#include <unsupported/Eigen/MatrixFunctions>
#include <iostream>
using namespace Eigen;
std::complex<double> expfn(std::complex<double> x, int)
{
return std::exp(x);
}
int main()
{
const double pi = std::acos(-1.0);
MatrixXd A(3,3);
A << 0, -pi/4, 0,
pi/4, 0, 0,
0, 0, 0;
std::cout << "The matrix A is:\n" << A << "\n\n";
std::cout << "The matrix exponential of A is:\n"
<< A.matrixFunction(expfn) << "\n\n";
}