#include #include using Eigen::MatrixXd; using Eigen::VectorXd; int main() { MatrixXd m(3,3); for (int row = 0; row < 3; ++row) for (int column = 0; column < 3; ++column) m(row, column) = row + 0.01 * column; VectorXd v = VectorXd::Ones(3); std::cout << m * v << std::endl; }