FastDeploy/third_party/eigen/doc/snippets/tut_arithmetic_redux_minmax.cpp

Matrix3f m = Matrix3f::Random();
std::ptrdiff_t i, j;
float minOfM = m.minCoeff(&i, &j);
cout << "Here is the matrix m:\n" << m << endl;
cout << "Its minimum coefficient (" << minOfM << ") is at position (" << i
     << "," << j << ")\n\n";

RowVector4i v = RowVector4i::Random();
int maxOfV = v.maxCoeff(&i);
cout << "Here is the vector v: " << v << endl;
cout << "Its maximum coefficient (" << maxOfV << ") is at position " << i
     << endl;