CODEWITHSUNDEEP
c++templatestypeseigen
Alice Schwarze
Alice Schwarze

Reputation: 579

C++/Eigen: Get type of matrix argument to a template written for MatrixBase

I would like to create a template that takes an Eigen matrix as input and that includes a Cholesky decomposition (LLT in Eigen; see doc) in its body.

template <typename Derived>
double function_with_llt(const MatrixBase<Derived>& m) {
    LLT<m_type> llt_of_input(m); //how do I get m's type?
return 0;
}

The problem is that I need type of the matrix m to declare LLT. Substituting m_type with MatrixBase<Derived> did not work. I could use one of Eigen's dynamic matrix classes (e.g. MatrixXd) for LLT, but I would prefer to have decomposition matrices with fixed dimensions in later computations. Is there some typedef or other trick that could fix this?

Upvotes: 0

Views: 490

Answers (1)

oLen
oLen

Reputation: 5547

I would take the matrix type as a template parameter:

template <typename MatrixType>
double function_with_llt(const MatrixType& m) {
    LLT<MatrixType> llt_of_input(m);
    return 0;
}

Upvotes: 1

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