Function eigs does not work when matrix is defective

[ishaanjain]

Describe the bug
When a matrix has only one eigenvector, the function eigs does not work.

To Reproduce
The matrix [[1, 1], [0, 1]] is a simple shear matrix that has the eigenvector [0,1].
However, eigs([[1, 1], [0, 1]]) returns an error.

[josdejong]

Thanks for reporting.

Help debugging this issue with eigs would be welcome. Anyone?

[DarshanDixit05]

Hi @josdejong👋, I want to work on the issue. Can you please assign it to me?

[josdejong]

Thanks a lot Darshan! Please let me know if you need any help.

[gwhitney]

Likely duplicate of #2879

[gwhitney]

Works with #2879 fix, so confirmed to be a duplicate. Closing.