Hi all,

I am trying to use the ARPACK wrapper to calculate the eigenvalues of a sparse matrix.

I arrived at this post https://forum.kde.org/viewtopic.php?f=74&t=111782, I have a similar code implementation, except I was trying to use an sparse arry.

The first reply says the class is only available for sparse arrays, but I don't understand how to implement the code. The solution was also not clear.

My sparse array is declared lie this

Code: Select all

SparseMatrix<double> Ho(size,size);

It is later filled by a function.

I am sorry if the problem was not expressed in the most correct way, I am new to this and new to eigen.

just follow the example in viewtopic.php?f=74&t=111782 and then call ev.eigenvalues()/ev.eigenvectors() to get the eigen values/vectors.

You might also consider using spectra: https://github.com/yixuan/spectra