#include #include // define function to be applied coefficient-wise double ramp(double x) { if (x > 0) return x; else return 0; } int main(int, char**) { Eigen::Matrix4d m1 = Eigen::Matrix4d::Random(); std::cout << m1 << std::endl << "becomes: " << std::endl << m1.unaryExpr(std::ptr_fun(ramp)) << std::endl; return 0; }