Eigen求特征值与特征向量

这里列举三种方式求矩阵的特征值与特征向量

#include <stdio.h>
#include <stdlib.h>
#include<Eigen/Eigen>

using namespace std;
using namespace Eigen;

void main()
{
	MatrixXd m(3, 3);
	m << 1,-2,2,
		 -2,-2,4,
		 2,4,-2;
	cout << m << endl << endl;

	EigenSolver<MatrixXd> es(m);
	cout << "第一种：" << endl;
	cout << "特征值为："  << endl;
	cout << es.eigenvalues() << endl;
	cout << "特征向量为：" <<endl;
	cout << es.eigenvectors() << endl << endl;

	cout << "第二种：" << endl;
	Matrix3d D = es.pseudoEigenvalueMatrix();
	Matrix3d V = es.pseudoEigenvectors();

	cout << D << endl << endl;
	cout << V << endl << endl;

	cout << "第三种：" << endl;
	MatrixXd value= es.eigenvalues().real();
	MatrixXd vector= es.eigenvectors().real();

	cout << value<< endl << endl;
	cout << vector<< endl << endl;
	}

运行结果