a..a0945e8055625ca4c21ea1c3fa9f27321ca9ba3c 100644
--- a/paddle/framework/tensor.h
+++ b/paddle/framework/tensor.h
@@ -14,6 +14,7 @@ limitations under the License. */
 
 #pragma once
 
+#include <cstdint>
 #include <memory>
 #include <type_traits>
 #include "paddle/framework/ddim.h"
@@ -26,31 +27,65 @@ namespace framework {
 
 class Tensor {
  public:
+  Tensor() : offset_(0) {}
+
+  explicit Tensor(const DDim& dims) : dims_(dims), offset_(0) {}
+
   template <typename T>
   const T* data() const {
-    PADDLE_ENFORCE(holder_ != nullptr,
-                   "Tensor::data must be called after Tensor::mutable_data.");
-    return static_cast<const T*>(holder_->Ptr());
+    PADDLE_ENFORCE(
+        holder_ != nullptr,
+        "Tenosr has not been initialized. Call Tensor::mutable_data first.");
+    return reinterpret_cast<const T*>(
+        reinterpret_cast<uintptr_t>(holder_->Ptr()) + offset_);
   }
 
   template <typename T,  // must be POD types
             typename std::enable_if<std::is_pod<T>::value>::type* = nullptr>
   T* mutable_data(DDim dims, paddle::platform::Place place) {
+    dims_ = dims;
     if (holder_ == nullptr ||
         !(holder_->Place() ==
           place) /* some versions of boost::variant don't have operator!= */
-        || holder_->Size() < product(dims) * sizeof(T)) {
+        || holder_->Size() < product(dims) * sizeof(T) + offset_) {
       holder_.reset(new PlaceholderImpl<T>(place, product(dims) * sizeof(T)));
+      offset_ = 0;
     }
-    return static_cast<T*>(holder_->Ptr());
+    return reinterpret_cast<T*>(reinterpret_cast<uintptr_t>(holder_->Ptr()) +
+                                offset_);
   }
 
-  template <typename T,  // must be POD types
-            typename std::enable_if<std::is_pod<T>::value>::type* = nullptr>
-  T* mutable_data(DDim dims) {
-    return mutable_data<T>(dims, paddle::platform::get_place());
+  void ShareDataFrom(const Tensor& src) {
+    PADDLE_ENFORCE(src.holder_ != nullptr,
+                   "Can not share data from an uninitialized tensor.");
+    holder_ = src.holder_;
+    dims_ = src.dims_;
+    offset_ = src.offset_;
   }
 
+  Tensor Slice(const int& begin_idx, const int& end_idx) const {
+    PADDLE_ENFORCE(holder_ != nullptr,
+                   "The sliced tenosr has not been initialized.");
+    PADDLE_ENFORCE(begin_idx >= 0 && end_idx <= dims_[0],
+                   "Slice index is less than zero or out of bound.");
+    PADDLE_ENFORCE(begin_idx < end_idx,
+                   "Begin index must be less than end index.");
+    PADDLE_ENFORCE(dims_[0] != 1, "Can not slice a tensor with dims_[0] = 1.");
+    std::vector<int> d = vectorize(dims_);
+    int base = 1;
+    for (size_t i = 1; i < d.size(); ++i) {
+      base *= d[i];
+    }
+    Tensor dst;
+    dst.holder_ = holder_;
+    dst.dims_ = dims_;
+    dst.dims_[0] = end_idx - begin_idx;
+    dst.offset_ = offset_ + begin_idx * base * holder_->TypeSize();
+    return dst;
+  }
+
+  DDim dims() const { return dims_; }
+
  private:
   // Placeholder hides type T, so it doesn't appear as a template
   // parameter of Variable.
@@ -59,6 +94,7 @@ class Tensor {
     virtual void* Ptr() const = 0;
     virtual paddle::platform::Place Place() const = 0;
     virtual size_t Size() const = 0;
+    virtual size_t TypeSize() const = 0;
   };
 
   template <typename T>
@@ -85,6 +121,7 @@ class Tensor {
     virtual void* Ptr() const { return static_cast<void*>(ptr_.get()); }
     virtual size_t Size() const { return size_; }
     virtual paddle::platform::Place Place() const { return place_; }
+    virtual size_t TypeSize() const { return sizeof(T); }
 
     std::unique_ptr<T, Deleter> ptr_;
     paddle::platform::Place place_;  // record the place of ptr_.
@@ -92,6 +129,8 @@ class Tensor {
   };
 
   std::shared_ptr<Placeholder> holder_;  // holds the memory block if allocated.
+  DDim dims_;
+  size_t offset_;  // marks the begin of tensor data area.
 };
 
 }  // namespace framework
diff --git a/paddle/framework/tensor_test.cc b/paddle/framework/tensor_test.cc
index 727d81f8d72e39ec564c42a48bf7ff64204adfff..f4822838cfbd27656232a23b14f716f2fbe510e0 100644
--- a/paddle/framework/tensor_test.cc
+++ b/paddle/framework/tensor_test.cc
@@ -15,15 +15,27 @@
 #include <gtest/gtest.h>
 #include <string>
 
-TEST(Tensor, ASSERT) {
-  paddle::framework::Tensor cpu_tensor;
+TEST(Tensor, Dims) {
+  using namespace paddle::framework;
+  using namespace paddle::platform;
+  Tensor tt(make_ddim({2, 3, 4}));
+  DDim dims = tt.dims();
+  ASSERT_EQ(arity(dims), 3);
+  for (int i = 0; i < 3; ++i) {
+    EXPECT_EQ(i + 2, dims[i]);
+  }
+}
+
+TEST(Tensor, DataAssert) {
+  paddle::framework::Tensor src_tensor;
 
   bool caught = false;
   try {
-    const double* p __attribute__((unused)) = cpu_tensor.data<double>();
+    src_tensor.data<double>();
   } catch (paddle::framework::EnforceNotMet err) {
     caught = true;
-    std::string msg = "Tensor::data must be called after Tensor::mutable_data.";
+    std::string msg =
+        "Tenosr has not been initialized. Call Tensor::mutable_data first.";
     const char* what = err.what();
     for (size_t i = 0; i < msg.length(); ++i) {
       ASSERT_EQ(what[i], msg[i]);
@@ -32,54 +44,138 @@ TEST(Tensor, ASSERT) {
   ASSERT_TRUE(caught);
 }
 
-/* mutable_data() is not tested at present
+/* following tests are not available at present
    because Memory::Alloc() and Memory::Free() have not been ready.
 
 TEST(Tensor, MutableData) {
   using namespace paddle::framework;
   using namespace paddle::platform;
   {
-    Tensor cpu_tensor;
+    Tensor src_tensor;
     float* p1 = nullptr;
     float* p2 = nullptr;
     // initialization
-    p1 = cpu_tensor.mutable_data<float>(make_ddim({1, 2, 3}), CPUPlace());
+    p1 = src_tensor.mutable_data<float>(make_ddim({1, 2, 3}), CPUPlace());
     EXPECT_NE(p1, nullptr);
-    // set cpu_tensor a new dim with large size
+    // set src_tensor a new dim with large size
     // momery is supposed to be re-allocated
-    p2 = cpu_tensor.mutable_data<float>(make_ddim({3, 4}));
+    p2 = src_tensor.mutable_data<float>(make_ddim({3, 4}), CPUPlace());
     EXPECT_NE(p2, nullptr);
     EXPECT_NE(p1, p2);
-    // set cpu_tensor a new dim with same size
+    // set src_tensor a new dim with same size
     // momery block is supposed to be unchanged
-    p1 = cpu_tensor.mutable_data<float>(make_ddim({2, 2, 3}));
+    p1 = src_tensor.mutable_data<float>(make_ddim({2, 2, 3}), CPUPlace());
     EXPECT_EQ(p1, p2);
-    // set cpu_tensor a new dim with smaller size
+    // set src_tensor a new dim with smaller size
     // momery block is supposed to be unchanged
-    p2 = cpu_tensor.mutable_data<float>(make_ddim({2, 2}));
+    p2 = src_tensor.mutable_data<float>(make_ddim({2, 2}), CPUPlace());
     EXPECT_EQ(p1, p2);
   }
 
   {
-    Tensor gpu_tensor;
+    Tensor src_tensor;
     float* p1 = nullptr;
     float* p2 = nullptr;
     // initialization
-    p1 = gpu_tensor.mutable_data<float>(make_ddim({1, 2, 3}), GPUPlace());
+    p1 = src_tensor.mutable_data<float>(make_ddim({1, 2, 3}), GPUPlace());
     EXPECT_NE(p1, nullptr);
-    // set gpu_tensor a new dim with large size
+    // set src_tensor a new dim with large size
     // momery is supposed to be re-allocated
-    p2 = gpu_tensor.mutable_data<float>(make_ddim({3, 4}));
+    p2 = src_tensor.mutable_data<float>(make_ddim({3, 4}), GPUPlace());
     EXPECT_NE(p2, nullptr);
     EXPECT_NE(p1, p2);
-    // set gpu_tensor a new dim with same size
+    // set src_tensor a new dim with same size
     // momery block is supposed to be unchanged
-    p1 = gpu_tensor.mutable_data<float>(make_ddim({2, 2, 3}));
+    p1 = src_tensor.mutable_data<float>(make_ddim({2, 2, 3}), GPUPlace());
     EXPECT_EQ(p1, p2);
-    // set gpu_tensor a new dim with smaller size
+    // set src_tensor a new dim with smaller size
     // momery block is supposed to be unchanged
-    p2 = gpu_tensor.mutable_data<float>(make_ddim({2, 2}));
+    p2 = src_tensor.mutable_data<float>(make_ddim({2, 2}), GPUPlace());
     EXPECT_EQ(p1, p2);
   }
 }
-*/
+
+TEST(Tensor, ShareDataFrom) {
+  using namespace paddle::framework;
+  using namespace paddle::platform;
+  {
+    Tensor src_tensor;
+    Tensor dst_tensor;
+    // Try to share data form uninitialized tensor
+    bool caught = false;
+    try {
+      dst_tensor.ShareDataFrom(src_tensor);
+    } catch (EnforceNotMet err) {
+      caught = true;
+      std::string msg = "Can not share data from an uninitialized tensor.";
+      const char* what = err.what();
+      for (size_t i = 0; i < msg.length(); ++i) {
+        ASSERT_EQ(what[i], msg[i]);
+      }
+    }
+    ASSERT_TRUE(caught);
+
+    src_tensor.mutable_data<int>(make_ddim({2, 3, 4}), CPUPlace());
+    dst_tensor.ShareDataFrom(src_tensor);
+    ASSERT_EQ(src_tensor.data<int>(), dst_tensor.data<int>());
+  }
+
+  {
+    Tensor src_tensor;
+    Tensor dst_tensor;
+    src_tensor.mutable_data<int>(make_ddim({2, 3, 4}), GPUPlace());
+    dst_tensor.ShareDataFrom(src_tensor);
+    ASSERT_EQ(src_tensor.data<int>(), dst_tensor.data<int>());
+  }
+}
+
+TEST(Tensor, Slice) {
+  using namespace paddle::framework;
+  using namespace paddle::platform;
+  {
+    Tensor src_tensor;
+    src_tensor.mutable_data<int>(make_ddim({5, 3, 4}), CPUPlace());
+    Tensor slice_tensor = src_tensor.Slice(1, 3);
+    DDim slice_dims = slice_tensor.dims();
+    ASSERT_EQ(arity(slice_dims), 3);
+    EXPECT_EQ(slice_dims[0], 2);
+    EXPECT_EQ(slice_dims[1], 3);
+    EXPECT_EQ(slice_dims[2], 4);
+
+    uintptr_t src_data_address =
+        reinterpret_cast<uintptr_t>(src_tensor.data<int>());
+    uintptr_t src_mutable_data_address = reinterpret_cast<uintptr_t>(
+        src_tensor.mutable_data<int>(src_tensor.dims(), CPUPlace()));
+    uintptr_t slice_data_address =
+        reinterpret_cast<uintptr_t>(slice_tensor.data<int>());
+    uintptr_t slice_mutable_data_address = reinterpret_cast<uintptr_t>(
+        slice_tensor.mutable_data<int>(slice_tensor.dims(), CPUPlace()));
+    EXPECT_EQ(src_data_address, src_mutable_data_address);
+    EXPECT_EQ(slice_data_address, slice_mutable_data_address);
+    EXPECT_EQ(src_data_address + 3 * 4 * 1 * sizeof(int), slice_data_address);
+  }
+
+  {
+    Tensor src_tensor;
+    src_tensor.mutable_data<double>(make_ddim({6, 9}), GPUPlace());
+    Tensor slice_tensor = src_tensor.Slice(2, 6);
+    DDim slice_dims = slice_tensor.dims();
+    ASSERT_EQ(arity(slice_dims), 2);
+    EXPECT_EQ(slice_dims[0], 4);
+    EXPECT_EQ(slice_dims[1], 9);
+
+    uintptr_t src_data_address =
+        reinterpret_cast<uintptr_t>(src_tensor.data<double>());
+    uintptr_t src_mutable_data_address = reinterpret_cast<uintptr_t>(
+        src_tensor.mutable_data<double>(src_tensor.dims(), GPUPlace()));
+    uintptr_t slice_data_address =
+        reinterpret_cast<uintptr_t>(slice_tensor.data<double>());
+    uintptr_t slice_mutable_data_address = reinterpret_cast<uintptr_t>(
+        slice_tensor.mutable_data<double>(slice_tensor.dims(), GPUPlace()));
+    EXPECT_EQ(src_data_address, src_mutable_data_address);
+    EXPECT_EQ(slice_data_address, slice_mutable_data_address);
+    EXPECT_EQ(src_data_address + 9 * 2 * sizeof(double), slice_data_address);
+  }
+}
+
+*/
\ No newline at end of file
diff --git a/paddle/operators/.clang-format b/paddle/operators/.clang-format
deleted file mode 100644
index 29282dc87e2c499988c17d90d47d44cd5cf7f115..0000000000000000000000000000000000000000
--- a/paddle/operators/.clang-format
+++ /dev/null
@@ -1,5 +0,0 @@
----
-Language:        Cpp
-BasedOnStyle:  Google
-Standard:  Cpp11 
-...
diff --git a/paddle/operators/CMakeLists.txt b/paddle/operators/CMakeLists.txt
deleted file mode 100644
index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..0000000000000000000000000000000000000000
diff --git a/paddle/operators/demo_op.h b/paddle/operators/demo_op.h
deleted file mode 100644
index d0b7420b4e25d21f718d5e10d62faeb475931a18..0000000000000000000000000000000000000000
--- a/paddle/operators/demo_op.h
+++ /dev/null
@@ -1,59 +0,0 @@
-#pragma once
-
-#include "paddle/framework/op_registry.h"
-
-using namespace paddle::framework;
-
-namespace paddle {
-namespace operators {
-
-class CosineOp : public OperatorWithKernel {
- public:
-  void Run(const OpRunContext *context) const override {
-    printf("%s\n", DebugString().c_str());
-  }
-};
-
-class CosineOpProtoAndCheckerMaker : public OpProtoAndCheckerMaker {
- public:
-  CosineOpProtoAndCheckerMaker(OpProto *proto, OpAttrChecker *op_checker)
-      : OpProtoAndCheckerMaker(proto, op_checker) {
-    AddInput("input", "input of cosine op");
-    AddOutput("output", "output of cosine op");
-    AddAttr<float>("scale", "scale of cosine op")
-        .SetDefault(1.0)
-        .LargerThan(0.0);
-    AddType("cos");
-    AddComment("This is cos op");
-  }
-};
-
-REGISTER_OP(CosineOp, CosineOpProtoAndCheckerMaker, cos_sim)
-
-class MyTestOp : public OperatorWithKernel {
- public:
-  void Run(const OpRunContext *context) const override {
-    printf("%s\n", DebugString().c_str());
-  }
-};
-
-class MyTestOpProtoAndCheckerMaker : public OpProtoAndCheckerMaker {
- public:
-  MyTestOpProtoAndCheckerMaker(OpProto *proto, OpAttrChecker *op_checker)
-      : OpProtoAndCheckerMaker(proto, op_checker) {
-    AddInput("input", "input of cosine op");
-    AddOutput("output", "output of cosine op");
-    auto my_checker = [](int i) {
-      PADDLE_ENFORCE(i % 2 == 0, "'test_attr' must be even!");
-    };
-    AddAttr<int>("test_attr", "a simple test attribute")
-        .AddCustomChecker(my_checker);
-    AddType("my_test_op");
-    AddComment("This is my_test op");
-  }
-};
-
-REGISTER_OP(MyTestOp, MyTestOpProtoAndCheckerMaker, my_test_op)
-
-}  // namespace operators
-}  // namespace operators
diff --git a/paddle/platform/cuda_device_context.h b/paddle/platform/cuda_device_context.h
index 420159fb2c610f29f60e3b0a11b61e47c13055dc..c38dcd5a6158df92da2f7e19599ab3247df604f3 100644
--- a/paddle/platform/cuda_device_context.h
+++ b/paddle/platform/cuda_device_context.h
@@ -23,15 +23,13 @@ limitations under the License. */
 #include "paddle/platform/place.h"
 #include "unsupported/Eigen/CXX11/Tensor"
 
-using DEVICE_GPU = Eigen::GpuDevice;
-
 namespace paddle {
 namespace platform {
 
 class CUDADeviceContext;
 
 template <>
-DEVICE_GPU DeviceContext::get_eigen_device<DEVICE_GPU>() {
+Eigen::GpuDevice DeviceContext::get_eigen_device<Eigen::GpuDevice>() {
   return static_cast<CUDADeviceContext*>(this)->eigen_handle();
 }
 
@@ -59,6 +57,11 @@ class CUDADeviceContext : public DeviceContext {
     eigen_device_ = new Eigen::GpuDevice(eigen_stream_);
   }
 
+  Place GetPlace() const override {
+    Place retv = GPUPlace();
+    return retv;
+  }
+
   void Wait() {
     paddle::platform::throw_on_error(cudaStreamSynchronize(stream_),
                                      "cudaStreamSynchronize failed");
diff --git a/paddle/platform/device_context.h b/paddle/platform/device_context.h
index 11a05702cd9876c98e730ccaaede2fb04696254e..d2a516999170efd5f5679960670db5b534de9d2f 100644
--- a/paddle/platform/device_context.h
+++ b/paddle/platform/device_context.h
@@ -13,10 +13,10 @@ See the License for the specific language governing permissions and
 limitations under the License. */
 
 #pragma once
+#include "paddle/framework/enforce.h"
+#include "paddle/platform/place.h"
 #include "unsupported/Eigen/CXX11/Tensor"
 
-using DEVICE_CPU = Eigen::DefaultDevice;
-
 namespace paddle {
 namespace platform {
 
@@ -28,10 +28,12 @@ class DeviceContext {
 
   template <typename DeviceType>
   DeviceType get_eigen_device();
+
+  virtual Place GetPlace() const = 0;
 };
 
 template <>
-DEVICE_CPU DeviceContext::get_eigen_device<DEVICE_CPU>() {
+Eigen::DefaultDevice DeviceContext::get_eigen_device<Eigen::DefaultDevice>() {
   return static_cast<CPUDeviceContext*>(this)->eigen_handle();
 }
 
@@ -44,9 +46,13 @@ class CPUDeviceContext : public DeviceContext {
     return *eigen_handle_;
   }
 
+  Place GetPlace() const override {
+    Place retv = CPUPlace();
+    return retv;
+  }
+
  private:
   Eigen::DefaultDevice* eigen_handle_{nullptr};
 };
-
 }  // namespace platform
 }  // namespace paddle