fix eigen external project

add eigen as external project.
add very simple eigen unit test to test building/linking

cmake/external_eigen.cmake

+# Copyright 2017 Nervana Systems Inc.
+# 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.
+
+cmake_minimum_required(VERSION 3.7)
+
+# Enable ExternalProject CMake module
+include(ExternalProject)
+
+set(EXTERNAL_INSTALL_LOCATION ${CMAKE_BINARY_DIR}/external)
+
+#----------------------------------------------------------------------------------------------------------
+# Download and install GoogleTest ...
+#----------------------------------------------------------------------------------------------------------
+
+# The 'BUILD_BYPRODUCTS' argument was introduced in CMake 3.2.
+ExternalProject_Add(
+    eigen
+    URL http://bitbucket.org/eigen/eigen/get/3.3.3.zip
+    # PREFIX ${CMAKE_CURRENT_BINARY_DIR}/eigen
+    INSTALL_COMMAND make install
+    UPDATE_COMMAND ""
+    CMAKE_ARGS -DCMAKE_INSTALL_PREFIX=${EXTERNAL_INSTALL_LOCATION}
+    )
+
+#----------------------------------------------------------------------------------------------------------
+
+ExternalProject_Get_Property(eigen source_dir binary_dir)
+
+set(EIGEN_INCLUDE_DIR "${EXTERNAL_INSTALL_LOCATION}/include/Eigen3" PARENT_SCOPE)

test/CMakeLists.txt

@@ -13,7 +13,12 @@
 
 include_directories(
     SYSTEM
-    "${GTEST_INCLUDE_DIR}"
+    ${GTEST_INCLUDE_DIR}
+    ${EIGEN_INCLUDE_DIR}
+    )
+    
+include_directories(
+    ${NGRAPH_INCLUDE_DIR}
     )
 
 set (SRC
@@ -25,6 +30,7 @@ set (SRC
     uuid.cpp
     topological_sort.cpp
     op.cpp
+    eigen.cpp
 )
 
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
@@ -35,7 +41,7 @@ add_executable(unit-test ${SRC})
 target_link_libraries(unit-test ngraph libgtest pthread)
 target_link_libraries(unit-test ${CMAKE_DL_LIBS})
 
-add_dependencies(unit-test ngraph libgtest)
+add_dependencies(unit-test ngraph libgtest eigen)
 
 add_custom_target(check
 	COMMAND ${PROJECT_BINARY_DIR}/test/unit-test

test/eigen.cpp

+// ----------------------------------------------------------------------------
+// Copyright 2017 Nervana Systems Inc.
+// 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
+// ----------------------------------------------------------------------------
+
+#include <iostream>
+#include <Eigen/Dense>
+
+#include "gtest/gtest.h"
+
+using Eigen::MatrixXd;
+
+TEST(eigen, simple)
+{
+    MatrixXd m(2,2);
+    m(0,0) = 3;
+    m(1,0) = 2.5;
+    m(0,1) = -1;
+    m(1,1) = m(1,0) + m(0,1);
+    EXPECT_FLOAT_EQ(m(1,1), 1.5);
+}

third-party/CMakeLists.txt

@@ -12,3 +12,4 @@
 # limitations under the License.
 
 include( ../cmake/external_gtest.cmake )
+include( ../cmake/external_eigen.cmake )