I don't know where to ask the question but since I am implementing an algorithm using this library I think is more appropriate here:
I've been using Spectra for generalized eigen values problems specifically I've been using SymGEigsSolver and I went with it, it seems to work ok. I came across however SymGEigsShiftSolver which seems to solve a slightly different problem therefore I wonder what the difference are and what is reccomended based on what situation (from an actual programming perspective).
I think more theoretical questions are more suitable for mathoverlow or mathexchange.
Can anyone clarify when should I use one or the other? Is the Shift Solver more stable or converges faster than the normal Solver?