Templated function inside class, error when moving to header file?

Question

I have this templated function inside a class. This is implemented in a file named Mtry.cpp

class Mtry
{
public:
    template <typename DerivedV, typename DerivedF, typename Scalar>
    static void cotmatrix(
        const Eigen::MatrixBase<DerivedV> & V,
        const Eigen::MatrixBase<DerivedF> & F,
        Eigen::SparseMatrix<Scalar>& L);
};



template <typename DerivedV, typename DerivedF, typename Scalar>
void Mtry::cotmatrix(
    const Eigen::MatrixBase<DerivedV> & V,
    const Eigen::MatrixBase<DerivedF> & F,
    Eigen::SparseMatrix<Scalar>& L)
{
    // Implementation...
}

I have no problem when using that code. However, if I move the declaration towards Mtry.hpp and the implementation to Mtry.cpp I get an undefined reference

Mtry.hpp:

class Mtry
{
public:
    template <typename DerivedV, typename DerivedF, typename Scalar>
    static void cotmatrix(
            const Eigen::MatrixBase<DerivedV> & V,
            const Eigen::MatrixBase<DerivedF> & F,
            Eigen::SparseMatrix<Scalar>& L);
};

Mtry.cpp

template <typename DerivedV, typename DerivedF, typename Scalar>
void Mtry::cotmatrix(
    const Eigen::MatrixBase<DerivedV> & V,
    const Eigen::MatrixBase<DerivedF> & F,
    Eigen::SparseMatrix<Scalar>& L)
{
    // Implementation...
}

I saw this question where it states that the first code should work. However I couldn't find how to separate the code properly into header and source. How should it be done?

Templated function inside class, error when moving to header file?

0 Answers0