When the Matrix argument is defined as constant I get

.resize(rows,cols) Matrix const MatrixXd as 'this' argument discards qualifiers error

    void (const Eigen::MatrixXd &X){
    X.resize(cols, rows) }

returns an error but this works as expected:

    void(Eigen::MatrixXd &X){
    X.resize(cols, rows)}

I'm not too familiar with c (other than using it for this class) and am wondering what this means?

Thanks for any pointers.

CodePudding user response：

The warning means that the resize function that you called is not const qualified. The lack of const qualification means that the function cannot be called on a const lvalue. resize is a function that modifies the object. The rough meaning of "const" is that modification isn't allowed.

X is an lvalue reference to const, so non-const qualified functions cannot be called through the reference. You attempted to call a non-const qualified function through the const reference. Since that's not allowed, the compiler told you about the bug.