deterministic behaviour for eigs_sym() and eigs_gen() in ARPACK mode
@matteosecli I've reworked eigs_sym() and eigs_gen() in the 12.6.x branch so the same random initial starting point (residue) is always used, rather than relying on the non-repeatable starting point provided by ARPACK.
This is to make the behaviour of eigs_sym() and eigs_gen() deterministic (ie. provide the same results for the same input).
The change in the starting point is likely to result in slightly different eigenvectors. This applies to both standard operation as well as the shift-invert mode.
Could you test the modified eigs_sym() and eigs_gen() functions to see if they still work correctly for you?
git clone -b 12.6.x --single-branch https://gitlab.com/conradsnicta/armadillo-code.git armadillo-12.6.x