src/matrix_vector/Matrix.hpp
explicit MatrixBase(size_type r = 0, size_type c = 0)
      : Super(S::eval(r) * S::eval(c == 0 ? r : c)),
        _rows(S::eval(r)),
        _cols(S::eval(c == 0 ? r : c))
    {}
/// \brief Default constructor.
/// allocates memory for a matrix of size \p r x \p c
\brief Default constructor.
allocates memory for a matrix of size \p r x \p c
\ brief Default constructor . allocates memory for a matrix of size \ p r x \ p c
explicit MatrixBase(size_type r = 0, size_type c = 0)
      : Super(S::eval(r) * S::eval(c == 0 ? r : c)),
        _rows(S::eval(r)),
        _cols(S::eval(c == 0 ? r : c))
    {}
explicit MatrixBase ( size_type r = 0 , size_type c = 0 ) : Super ( S :: eval ( r ) * S :: eval ( c == 0 ? r : c ) ) , _rows ( S :: eval ( r ) ) , _cols ( S :: eval ( c == 0 ? r : c ) ) { }
\brief Default constructor.
\ brief Default constructor .