Hello everyone,

I just moved from fortran90 with lapack to C++ with Eigen. I know that writing a universal sort function for eigenvalue problem is not possible. But when the matrix is symmetry/Hermitian, the eigenvalues are real numbers. And such kind of matrices are heavily used in physics. So I am wondering whether there is a easy way to sort the real eigenvalues as well as eigenvectors?

Please tell me if the answer is yes. If the answer is no, I am hoping Eigen developers can add such a sort function in the later versions or sort the real eigenvalues automatically. And I am sure that the LAPACK(fortran) Hermitian matrix eigen solver sort the result automatically, and GSL provide a function for sorting Hermitian matrix eigenvalues.

Eigen is one of the most beautiful scientific code that I've ever seen so far Many thanks to the developers.

Hi,

this is already the case, EigenSelfAdjointSolver automatically sorts the eigenvalues in increasing order.

gael

Sorry I didn't see it! Thanks for the help.