add test eigen

test_eigen_map/CMakeLists.txt

@@ -0,0 +1,31 @@
+cmake_minimum_required(VERSION 2.8)
+project(test_eigen)
+
+set(CMAKE_BUILD_TYPE Debug)
+set(CMAKE_CXX_FLAGS "-std=c++14 -O3")
+
+list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
+
+# # OpenCV
+# find_package(OpenCV REQUIRED)
+# include_directories(${OpenCV_INCLUDE_DIRS})
+
+# # Ceres
+# find_package(Ceres REQUIRED)
+# include_directories(${CERES_INCLUDE_DIRS})
+
+# # g2o
+# find_package(G2O REQUIRED)
+# include_directories(${G2O_INCLUDE_DIRS})
+
+# Eigen
+include_directories("/usr/include/eigen3")
+
+add_executable(main main.cpp)
+# target_link_libraries(gaussNewton ${OpenCV_LIBS})
+
+# add_executable(ceresCurveFitting ceresCurveFitting.cpp)
+# target_link_libraries(ceresCurveFitting ${OpenCV_LIBS} ${CERES_LIBRARIES})
+
+# add_executable(g2oCurveFitting g2oCurveFitting.cpp)
+# target_link_libraries(g2oCurveFitting ${OpenCV_LIBS} g2o_core g2o_stuff)

test_eigen_map/main.cpp

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+#include <iostream>
+#include <Eigen/Core>
+#include <Eigen/Dense>
+
+using namespace Eigen;
+using namespace std;
+
+// map 和 vector 的配合怎样的改变 矩阵的形状。
+// 使用map 来从已有内存获得数据 形成一个vector
+typedef Eigen::Map<Eigen::VectorXi> VectorRef;
+// 使用map 来从已有的内存获得数据形成一个vector （const）
+typedef Eigen::Map<const Eigen::VectorXi> ConstVectorRef;
+
+int main(){
+	int num = 11;
+
+	int array[num];
+	// 首先定义一个数组
+	for(int i = 0; i < num; ++i) array[i] = i;
+	// 从array的第一个内存开始把数据映射为一个vector
+	cout << "VectorRef:\n" << VectorRef(array,7) << endl;  
+	/* output
+	VectorRef:
+	0
+	1
+	2
+	3
+	4
+	5
+	6
+	 */
+	// 从array的第二个内存开始把数据映射为一个vector
+	cout << "VectorRef:\n" << VectorRef(array+1,7) << endl;
+	/* VectorRef:
+	1
+	2
+	3
+	4
+	5
+	6
+	7 */
+	// 从array的第一个内存开始把数据映射为一个const vector
+	// cout << "ConstVectorRef :\n" << ConstVectorRef(array,4) << endl;
+
+	VectorRef testvector(array,3);
+	cout << "testvector :\n" << testvector << endl;
+	/* testvector :
+	0
+	1
+	2 */
+
+	ConstVectorRef testconstvector(array,4);
+	cout << "testconstvector :\n" << testconstvector << "\n";
+	cout << "testconstvector.size(): " << testconstvector.size()  << endl;
+	/* testconstvector :
+	0
+	1
+	2
+	3
+	testconstvector.size(): 4
+
+ 	*/
+
+ 	// testconstvector[2] = 4; 
+	// 	 error: lvalue required as left operand of assignment
+
+
+	cout << "Column-major-12:\n" << Map<Matrix<int,2,6> >(array) << endl;
+	/* 
+	Column-major-12:
+	0  2  4  6  8 10
+	1  3  5  7  9  0 */
+
+	cout << "Column-major:\n" << Map<Matrix<int,2,4> >(array) << endl;
+	/* Column-major:
+	0 2 4 6
+	1 3 5 7
+	 */
+
+	cout << "Row-major:\n" << Map<Matrix<int,2,4,RowMajor> >(array) << endl;
+	/* Row-major:
+	0 1 2 3
+	4 5 6 7 */
+
+	cout << "Row-major using stride:\n" <<
+
+	Map<Matrix<int,2,4>, Unaligned, Stride<1,5> >(array) << endl;
+	/* Row-major using stride:
+	0 1 2 3
+	5 6 7 8 */
+}