tempest/resources/3rdparty/eigen/unsupported/doc/examples/MatrixLogarithm.cpp

#include <unsupported/Eigen/MatrixFunctions>
#include <iostream>

using namespace Eigen;

int main()
{
  using std::sqrt;
  MatrixXd A(3,3);
  A << 0.5*sqrt(2), -0.5*sqrt(2), 0,
       0.5*sqrt(2),  0.5*sqrt(2), 0,
       0,            0,           1;
  std::cout << "The matrix A is:\n" << A << "\n\n";
  std::cout << "The matrix logarithm of A is:\n" << A.log() << "\n";
}