Expose paddle.framework by pybind11 (PaddlePaddle#2793)

* Expose paddle.framework by pybind11

* Export paddle.framework.{Scope, Variable} to paddle.v2.framework.core.
* See python/paddle/v2/framework/tests/test_scope.py for Python usage
* See paddle/pybind/pybind.cc for C++ bind code.

* add copyright

.gitignore

@@ -19,3 +19,6 @@ third_party/
 
 # clion workspace.
 cmake-build-*
+
+# generated while compiling
+python/paddle/v2/framework/core.so

CMakeLists.txt

@@ -97,6 +97,7 @@ include(external/swig)      # download, build, install swig
 include(external/warpctc)   # download, build, install warpctc
 include(external/any)       # download libn::any
 include(external/eigen)     # download eigen3
+include(external/pybind11)    # download pybind11
 
 include(cudnn)              # set cudnn libraries, must before configure
 include(configure)          # add paddle env configuration

cmake/external/pybind11.cmake

@@ -0,0 +1,30 @@
+INCLUDE(ExternalProject)
+
+SET(PYBIND_SOURCE_DIR ${THIRD_PARTY_PATH}/pybind)
+
+INCLUDE_DIRECTORIES(${PYBIND_SOURCE_DIR}/src/extern_pybind/include)
+
+ExternalProject_Add(
+        extern_pybind
+        ${EXTERNAL_PROJECT_LOG_ARGS}
+        GIT_REPOSITORY  "https://github.com/pybind/pybind11.git"
+        GIT_TAG         "v2.1.1"
+        PREFIX          ${PYBIND_SOURCE_DIR}
+        UPDATE_COMMAND  ""
+        CONFIGURE_COMMAND ""
+        BUILD_COMMAND     ""
+        INSTALL_COMMAND   ""
+        TEST_COMMAND      ""
+)
+
+if (${CMAKE_VERSION} VERSION_LESS "3.3.0")
+    set(dummyfile ${CMAKE_CURRENT_BINARY_DIR}/pybind_dummy.c)
+    file(WRITE ${dummyfile} "const char * dummy_any = \"${dummyfile}\";")
+    add_library(pybind STATIC ${dummyfile})
+else()
+    add_library(pybind INTERFACE)
+endif()
+
+add_dependencies(pybind extern_pybind)
+
+LIST(APPEND external_project_dependencies pybind)

cmake/external/python.cmake

@@ -18,6 +18,9 @@ INCLUDE(python_module)
 FIND_PACKAGE(PythonInterp 2.7)
 IF(WITH_PYTHON)
     FIND_PACKAGE(PythonLibs 2.7)
+    # Fixme: Maybe find a static library. Get SHARED/STATIC by FIND_PACKAGE.
+    ADD_LIBRARY(python SHARED IMPORTED GLOBAL)
+    SET_PROPERTY(TARGET python PROPERTY IMPORTED_LOCATION ${PYTHON_LIBRARIES})
 ENDIF(WITH_PYTHON)
 
 SET(py_env "")

cmake/flags.cmake

@@ -109,7 +109,9 @@ set(COMMON_FLAGS
     -Wno-unused-function
     -Wno-error=literal-suffix
     -Wno-error=sign-compare
-    -Wno-error=unused-local-typedefs)
+    -Wno-error=unused-local-typedefs
+    -Wno-error=parentheses-equality # Warnings in Pybind11
+)
 
 set(GPU_COMMON_FLAGS
     -fPIC

paddle/CMakeLists.txt

@@ -15,6 +15,7 @@ if(Boost_FOUND)
   add_subdirectory(memory)
   add_subdirectory(platform)
   add_subdirectory(framework)
+  add_subdirectory(pybind)
 endif()
 
 if(WITH_C_API)

paddle/pybind/CMakeLists.txt

@@ -0,0 +1 @@
+cc_library(paddle_pybind SHARED SRCS pybind.cc DEPS pybind python)

paddle/pybind/pybind.cc

@@ -0,0 +1,46 @@
+/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserve.
+
+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/framework/scope.h>
+#include <pybind11/pybind11.h>
+
+namespace py = pybind11;
+namespace pd = paddle::framework;
+
+PYBIND11_PLUGIN(core) {
+  py::module m("core", "C++ core of Paddle Paddle");
+
+  py::class_<pd::Variable>(m, "Variable", R"DOC(Variable Class.
+
+All parameter, weight, gradient are variables in Paddle.
+)DOC")
+      .def("is_int", [](const pd::Variable& var) { return var.IsType<int>(); })
+      .def("set_int",
+           [](pd::Variable& var, int val) -> void {
+             *var.GetMutable<int>() = val;
+           })
+      .def("get_int",
+           [](const pd::Variable& var) -> int { return var.Get<int>(); });
+
+  py::class_<pd::Scope, std::shared_ptr<pd::Scope>>(m, "Scope")
+      .def(py::init<const std::shared_ptr<pd::Scope>&>())
+      .def("get_var",
+           &pd::Scope::GetVariable,
+           py::return_value_policy::reference)
+      .def("create_var",
+           &pd::Scope::CreateVariable,
+           py::return_value_policy::reference);
+
+  return m.ptr();
+}

python/CMakeLists.txt

@@ -26,10 +26,17 @@ endif(WITH_GOLANG)
 configure_file(${CMAKE_CURRENT_SOURCE_DIR}/setup.py.in
     ${CMAKE_CURRENT_BINARY_DIR}/setup.py)
 
+
+add_custom_command(OUTPUT ${PROJ_ROOT}/python/paddle/v2/framework/core.so
+        COMMAND cmake -E copy $<TARGET_FILE:paddle_pybind> ${PROJ_ROOT}/python/paddle/v2/framework/core.so
+        DEPENDS paddle_pybind)
+add_custom_target(copy_paddle_pybind ALL DEPENDS ${PROJ_ROOT}/python/paddle/v2/framework/core.so)
+
+
 add_custom_command(OUTPUT ${OUTPUT_DIR}/.timestamp
     COMMAND env ${py_env} ${PYTHON_EXECUTABLE} setup.py bdist_wheel
     COMMAND ${CMAKE_COMMAND} -E touch ${OUTPUT_DIR}/.timestamp
-    DEPENDS gen_proto_py framework_py_proto ${PY_FILES} ${external_project_dependencies} ${COPY_PADDLE_MASTER})
+    DEPENDS gen_proto_py copy_paddle_pybind framework_py_proto ${PY_FILES} ${external_project_dependencies} ${COPY_PADDLE_MASTER})
 
 add_custom_target(paddle_python ALL DEPENDS
     ${OUTPUT_DIR}/.timestamp)

python/paddle/v2/framework/tests/CMakeLists.txt

@@ -1 +1 @@
-add_python_test(test_framework test_protobuf.py)
+add_python_test(test_framework test_protobuf.py test_scope.py)

python/paddle/v2/framework/tests/test_protobuf.py

@@ -24,3 +24,7 @@ def test_all(self):
         attr.type = attr_type_lib.FLOAT
         op_proto.type = "cos"
         self.assertTrue(op_proto.IsInitialized())
+
+
+if __name__ == "__main__":
+    unittest.main()

python/paddle/v2/framework/tests/test_scope.py

@@ -0,0 +1,37 @@
+import paddle.v2.framework.core
+import unittest
+
+
+class TestScope(unittest.TestCase):
+    def test_create_destroy(self):
+        paddle_c = paddle.v2.framework.core
+        scope = paddle_c.Scope(None)
+        self.assertIsNotNone(scope)
+        scope_with_parent = paddle_c.Scope(scope)
+        self.assertIsNotNone(scope_with_parent)
+
+    def test_none_variable(self):
+        paddle_c = paddle.v2.framework.core
+        scope = paddle_c.Scope(None)
+        self.assertIsNone(scope.get_var("test"))
+
+    def test_create_var_get_var(self):
+        paddle_c = paddle.v2.framework.core
+        scope = paddle_c.Scope(None)
+        var_a = scope.create_var("var_a")
+        self.assertIsNotNone(var_a)
+        self.assertIsNotNone(scope.get_var('var_a'))
+        scope2 = paddle_c.Scope(scope)
+        self.assertIsNotNone(scope2.get_var('var_a'))
+
+    def test_var_get_int(self):
+        paddle_c = paddle.v2.framework.core
+        scope = paddle_c.Scope(None)
+        var = scope.create_var("test_int")
+        var.set_int(10)
+        self.assertTrue(var.is_int())
+        self.assertEqual(10, var.get_int())
+
+
+if __name__ == '__main__':
+    unittest.main()

python/setup.py.in

@@ -29,7 +29,9 @@ setup(name='paddle',
       description='Parallel Distributed Deep Learning',
       install_requires=setup_requires,
       packages=packages,
-      package_data={'paddle.v2.master': ['libpaddle_master.so'], },
+      package_data={'paddle.v2.master': ['libpaddle_master.so'],
+            'paddle.v2.framework': ['core.so']
+      },
       package_dir={
           '': '${CMAKE_CURRENT_SOURCE_DIR}',
           # The paddle.v2.framework.proto will be generated while compiling.