eigenvalues and eigen vector c++ code example
Example 1: matrix eigen c++ example
#include <iostream>
#include <Eigen/Dense>
using namespace Eigen;
int main()
{
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);
std::cout << "Here is the matrix m:\n" << m << std::endl;
VectorXd v(2);
v(0) = 4;
v(1) = v(0) - 1;
std::cout << "Here is the vector v:\n" << v << std::endl;
}
Example 2: eigenvalue of matrix c++ using Eigen
#include <eigen3/Eigen/Eigenvalues>
#include <iostream>
int main(){
Eigen::Matrix<double, 2, 2> A;
A << 0, 2, 1, 0;
Eigen::EigenSolver<Eigen::Matrix<double, 2,2> > s(A);
std::cout << A << std::endl;
std::cout << "eigenvalues:" << std::endl;
std::cout << s.eigenvalues()(0) << std::endl;
std::cout << "eigenvectors=" << std::endl;
std::cout << s.eigenvectors() << std::endl;
return(0);
}