CODEWITHSUNDEEP
c++templatesgcceigeneigen3
Jan Rüegg
Jan Rüegg

Reputation: 10045

Replacing scalar with template fails

I'm trying to write a function that takes an Eigen::Matrix from either type double or float. This function works fine for floats:

Eigen::Matrix<float, 4, 4> foo(const Eigen::Matrix<float, 4, 4> &T)
{
   Eigen::Matrix<float, 4, 4> result;
   result.block<3,3>(0,0) = T.block<3,3>(0,0).transpose();
   return result;
}

However, as soon as I make the "float" a template:

template <typename Scalar>
inline Eigen::Matrix<Scalar, 4, 4> foo(const Eigen::Matrix<Scalar, 4, 4> &T)
{
   Eigen::Matrix<Scalar, 4, 4> result;
   result.block<3,3>(0,0) = T.block<3,3>(0,0).transpose();
   return result;
}

I get this error with gcc 4.9.1 on linux:

.../utils.hpp: In function 'Eigen::Matrix core::math::foo(const Eigen::Matrix&)': .../utils.hpp:77:47: error: request for member 'transpose' in '(0, 0)', which is of non-class type 'int' result.block<3,3>(0,0) = T.block<3,3>(0,0).transpose();

What could be the problem here?

Upvotes: 0

Views: 90

Answers (1)

Jarod42
Jarod42

Reputation: 217275

Once the function is template some calls are dependent of template and so you have to add some template keyword, try:

template <typename Scalar>
inline Eigen::Matrix<Scalar, 4, 4> foo(const Eigen::Matrix<Scalar, 4, 4> &T)
{
   Eigen::Matrix<Scalar, 4, 4> result;
   result.template block<3,3>(0,0) = T.template block<3,3>(0,0).transpose();
   return result;
}

Upvotes: 3

Related Questions