diff --git a/CMakeLists.txt b/CMakeLists.txt
index 611cee46e..e799348fa 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -42,12 +42,13 @@ OPTION(USE_CUDA "Use Cuda libs" OFF)
 OPTION(USE_CUDNN "Use Cudnn libs" ON)
 OPTION(USE_OPENCV "Use opencv" OFF)
 OPTION(USE_LMDB "Use LMDB libs" OFF)
-OPTION(USE_PYTHON "Generate py wrappers" OFF)
+OPTION(USE_PYTHON "Generate py wrappers" ON)
+OPTION(USE_JAVA "Generate java wrappers" OFF)
 OPTION(USE_OPENCL "Use OpenCL" OFF)
 OPTION(ENABLE_DIST "enable distributed training" OFF)
 
 INCLUDE("cmake/Dependencies.cmake")
-INCLUDE("cmake/Utils.cmake")
+#INCLUDE("cmake/Utils.cmake")
 ADD_DEFINITIONS(-DUSE_CMAKE)
 #message(STATUS "${SINGA_INCLUDE_DIR}")
 
@@ -64,6 +65,7 @@ SET(EXECUTABLE_OUTPUT_PATH ${PROJECT_BINARY_DIR}/bin)
 IF (USE_CUDA)
     ADD_SUBDIRECTORY(lib/cnmem)
     LIST(APPEND SINGA_LINKER_LIBS cnmem)
+    SET(global_cuda_objs "")
 ENDIF()
 
 # TODO(wangwei) detect the ev lib
@@ -71,10 +73,20 @@ IF (ENABLE_DIST)
   LIST(APPEND SINGA_LINKER_LIBS ev)
 ENDIF()
 
+INCLUDE_DIRECTORIES("${CMAKE_BINARY_DIR}/include")
 ADD_SUBDIRECTORY(src)
 ADD_SUBDIRECTORY(test)
 ADD_SUBDIRECTORY(examples)
 
+IF (USE_PYTHON)
+  ADD_SUBDIRECTORY(python)
+ENDIF()
+
+IF (USE_JAVA)
+  SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-strict-aliasing ")
+  ADD_SUBDIRECTORY(java)
+ENDIF()
+
 INSTALL(DIRECTORY include/singa DESTINATION ${CMAKE_INSTALL_PREFIX}/include)
 INSTALL(FILES ${CMAKE_BINARY_DIR}/include/singa/singa_config.h DESTINATION
   ${CMAKE_INSTALL_PREFIX}/include/singa)
diff --git a/cmake/Dependencies.cmake b/cmake/Dependencies.cmake
index a4121519c..5f3d6a7e5 100644
--- a/cmake/Dependencies.cmake
+++ b/cmake/Dependencies.cmake
@@ -24,7 +24,7 @@ FIND_PACKAGE( Protobuf REQUIRED )
 INCLUDE_DIRECTORIES(SYSTEM ${PROTOBUF_INCLUDE_DIR})
 MESSAGE(STATUS "proto libs " ${PROTOBUF_LIBRARIES})
 LIST(APPEND SINGA_LINKER_LIBS ${PROTOBUF_LIBRARIES})
-INCLUDE("cmake/Protobuf.cmake")
+#INCLUDE("cmake/Protobuf.cmake")
 
 FIND_PACKAGE(Glog)
 IF(GLOG_FOUND)
@@ -92,3 +92,9 @@ IF(USE_PYTHON)
     FIND_PACKAGE(PythonInterp 2.7 REQUIRED)
     FIND_PACKAGE(SWIG 3.0 REQUIRED)
 ENDIF()
+
+IF(USE_JAVA)
+    FIND_PACKAGE(Java)
+    FIND_PACKAGE(JNI )
+    FIND_PACKAGE(SWIG 3.0 REQUIRED)
+ENDIF()
diff --git a/cmake/Protobuf.cmake b/cmake/Protobuf.cmake
deleted file mode 100644
index 70cf0fea1..000000000
--- a/cmake/Protobuf.cmake
+++ /dev/null
@@ -1,31 +0,0 @@
-# This script is taken from
-# https://github.com/Kitware/CMake/blob/master/Modules/FindProtobuf.cmake
-# and modified to our compilation.
-
-function(PROTOBUF_GENERATE_PYTHON OUTPUT)
-    if(NOT ARGN)
-        message(SEND_ERROR "Error: PROTOBUF_GENERATE_PYTHON() called 
-        without any proto files")
-        return()
-    endif(NOT ARGN)
-
-    set(${OUTPUT})
-    foreach(FIL ${ARGN})
-        get_filename_component(ABS_FIL ${FIL} ABSOLUTE)
-        get_filename_component(FIL_WE ${FIL} NAME_WE)
-        get_filename_component(PATH ${FIL} PATH)
-
-        list(APPEND ${OUTPUT} "${CMAKE_BINARY_DIR}/python/singa/proto/${FIL_WE}_pb2.py")
-
-        add_custom_command(
-            OUTPUT "${CMAKE_BINARY_DIR}/python/singa/proto/${FIL_WE}_pb2.py"
-            COMMAND ${PROTOBUF_PROTOC_EXECUTABLE}
-            ARGS --python_out ${CMAKE_BINARY_DIR}/python/singa/proto
-                 --proto_path ${PATH} ${ABS_FIL}
-            DEPENDS ${ABS_FIL}
-            COMMENT "Running Python protocol buffer compiler on ${FIL}" VERBATIM)
-    endforeach()
-    
-    set_source_files_properties(${${SRCS}} ${${HDRS}} PROPERTIES GENERATED TRUE)
-    set(${OUTPUT} ${${OUTPUT}} PARENT_SCOPE)
-endfunction()
diff --git a/cmake/Utils.cmake b/cmake/Utils.cmake
deleted file mode 100644
index a0373b831..000000000
--- a/cmake/Utils.cmake
+++ /dev/null
@@ -1,70 +0,0 @@
-#
-# Licensed to the Apache Software Foundation (ASF) under one
-# or more contributor license agreements.  See the NOTICE file
-# distributed with this work for additional information
-# regarding copyright ownership.  The ASF licenses this file
-# to you 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.
-# 
-
-
-macro(swig_generate_cxx pylist_variable)
-    if(NOT EXISTS "${CMKAE_BINARY_DIR}/python")
-        execute_process(
-            COMMAND mkdir ${CMAKE_BINARY_DIR}/python
-            COMMAND mkdir ${CMAKE_BINARY_DIR}/python/singa
-            COMMAND mkdir ${CMAKE_BINARY_DIR}/python/singa/proto
-            ERROR_QUIET)
-    endif()
-    execute_process(
-        COMMAND swig -c++ -python -I${CMAKE_SOURCE_DIR}/include 
-        -outdir ${CMAKE_BINARY_DIR}/python/singa
-        ${ARGN})
-
-    set(${pylist_variable} "${CMAKE_SOURCE_DIR}/src/python/swig/singa_wrap.cxx")
-endmacro()
-
-function (create_symlinks)
-    # Do nothing if building in-source
-    if (${CMAKE_CURRENT_BINARY_DIR} STREQUAL ${CMAKE_CURRENT_SOURCE_DIR})
-        return()
-    endif()
-
-    foreach (path_file ${ARGN})
-        get_filename_component(folder ${path_file} PATH)
-
-        # Create REAL folder
-        file(MAKE_DIRECTORY "${CMAKE_BINARY_DIR}/${folder}")
-
-        # Delete symlink if it exists
-        file(REMOVE "${CMAKE_BINARY_DIR}/${path_file}")
-
-        # Get OS dependent path to use in `execute_process`
-        file(TO_NATIVE_PATH "${CMAKE_BINARY_DIR}/${path_file}" link)
-        file(TO_NATIVE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/${path_file}" target)
-
-        if (UNIX)
-            set(command ln -s ${target} ${link})
-        else()
-            set(command cmd.exe /c mklink ${link} ${target})
-        endif()
-
-        execute_process(COMMAND ${command} 
-                        RESULT_VARIABLE result
-                        ERROR_VARIABLE output)
-
-        if (NOT ${result} EQUAL 0)
-            message(FATAL_ERROR "Could not create symbolic link for: ${target} --> ${output}")
-        endif()
-
-    endforeach(path_file)
-endfunction(create_symlinks)
diff --git a/include/singa/core/common.h b/include/singa/core/common.h
index dc552c1d6..9b6e02b7e 100644
--- a/include/singa/core/common.h
+++ b/include/singa/core/common.h
@@ -20,7 +20,7 @@
 #define SINGA_CORE_COMMON_H_
 #include <random>
 #include <chrono>
-#include "./singa/singa_config.h"
+#include "singa/singa_config.h"
 #include <atomic>
 #include <memory>
 #include "singa/utils/logging.h"
@@ -36,7 +36,10 @@
 
 
 #ifdef USE_OPENCL
-#include "singa/utils/opencl_utils.h"
+#define CL_HPP_MINIMUM_OPENCL_VERSION 120
+#define CL_HPP_TARGET_OPENCL_VERSION 120
+#include <CL/cl2.hpp>
+#include <unordered_map>
 #endif  // USE_OPENCL
 
 using std::atomic;
@@ -62,6 +65,9 @@ class Block {
   // Disabled as it is not used currently.
   // Block(void* ptr, size_t size, size_t offset, std::shared_ptr<atomic<int>>
   //  ref) : data_(ptr), size_(size), offset_(offset), ref_count_(ref) {}
+
+	// TODO(wangwei) check if the set is correct and add lock if shared sturcture is allowed
+	void set_data(void* ptr) { data_ = ptr; }
   void* mutable_data() {
     initialized_ = true;
     return static_cast<char*>(data_) + offset_;
@@ -107,8 +113,9 @@ typedef struct _Context {
 #endif // USE_CUDA
 
 #ifdef USE_OPENCL
-  // This stores the context ID of the OpenCL context controlled by ViennaCL.
-  long vcl_ctx_id;
+  std::shared_ptr<std::unordered_map<std::string, cl::Kernel>> kernels;
+  cl::CommandQueue ocl_cmdq;
+  cl::Context ocl_ctx;
 #endif
 
 } Context;
diff --git a/include/singa/core/memory.h b/include/singa/core/memory.h
index f664f95ce..d0a8afa80 100644
--- a/include/singa/core/memory.h
+++ b/include/singa/core/memory.h
@@ -23,6 +23,7 @@
 #include <atomic>
 #include "singa/proto/core.pb.h"
 #include "singa/singa_config.h"
+#include "singa/core/common.h"
 
 #ifdef USE_CUDA
 #include "cnmem.h"
@@ -50,6 +51,37 @@ class DeviceMemPool {
 //  size_t init_size_ = 0, max_size_ = 0;
 };
 
+class CppMemPool {
+	public:
+		CppMemPool();
+		
+		Block* Malloc(const size_t size);
+		void Free(Block* ptr);
+
+		// get the free and total size of the memory pool (in terms of bytes)
+  	std::pair<size_t, size_t> GetMemUsage(){return std::make_pair(freeSize,memPoolSize);};
+
+  	~CppMemPool();
+
+	private:
+		// each structure define a memory uint in the memory pool
+		// the structure is a static double linked list
+		struct _Uint {
+			struct _Uint *pPrev, *pNext;
+			Block* pBlk;
+		};
+
+		// total size held by the memory pool (in terms of bytes)
+		size_t memPoolSize;
+		// total free size by the memory pool (in terms of bytes)
+		size_t freeSize;
+
+		// each pointer in this array keeps a head of the allocated memory uints of different size (power of 2)
+		struct _Uint **ppAllocUints;
+		// each pointer in this array keeps a head of the allocated memory uints of different size (power of 2)
+		struct _Uint **ppFreeUints;
+};
+
 #ifdef USE_CUDA
 class CnMemPool : public DeviceMemPool {
  public:
diff --git a/java/CMakeLists.txt b/java/CMakeLists.txt
new file mode 100644
index 000000000..ef384611f
--- /dev/null
+++ b/java/CMakeLists.txt
@@ -0,0 +1,138 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you 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.
+#
+
+# This following function is taken from
+# https://github.com/Kitware/CMake/blob/master/Modules/FindProtobuf.cmake
+# and modified to our compilation.
+function(PROTOBUF_GENERATE_JAVA OUTPUT)
+    if(NOT ARGN)
+        message(SEND_ERROR "Error: PROTOBUF_GENERATE_JAVA() called 
+        without any proto files")
+        return()
+    endif(NOT ARGN)
+
+    set(${OUTPUT})
+    foreach(FIL ${ARGN})
+        get_filename_component(ABS_FIL ${FIL} ABSOLUTE)
+        get_filename_component(FIL_WE ${FIL} NAME_WE)
+        get_filename_component(PATH ${FIL} PATH)
+
+        list(APPEND ${OUTPUT} "${CMAKE_BINARY_DIR}/java/singa/proto/${FIL_WE}.java")
+
+        add_custom_command(
+            OUTPUT "${CMAKE_BINARY_DIR}/java/singa/proto/${FIL_WE}.java"
+            COMMAND ${PROTOBUF_PROTOC_EXECUTABLE}
+            ARGS --java_out ${CMAKE_BINARY_DIR}/java
+                 --proto_path ${PATH} ${ABS_FIL}
+            DEPENDS ${ABS_FIL}
+            COMMENT "Running java protocol buffer compiler on ${FIL}" VERBATIM)
+    endforeach()
+    
+    set_source_files_properties(${${SRCS}} ${${HDRS}} PROPERTIES GENERATED TRUE)
+    set(${OUTPUT} ${${OUTPUT}} PARENT_SCOPE)
+endfunction()
+
+function (create_symlinks)
+    # Do nothing if building in-source
+    if (${CMAKE_CURRENT_BINARY_DIR} STREQUAL ${CMAKE_CURRENT_SOURCE_DIR})
+        return()
+    endif()
+
+    foreach (path_file ${ARGN})
+        get_filename_component(folder ${path_file} PATH)
+
+        # Delete symlink if it exists
+        file(REMOVE "${CMAKE_CURRENT_BINARY_DIR}/${path_file}")
+
+        # Get OS dependent path to use in `execute_process`
+        file(TO_NATIVE_PATH "${CMAKE_CURRENT_BINARY_DIR}/${path_file}" link)
+        file(TO_NATIVE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/${path_file}" target)
+
+        if (UNIX)
+            set(command ln -s ${target} ${link})
+        else()
+            set(command cmd.exe /c mklink ${link} ${target})
+        endif()
+
+        execute_process(COMMAND ${command} 
+                        RESULT_VARIABLE result
+                        ERROR_VARIABLE output)
+
+        if (NOT ${result} EQUAL 0)
+            message(FATAL_ERROR "Could not create symbolic link for: ${target} --> ${output}")
+        endif()
+
+    endforeach(path_file)
+endfunction(create_symlinks)
+
+
+# generate protobuf sources
+FILE(GLOB proto_files ${CMAKE_SOURCE_DIR}/src/proto/*.proto)
+PROTOBUF_GENERATE_JAVA(proto_javas ${proto_files})
+MESSAGE(STATUS "proto javas: ${proto_javas}")
+
+# generate cxx and wrap.py
+if(NOT EXISTS "${CMKAE_BINARY_DIR}/java")
+    execute_process(
+        COMMAND mkdir ${CMAKE_BINARY_DIR}/java
+        COMMAND mkdir ${CMAKE_BINARY_DIR}/java/singa
+        COMMAND mkdir ${CMAKE_BINARY_DIR}/java/singa/proto
+        ERROR_QUIET)
+endif()
+execute_process(
+    COMMAND mkdir ${CMAKE_BINARY_DIR}/src/api
+    COMMAND swig -c++ -java -I${CMAKE_SOURCE_DIR}/include 
+    -I${JAVA_INCLUDE_PATH} -I${JAVA_INCLUDE_PATH2}
+    -outdir ${CMAKE_BINARY_DIR}/java/singa
+    -package singa 
+    -o ${CMAKE_BINARY_DIR}/src/api/singa_java_wrap.cxx
+    ${CMAKE_SOURCE_DIR}/src/api/singa.i )
+
+#MESSAGE(STATUS "java include: ${JAVA_INCLUDE_DIRS} ${JNI_INCLUDE_DIRS} ${JAVA_INCLUDE_PATH} ${JAVA_INCLUDE_PATH2}")
+set(java_srcs "${CMAKE_BINARY_DIR}/src/api/singa_java_wrap.cxx")
+
+#Create symlinks for all java source files  Do not omit !!!RELATIVE!!!
+file(GLOB_RECURSE java_source_files RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} *.java)
+create_symlinks(${java_source_files})
+
+IF(USE_CUDA)
+# remain this custom command to avoid cuda objs can't find 
+ADD_CUSTOM_COMMAND(
+    OUTPUT ${global_cuda_objs}
+    COMMAND ${CMAKE_COMMAND} -E make_directory "${CMAKE_BINARY_DIR}/"
+    )
+ENDIF(USE_CUDA)
+
+
+ADD_LIBRARY(singa_wrap SHARED $<TARGET_OBJECTS:singa_objects>  ${java_srcs} ${proto_javas} ${global_cuda_objs})
+TARGET_LINK_LIBRARIES(singa_wrap ${SINGA_LINKER_LIBS} ${JNI_LIBRARIES})
+TARGET_INCLUDE_DIRECTORIES(singa_wrap PRIVATE ${JAVA_INCLUDE_PATH} ${JAVA_INCLUDE_PATH2})
+
+SET_TARGET_PROPERTIES(singa_wrap
+    PROPERTIES LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/java/singa
+)
+
+IF(APPLE)
+ADD_CUSTOM_TARGET(
+    change_suffix ALL 
+    COMMAND ${CMAKE_COMMAND} -E rename "${CMAKE_BINARY_DIR}/java/singa/libsinga_wrap.dylib" "${CMAKE_BINARY_DIR}/java/singa/libsinga_wrap.so"
+    COMMENT "change .dylib to .so in mac system"
+)
+ADD_DEPENDENCIES(change_suffix _singa_wrap)
+ENDIF(APPLE)
+
diff --git a/python/CMakeLists.txt b/python/CMakeLists.txt
new file mode 100644
index 000000000..8bf831961
--- /dev/null
+++ b/python/CMakeLists.txt
@@ -0,0 +1,147 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# This following function is taken from
+# https://github.com/Kitware/CMake/blob/master/Modules/FindProtobuf.cmake
+# and modified to our compilation.
+function(PROTOBUF_GENERATE_PYTHON OUTPUT)
+    if(NOT ARGN)
+        message(SEND_ERROR "Error: PROTOBUF_GENERATE_PYTHON() called 
+        without any proto files")
+        return()
+    endif(NOT ARGN)
+
+    set(${OUTPUT})
+    foreach(FIL ${ARGN})
+        get_filename_component(ABS_FIL ${FIL} ABSOLUTE)
+        get_filename_component(FIL_WE ${FIL} NAME_WE)
+        get_filename_component(PATH ${FIL} PATH)
+
+        list(APPEND ${OUTPUT} "${CMAKE_BINARY_DIR}/python/singa/proto/${FIL_WE}_pb2.py")
+
+        add_custom_command(
+            OUTPUT "${CMAKE_BINARY_DIR}/python/singa/proto/${FIL_WE}_pb2.py"
+            COMMAND ${PROTOBUF_PROTOC_EXECUTABLE}
+            ARGS --python_out ${CMAKE_BINARY_DIR}/python/singa/proto
+                 --proto_path ${PATH} ${ABS_FIL}
+            DEPENDS ${ABS_FIL}
+            COMMENT "Running Python protocol buffer compiler on ${FIL}" VERBATIM)
+    endforeach()
+    
+    set_source_files_properties(${${SRCS}} ${${HDRS}} PROPERTIES GENERATED TRUE)
+    set(${OUTPUT} ${${OUTPUT}} PARENT_SCOPE)
+endfunction()
+
+function (create_symlinks)
+    # Do nothing if building in-source
+    if (${CMAKE_CURRENT_BINARY_DIR} STREQUAL ${CMAKE_CURRENT_SOURCE_DIR})
+        return()
+    endif()
+
+    foreach (path_file ${ARGN})
+        get_filename_component(folder ${path_file} PATH)
+
+        # Create REAL folder
+        #file(MAKE_DIRECTORY "${CMAKE_BINARY_DIR}/${folder}")
+
+        # Delete symlink if it exists
+        file(REMOVE "${CMAKE_CURRENT_BINARY_DIR}/${path_file}")
+
+        # Get OS dependent path to use in `execute_process`
+        file(TO_NATIVE_PATH "${CMAKE_CURRENT_BINARY_DIR}/${path_file}" link)
+        file(TO_NATIVE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/${path_file}" target)
+
+        if (UNIX)
+            set(command ln -s ${target} ${link})
+        else()
+            set(command cmd.exe /c mklink ${link} ${target})
+        endif()
+
+        execute_process(COMMAND ${command} 
+                        RESULT_VARIABLE result
+                        ERROR_VARIABLE output)
+
+        if (NOT ${result} EQUAL 0)
+            message(FATAL_ERROR "Could not create symbolic link for: ${target} --> ${output}")
+        endif()
+
+    endforeach(path_file)
+endfunction(create_symlinks)
+
+
+# generate protobuf sources
+FILE(GLOB proto_files ${CMAKE_SOURCE_DIR}/src/proto/*.proto)
+PROTOBUF_GENERATE_PYTHON(proto_pys ${proto_files})
+#MESSAGE(STATUS "proto pys: ${proto_pys}")
+
+# generate cxx and wrap.py
+if(NOT EXISTS "${CMKAE_BINARY_DIR}/python")
+    execute_process(
+        COMMAND mkdir ${CMAKE_BINARY_DIR}/python
+        COMMAND mkdir ${CMAKE_BINARY_DIR}/python/singa
+        COMMAND mkdir ${CMAKE_BINARY_DIR}/python/singa/proto
+        ERROR_QUIET)
+endif()
+execute_process(
+    COMMAND mkdir ${CMAKE_BINARY_DIR}/src/api
+    COMMAND swig -c++ -python -I${CMAKE_SOURCE_DIR}/include 
+    -outdir ${CMAKE_BINARY_DIR}/python/singa
+    -o ${CMAKE_BINARY_DIR}/src/api/singa_wrap.cxx
+    ${CMAKE_SOURCE_DIR}/src/api/singa.i )
+
+set(python_srcs "${CMAKE_BINARY_DIR}/src/api/singa_wrap.cxx")
+
+#Create symlinks for all python source files  Do not omit !!!RELATIVE!!!
+file(GLOB_RECURSE python_source_files RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} *.py)
+create_symlinks(${python_source_files})
+
+
+IF(USE_CUDA)
+# remain this custom command to avoid cuda objs can't find 
+ADD_CUSTOM_COMMAND(
+    OUTPUT ${global_cuda_objs}
+    COMMAND ${CMAKE_COMMAND} -E make_directory "${CMAKE_BINARY_DIR}/"
+    )
+ENDIF(USE_CUDA)
+
+ADD_LIBRARY(_singa_wrap SHARED $<TARGET_OBJECTS:singa_objects>  ${python_srcs} ${proto_pys} ${global_cuda_objs})
+TARGET_LINK_LIBRARIES(_singa_wrap ${SINGA_LINKER_LIBS} ${PYTHON_LIBRARIES})
+TARGET_INCLUDE_DIRECTORIES(_singa_wrap PRIVATE ${PYTHON_INCLUDE_DIRS})
+SET_TARGET_PROPERTIES(_singa_wrap
+PROPERTIES PREFIX ""
+LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/python/singa
+)
+
+#SETUP
+SET(SETUP_PY_IN "setup.py.in")
+SET(SETUP_PY    "${CMAKE_BINARY_DIR}/python/setup.py")
+CONFIGURE_FILE(${SETUP_PY_IN} ${SETUP_PY})
+
+#create python/singa/proto/__init__.py
+FILE(WRITE ${CMAKE_BINARY_DIR}/python/singa/proto/__init__.py "")
+#MESSAGE(STATUS "apple: ${APPLE}")
+IF(APPLE)
+ADD_CUSTOM_TARGET(
+    change_suffix ALL 
+    COMMAND ${CMAKE_COMMAND} -E rename "${CMAKE_BINARY_DIR}/python/singa/_singa_wrap.dylib" "${CMAKE_BINARY_DIR}/python/singa/_singa_wrap.so"
+    COMMENT "change .dylib to .so in mac system"
+)
+ADD_DEPENDENCIES(change_suffix _singa_wrap)
+ENDIF(APPLE)
+
+
diff --git a/src/python/setup.py.in b/python/setup.py.in
similarity index 100%
rename from src/python/setup.py.in
rename to python/setup.py.in
diff --git a/src/python/singa/__init__.py b/python/singa/__init__.py
similarity index 100%
rename from src/python/singa/__init__.py
rename to python/singa/__init__.py
diff --git a/src/python/singa/command.py b/python/singa/command.py
similarity index 100%
rename from src/python/singa/command.py
rename to python/singa/command.py
diff --git a/src/python/singa/device.py b/python/singa/device.py
similarity index 100%
rename from src/python/singa/device.py
rename to python/singa/device.py
diff --git a/src/python/singa/initializer.py b/python/singa/initializer.py
similarity index 100%
rename from src/python/singa/initializer.py
rename to python/singa/initializer.py
diff --git a/src/python/singa/layer.py b/python/singa/layer.py
similarity index 100%
rename from src/python/singa/layer.py
rename to python/singa/layer.py
diff --git a/src/python/singa/loss.py b/python/singa/loss.py
similarity index 95%
rename from src/python/singa/loss.py
rename to python/singa/loss.py
index c88290bc4..526e4d09f 100644
--- a/src/python/singa/loss.py
+++ b/python/singa/loss.py
@@ -95,6 +95,7 @@ class SoftmaxCrossEntropy(Loss):
     '''
 
     def __init__(self):
+        super(SoftmaxCrossEntropy, self).__init__()
         self.swig_loss = singa.SoftmaxCrossEntropy()
 
 
@@ -105,7 +106,7 @@ class SquaredError(Loss):
     It is implemented using Python Tensor operations.
     '''
     def __init__(self):
-        super(Loss, SquaredError).__init__()
+        super(SquareLoss, self).__init__()
         self.err = None
 
     def forward(self, flag, x, y):
@@ -122,7 +123,7 @@ def forward(self, flag, x, y):
             a Tensor with one error value per sample
         '''
         self.err = x - y
-        return 0.5 * tensor.squared(self.err)
+        return tensor.square(self.err) * 0.5
 
     def backward(self):
         '''Compute the gradient of x w.r.t the error.
@@ -138,4 +139,4 @@ def evaluate(self, flag, x, y):
         Returns:
             a float value as the averaged error
         '''
-        return tensor.sum(0.5 * tensor.squared(x - y)) / x.size()
+        return tensor.sum(tensor.square(x - y) * 0.5) / x.size()
diff --git a/src/python/singa/metric.py b/python/singa/metric.py
similarity index 100%
rename from src/python/singa/metric.py
rename to python/singa/metric.py
diff --git a/src/python/singa/model.py b/python/singa/model.py
similarity index 100%
rename from src/python/singa/model.py
rename to python/singa/model.py
diff --git a/src/python/singa/net.py b/python/singa/net.py
similarity index 100%
rename from src/python/singa/net.py
rename to python/singa/net.py
diff --git a/src/python/singa/optimizer.py b/python/singa/optimizer.py
similarity index 100%
rename from src/python/singa/optimizer.py
rename to python/singa/optimizer.py
diff --git a/src/python/singa/tensor.py b/python/singa/tensor.py
similarity index 97%
rename from src/python/singa/tensor.py
rename to python/singa/tensor.py
index f6bca432b..102448335 100644
--- a/src/python/singa/tensor.py
+++ b/python/singa/tensor.py
@@ -372,6 +372,7 @@ def __idiv__(self, x):
 
     '''
     python operators (+, -, *, /, <, <=, >, >=) for singa binary operators
+    https://docs.python.org/2/library/operator.html#mapping-operators-to-functions
     '''
 
     def __add__(self, rhs):
@@ -441,6 +442,29 @@ def __ge__(self, rhs):
             return _call_singa_func(singa.GE_Tf, self.singa_tensor, rhs)
 
 
+    def __radd__(self, lhs):
+        lhs = float(lhs)
+        return _call_singa_func(singa.Add_Tf, self.singa_tensor, lhs)
+
+    def __rsub__(self, lhs):
+        lhs = float(lhs)
+        ret = _call_singa_func(singa.Sub_Tf, self.singa_tensor, lhs)
+        ret *= -1
+        return ret
+
+    def __rmul__(self, lhs):
+        lhs = float(lhs)
+        return _call_singa_func(singa.EltwiseMul_Tf, self.singa_tensor, lhs)
+
+    def __rdiv__(self, lhs):
+        lhs = float(lhs)
+        one = Tensor(self.shape, self.device, self.dtype)
+        one.set_value(1)
+        one *= lhs
+        return _call_singa_func(singa.Div_TT, one.singa_tensor,\
+                self.singa_tensor)
+
+
 ''' python functions for global functions in Tensor.h
 '''
 
diff --git a/src/python/singa/utils.py b/python/singa/utils.py
similarity index 100%
rename from src/python/singa/utils.py
rename to python/singa/utils.py
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index b4a88f592..5f7020494 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -20,10 +20,9 @@
 
 FILE(GLOB proto_files proto/*.proto)
 protobuf_generate_cpp(proto_srcs proto_hdrs ${proto_files})
-INCLUDE_DIRECTORIES("${CMAKE_BINARY_DIR}/include")
+#MESSAGE(STATUS "proto_srcs: ${proto_srcs}")
 
 LIST(APPEND singa_sources ${proto_hdrs} ${proto_srcs})
-SET(PREVIOUS_LINKER_LIBS ${SINGA_LINKER_LIBS})
 
 AUX_SOURCE_DIRECTORY(utils utils_source)
 LIST(APPEND singa_sources ${utils_source})
@@ -32,6 +31,8 @@ AUX_SOURCE_DIRECTORY(core/device core_source)
 AUX_SOURCE_DIRECTORY(core/memory core_source)
 AUX_SOURCE_DIRECTORY(core/scheduler core_source)
 AUX_SOURCE_DIRECTORY(core/tensor core_source)
+LIST(APPEND singa_sources ${core_source})
+
 IF (USE_CUDA)
     FILE(GLOB_RECURSE cuda_source core "*.cu")
     SET(FLAGS_BACKUP ${CMAKE_CXX_FLAGS})
@@ -45,7 +46,8 @@ IF (USE_CUDA)
     include_directories("${CMAKE_CURRENT_SOURCE_DIR}/core/tensor")
     SET(CMAKE_CXX_FLAGS ${FLAGS_BACKUP})
 ENDIF (USE_CUDA)
-LIST(APPEND singa_sources ${core_source} ${cuda_objs})
+
+SET(global_cuda_objs ${cuda_objs} PARENT_SCOPE)
 
 AUX_SOURCE_DIRECTORY(model model_source)
 AUX_SOURCE_DIRECTORY(model/layer model_source)
@@ -58,72 +60,31 @@ LIST(APPEND singa_sources ${model_source})
 AUX_SOURCE_DIRECTORY(io io_source)
 AUX_SOURCE_DIRECTORY(io/network io_source)
 LIST(APPEND singa_sources ${io_source})
-ADD_LIBRARY(singa SHARED ${singa_sources})
+
 ADD_CUSTOM_TARGET(
-  copy_protobuf
+  copy_protobuf ALL
   COMMAND ${CMAKE_COMMAND} -E make_directory "${CMAKE_BINARY_DIR}/include/singa/proto"
   DEPENDS ${proto_hdrs}
   COMMENT "Copying Protobuf headers"
   )
 FOREACH(fil ${proto_hdrs})
+  GET_FILENAME_COMPONENT(filename ${fil} NAME)
   ADD_CUSTOM_COMMAND(
-    TARGET copy_protobuf PRE_BUILD
-    COMMAND ${CMAKE_COMMAND} -E copy ${fil} "${CMAKE_BINARY_DIR}/include/singa/proto"
+    TARGET copy_protobuf POST_BUILD
+    COMMAND ${CMAKE_COMMAND} -E copy_if_different ${fil}
+    "${CMAKE_BINARY_DIR}/include/singa/proto/${filename}"
+    DEPENDS ${proto_files} 
  )
 ENDFOREACH()
-ADD_DEPENDENCIES(singa copy_protobuf)
-TARGET_LINK_LIBRARIES(singa ${SINGA_LINKER_LIBS})
-#MESSAGE(STATUS "HEADERS: ${proto_hdrs}")
-
-IF(USE_PYTHON)
-
-    protobuf_generate_python(proto_pys ${proto_files})
-    #MESSAGE(STATUS "proto pys: ${proto_pys}")
-    FILE(REMOVE "${CMAKE_CURRENT_SOURCE_DIR}/python/swig/config.i")
-    CONFIGURE_FILE("${CMAKE_CURRENT_SOURCE_DIR}/python/swig/config.i.in" "${CMAKE_CURRENT_SOURCE_DIR}/python/swig/config.i")
-
-    FILE(GLOB python_files python/swig/singa.i)
-    # delete old .cxx file
-    FILE(REMOVE "${CMAKE_CURRENT_SOURCE_DIR}/python/swig/singa_wrap.cxx")
 
-    # generate cxx and wrap.py
-    swig_generate_cxx(python_srcs ${python_files})
+ADD_LIBRARY(singa_objects OBJECT ${singa_sources})
+#ADD_DEPENDENCIES(singa_objects copy_protobuf)
 
-    #FILE(COPY python/ DESTINATION ${CMAKE_BINARY_DIR}/python/singa FILES_MATCHING PATTERN "swig" EXCLUDE PATTERN "*.py")
-    #Create symlinks for all python source files  Do not omit !!!RELATIVE!!!
-    file(GLOB_RECURSE python_source_files RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} *.py)
-
-    create_symlinks(${python_source_files})
-
-    ADD_LIBRARY(_singa_wrap SHARED ${python_srcs} ${singa_sources} ${cuda_objs} ${proto_pys})
-    SET(WRAPPER_LINKER_LIBS "${PREVIOUS_LINKER_LIBS}")
-    TARGET_LINK_LIBRARIES(_singa_wrap ${WRAPPER_LINKER_LIBS} ${PYTHON_LIBRARIES})
-    TARGET_INCLUDE_DIRECTORIES(_singa_wrap PRIVATE ${PYTHON_INCLUDE_DIRS})
-    ADD_DEPENDENCIES(_singa_wrap singa )
-    #message(STATUS "PREVIOUS_LINKER_LIBS ${PREVIOUS_LINKER_LIBS}")
-
-    SET_TARGET_PROPERTIES(_singa_wrap
-        PROPERTIES PREFIX ""
-        LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/python/singa
-        )
-
-    #SETUP
-    SET(SETUP_PY_IN "python/setup.py.in")
-    SET(SETUP_PY    "${CMAKE_BINARY_DIR}/python/setup.py")
-    CONFIGURE_FILE(${SETUP_PY_IN} ${SETUP_PY})
-
-    #create python/singa/proto/__init__.py
-    FILE(WRITE ${CMAKE_BINARY_DIR}/python/singa/proto/__init__.py "")
-    #MESSAGE(STATUS "apple: ${APPLE}")
-    IF(APPLE)
-        ADD_CUSTOM_TARGET(
-            change_suffix ALL 
-            COMMAND ${CMAKE_COMMAND} -E rename "${CMAKE_BINARY_DIR}/python/singa/_singa_wrap.dylib" "${CMAKE_BINARY_DIR}/python/singa/_singa_wrap.so"
-            COMMENT "change .dylib to .so in mac system"
-        )
-        ADD_DEPENDENCIES(change_suffix _singa_wrap)
-    ENDIF(APPLE)
+ADD_LIBRARY(singa SHARED $<TARGET_OBJECTS:singa_objects> ${cuda_objs})
+TARGET_LINK_LIBRARIES(singa ${SINGA_LINKER_LIBS})
 
-ENDIF(USE_PYTHON)
+#pass configure infor to swig 
+FILE(REMOVE "${CMAKE_CURRENT_SOURCE_DIR}/api/config.i")
+CONFIGURE_FILE("${CMAKE_CURRENT_SOURCE_DIR}/api/config.i.in" "${CMAKE_CURRENT_SOURCE_DIR}/api/config.i")
 
 
diff --git a/src/api/.gitignore b/src/api/.gitignore
new file mode 100644
index 000000000..adb5d03a3
--- /dev/null
+++ b/src/api/.gitignore
@@ -0,0 +1 @@
+config.i
diff --git a/src/python/swig/config.i.in b/src/api/config.i.in
similarity index 74%
rename from src/python/swig/config.i.in
rename to src/api/config.i.in
index 5743ba30f..7da916ccb 100644
--- a/src/python/swig/config.i.in
+++ b/src/api/config.i.in
@@ -1,4 +1,6 @@
 // Pass in cmake configurations to swig
 #cmakedefine01 USE_CUDA
 #cmakedefine01 USE_CUDNN
+#cmakedefine01 USE_PYTHON
+#cmakedefine01 USE_JAVA
 #cmakedefine CUDNN_VERSION_SWIG ${CUDNN_VERSION_SWIG}
diff --git a/src/python/swig/core_device.i b/src/api/core_device.i
similarity index 100%
rename from src/python/swig/core_device.i
rename to src/api/core_device.i
diff --git a/src/python/swig/core_tensor.i b/src/api/core_tensor.i
similarity index 99%
rename from src/python/swig/core_tensor.i
rename to src/api/core_tensor.i
index 60f8b45a5..d85e7f081 100644
--- a/src/python/swig/core_tensor.i
+++ b/src/api/core_tensor.i
@@ -44,10 +44,13 @@ using singa::DataType;
 %}
 %shared_ptr(singa::Device)
 
+#if USE_PYTHON
 %include "numpy.i"
 %init %{
   import_array();
 %}
+#endif //USE_PYTHON
+
 %apply (float *IN_ARRAY1, int DIM1) {
        (const float *src, const size_t num)
 }
diff --git a/src/python/swig/model_layer.i b/src/api/model_layer.i
similarity index 100%
rename from src/python/swig/model_layer.i
rename to src/api/model_layer.i
diff --git a/src/python/swig/model_loss.i b/src/api/model_loss.i
similarity index 100%
rename from src/python/swig/model_loss.i
rename to src/api/model_loss.i
diff --git a/src/python/swig/model_metric.i b/src/api/model_metric.i
similarity index 100%
rename from src/python/swig/model_metric.i
rename to src/api/model_metric.i
diff --git a/src/python/swig/model_optimizer.i b/src/api/model_optimizer.i
similarity index 100%
rename from src/python/swig/model_optimizer.i
rename to src/api/model_optimizer.i
diff --git a/src/python/swig/numpy.i b/src/api/numpy.i
similarity index 100%
rename from src/python/swig/numpy.i
rename to src/api/numpy.i
diff --git a/src/python/swig/singa.i b/src/api/singa.i
similarity index 100%
rename from src/python/swig/singa.i
rename to src/api/singa.i
diff --git a/src/core/memory/memory.cc b/src/core/memory/memory.cc
index cb33a48cd..1abbbb326 100644
--- a/src/core/memory/memory.cc
+++ b/src/core/memory/memory.cc
@@ -20,9 +20,123 @@
 #include "singa/utils/logging.h"
 #include "singa/proto/core.pb.h"
 #include <iostream>
+/*
+int get_pos(size_t size) {
+	int result = 0;
+	while(size > 1) {
+		result++;
+		size = size/2;
+	}
+	return result;
+}
+*/
+namespace singa {
+
+CppMemPool::CppMemPool()	{
+	memPoolSize = 0;
+	freeSize = 0;
+	ppAllocUints = (struct _Uint**)malloc(64*sizeof(struct _Uint*));
+	ppFreeUints = (struct _Uint**)malloc(64*sizeof(struct _Uint*));
+	for(int i = 0; i < 64; i++) {
+		ppAllocUints[i] = NULL;
+		ppFreeUints[i] = NULL;
+	}
+}
+
+
+Block* CppMemPool::Malloc(const size_t size) {	
+	CHECK(size > 0);
+	Block *pAllocBlk = NULL;
+	int pos = 63 - __builtin_clzll(size);
+	
+	struct _Uint*& pAllocUint = ppAllocUints[pos];
+	struct _Uint*& pFreeUint = ppFreeUints[pos];
+	struct _Uint* pCurUint = NULL;
+	size_t memSize = pow(2,pos);
+	size_t blkSize = (size % memSize == 0) ? memSize : memSize*2;
+	blkSize += sizeof(struct _Uint);
+	
+	if(pFreeUint == NULL) { // if no available free blocks
+		memPoolSize += blkSize;
+		pCurUint = (struct _Uint*)malloc(blkSize);
+		pCurUint->pPrev = NULL;
+		pCurUint->pNext = pAllocUint; 
+		if(pAllocUint != NULL) {
+			pAllocUint->pPrev = pCurUint;
+		}
+		pAllocUint = pCurUint;
+		pAllocBlk = new Block((char*)(pCurUint) + sizeof(struct _Uint), size);
+		pCurUint->pBlk = pAllocBlk;
+	} else {
+		freeSize -= blkSize;
+		pCurUint = pFreeUint;
+		pFreeUint = pCurUint->pNext;
+		if(pFreeUint != NULL) {
+			pFreeUint->pPrev = NULL;
+		}
+		
+		pCurUint->pNext = pAllocUint;
+		if(pAllocUint != NULL) {
+			pAllocUint->pPrev = pCurUint;
+		}
+		pAllocUint = pCurUint;
+		pAllocBlk = pCurUint->pBlk;
+	}
+	return pAllocBlk;
+}
+
+void CppMemPool::Free(Block* ptr) {
+	void* pData = ptr->mutable_data();	
+	struct _Uint *pCurUint = (struct _Uint*)((char*)pData-sizeof(struct _Uint));
+	int pos = 63 - __builtin_clzll(ptr->size());
+	struct _Uint*& pAllocUint = ppAllocUints[pos];
+	struct _Uint*& pFreeUint = ppFreeUints[pos];
+	size_t memSize = pow(2,pos); 
+	size_t blkSize = (ptr->size() % memSize == 0) ? memSize : memSize*2;
+	blkSize += sizeof(struct _Uint);
+	freeSize += blkSize;
+
+	if(pCurUint == pAllocUint) {
+		pAllocUint = pCurUint->pNext;
+		if(pAllocUint != NULL) {
+			pAllocUint->pPrev = NULL;
+		}		
+	} else {
+		struct _Uint *pCurPrevUint = pCurUint->pPrev;
+		pCurUint->pPrev = NULL;
+		pCurPrevUint->pNext = pCurUint->pNext;
+		if(pCurUint->pNext != NULL) {
+			pCurUint->pNext->pPrev = pCurPrevUint;
+		}
+	}
+
+	pCurUint->pNext = pFreeUint;
+	if(pFreeUint != NULL) {
+		pFreeUint->pPrev = pCurUint;
+	}		
+	pFreeUint = pCurUint;
+}
+
+
+CppMemPool::~CppMemPool() {
+	// traverse all lists to delete the memory
+	for(int pos = 0; pos < 64; pos++) {
+		for(int i = 0; i < 2; i++) {
+			struct _Uint *pCurUint = i == 0 ? ppAllocUints[pos] : ppFreeUints[pos];
+			while(pCurUint != NULL) {
+				struct _Uint *pNextUint = pCurUint->pNext;
+				free(pCurUint->pBlk);
+				free(pCurUint);
+				pCurUint = pNextUint;
+			}
+		}
+	}
+	free(ppAllocUints);
+	free(ppFreeUints);
+}
+
 
 #ifdef USE_CUDA
-namespace singa {
 std::atomic<int> CnMemPool::pool_count(0);
 std::pair<size_t, size_t> CnMemPool::GetMemUsage() {
   size_t free, total;
@@ -107,5 +221,5 @@ void CudaMemPool::Free(void *ptr) {
   cudaError_t status = cudaFree(ptr);
   CHECK_EQ(status, cudaError_t::cudaSuccess);
 }
-}
 #endif
+}
diff --git a/src/proto/core.proto b/src/proto/core.proto
index c88bee9f4..dc5ed3456 100644
--- a/src/proto/core.proto
+++ b/src/proto/core.proto
@@ -18,6 +18,8 @@
 
 package singa;
 
+option java_package = "singa.proto";
+
 // TODO(wangwei) check protobuf version to include the syntax
 //syntax = "proto2";
 
diff --git a/src/proto/io.proto b/src/proto/io.proto
index f349f742e..ab5698389 100644
--- a/src/proto/io.proto
+++ b/src/proto/io.proto
@@ -18,6 +18,7 @@
 
 package singa;
 
+option java_package = "singa.proto";
 
 message EncoderConf {
   optional string type = 1 [default = "jpg2proto"];
diff --git a/src/proto/model.proto b/src/proto/model.proto
index 3df68e2e8..6be5e0a4b 100644
--- a/src/proto/model.proto
+++ b/src/proto/model.proto
@@ -18,6 +18,7 @@
 
 package singa;
 
+option java_package = "singa.proto";
 /// \file layer.proto is adapted from [Caffe](https://github.com/BVLC/caffe/)'s
 /// proto file with commit id c419f8517b1e1b3d7a07fe212fc6c90a70b519ea. We
 /// use caffe's protocol for configuring layer hyper-parameters for easy
diff --git a/test/java/Test.java b/test/java/Test.java
new file mode 100644
index 000000000..f9e541198
--- /dev/null
+++ b/test/java/Test.java
@@ -0,0 +1,12 @@
+import singa.*;
+
+public class Test {
+  static {
+    System.loadLibrary("singa_wrap");
+  }
+
+  public static void main(String argv[]) {
+    Tensor t = new Tensor();
+    System.out.println(t);
+  }
+}
diff --git a/test/python/test_tensor.py b/test/python/test_tensor.py
index 2374adce1..a1f220bc4 100644
--- a/test/python/test_tensor.py
+++ b/test/python/test_tensor.py
@@ -133,5 +133,34 @@ def test_random(self):
         self.assertAlmostEqual(tensor.average(x), 1, 3)
 
 
+    def test_radd(self):
+        x = tensor.Tensor((3,))
+        x.set_value(1)
+        y = 1 + x
+        self.assertEqual(tensor.average(y), 2.)
+
+
+    def test_rsub(self):
+        x = tensor.Tensor((3,))
+        x.set_value(1)
+        y = 1 - x
+        self.assertEqual(tensor.average(y), 0.)
+
+
+    def test_rmul(self):
+        x = tensor.Tensor((3,))
+        x.set_value(1)
+        y = 2 * x
+        self.assertEqual(tensor.average(y), 2.)
+
+
+    def test_rdiv(self):
+        x = tensor.Tensor((3,))
+        x.set_value(1)
+        y = 2 / x
+        self.assertEqual(tensor.average(y), 2.)
+
+
+
 if __name__ == '__main__':
     unittest.main()
diff --git a/test/singa/test_memory.cc b/test/singa/test_memory.cc
index 33a374724..8a6101575 100644
--- a/test/singa/test_memory.cc
+++ b/test/singa/test_memory.cc
@@ -25,6 +25,164 @@
 #include "singa/singa_config.h"
 #include "singa/utils/timer.h"
 #include "singa/utils/cuda_utils.h"
+#include <stdlib.h>
+
+TEST(CppMemPool, Compare) {
+	singa::CppMemPool pool;
+	const int numOfOuterLoops =1000;
+	const int numOfInnerLoops = 100;
+	const size_t allocSize = 1024; 
+	int** pp = new int*[numOfInnerLoops];
+	singa::Block** ppBlk = new singa::Block*[numOfInnerLoops];
+	
+	double alloc_time = 0;
+	double free_time = 0;
+	time_t start,end;
+	singa::Timer t;
+  for (int i = 0; i < numOfOuterLoops; i++) {
+		start = clock();
+		for(int j = 0; j < numOfInnerLoops; j++) {
+    	pp[j] = (int*)malloc(allocSize);
+		}
+		end = clock();
+		alloc_time += end-start;
+		start = clock();
+		for(int j = 0; j < numOfInnerLoops; j++) {
+    	free(pp[j]);
+		}
+		end = clock();
+		free_time += end-start;
+  }
+  int kernel_time = t.Elapsed<singa::Timer::Milliseconds>();
+	
+	t.Tick();
+	alloc_time = free_time = 0;
+  for (int i = 0; i < numOfOuterLoops; i++) {
+		start = clock();
+		for(int j = 0; j < numOfInnerLoops; j++) {
+			ppBlk[j] = pool.Malloc(allocSize);
+		}
+		end = clock();
+		alloc_time += end-start;
+		start = clock();
+		for(int j = 0; j < numOfInnerLoops; j++) {
+    	pool.Free(ppBlk[j]);
+		}
+		end = clock();
+		free_time += end-start;
+  }
+  int mempool_time = t.Elapsed<singa::Timer::Milliseconds>();
+	EXPECT_GT(kernel_time,mempool_time);
+	delete pp;
+	delete ppBlk;
+}
+
+// this tests allocated a number of memory blocks in the memory pool
+TEST(CppMemPool, Malloc) {
+	singa::CppMemPool pool;
+	const int numOfTests = 1024;
+	const size_t dataSizeSmall = 1000;
+	const size_t dataSizeLarge = 2000;
+	singa::Block** pptr = new singa::Block*[numOfTests];
+
+	for(int i = 0; i < numOfTests; i++) {
+		const size_t dataSize = (i%2) ? dataSizeSmall : dataSizeLarge;
+		pptr[i] = pool.Malloc(dataSize);
+		int* data = static_cast<int*>(pptr[i]->mutable_data());
+		for(int idx = 0; idx < (int)dataSize/4; idx++) {
+			data[idx] = i;
+		}
+		data = static_cast<int*>(pptr[i]->mutable_data());
+		int sum = 0;
+		for(int idx = 0; idx < (int)dataSize/4; idx++) {
+			sum += data[idx];
+		}
+		CHECK_EQ(sum,i*dataSize/4);
+	}
+	for(int i = 0; i < numOfTests; i++) {
+		pool.Free(pptr[i]);
+	}
+	delete[] pptr;
+}
+
+
+// we allocate 1024 memory blocks
+// subsequently, we randomly free 512 blocks and after that allocate them back to the pool
+TEST(CppMemPool, RandomFree) {
+	singa::CppMemPool pool;
+	const int numOfTests = 1024;
+	const size_t dataSizeSmall = 1000;
+	const size_t dataSizeLarge = 2000;
+	singa::Block** pptr = new singa::Block*[numOfTests];
+
+	for(int i = 0; i < numOfTests; i++) {
+		const size_t dataSize = (i%2) ? dataSizeSmall : dataSizeLarge;
+		pptr[i] = pool.Malloc(dataSize);
+		int* data = static_cast<int*>(pptr[i]->mutable_data());
+		for(int idx = 0; idx < (int)dataSize/4; idx++) {
+			data[idx] = i;
+		}
+		data = static_cast<int*>(pptr[i]->mutable_data());
+		int sum = 0;
+		for(int idx = 0; idx < (int)dataSize/4; idx++) {
+			sum += data[idx];
+		}
+		CHECK_EQ(sum,i*dataSize/4);
+	}
+
+	// randomized free pointers
+	int* randomPool = new int[numOfTests];
+	for(int i = 0; i < numOfTests; i++) {
+		randomPool[i] = i;
+	}
+	int iter = 0;
+	while(iter != numOfTests/2) { // random free half of the memory blocks
+		int pos = std::rand() % (numOfTests-iter);
+		int i = randomPool[pos];
+		std::swap(randomPool[pos],randomPool[numOfTests-1-iter]);
+		
+		// check value before deletion
+		const size_t dataSize = (i%2) ? dataSizeSmall : dataSizeLarge;
+		int* data = static_cast<int*>(pptr[i]->mutable_data());
+		for(int idx = 0; idx < (int)dataSize/4; idx++) {
+			data[idx] = i;
+		}
+		data = static_cast<int*>(pptr[i]->mutable_data());
+		int sum = 0;
+		for(int idx = 0; idx < (int)dataSize/4; idx++) {
+			sum += data[idx];
+		}
+		CHECK_EQ(sum,i*dataSize/4);
+
+		pool.Free(pptr[i]);
+		iter++;
+	}
+	
+	// test the unfreed memory block value
+	for(int pos = 0; pos < numOfTests/2; pos++) {
+		int i = randomPool[pos];
+		const size_t dataSize = (i%2) ? dataSizeSmall : dataSizeLarge;
+		int* data = static_cast<int*>(pptr[i]->mutable_data());
+		for(int idx = 0; idx < (int)dataSize/4; idx++) {
+			data[idx] = i;
+		}
+		data = static_cast<int*>(pptr[i]->mutable_data());
+		int sum = 0;
+		for(int idx = 0; idx < (int)dataSize/4; idx++) {
+			sum += data[idx];
+		}
+		CHECK_EQ(sum,i*dataSize/4);
+	}
+
+	for(int pos = numOfTests/2; pos < numOfTests; pos++) {
+		int i = randomPool[pos];
+		const size_t dataSize = (i%2) ? dataSizeSmall : dataSizeLarge;
+		pptr[i] = pool.Malloc(dataSize);
+	}
+	
+	delete[] randomPool;
+	delete[] pptr;
+}
 
 #ifdef USE_CUDA
 /*