Use of lpNorm in Eigen

Question

I am trying to do some L_p norm calculations within a template function something of the sort

template<typename Number>
Number foo(const Eigen::MatrixBase<Number>& matrix)
{
  return matrix.lpNorm<1>(); 
}

However, CLang throws an error "expected expression" at the end of the line if I try to call foo(matrix). If I work with concretely defined (double) matrices, lpNorm works just fine. How do I go about with this case?

Answer 1

Classical C++ mistake. The solution is to use the template keyword as follow:

return matrix.template lpNorm<1>();

See the details.