On Wednesday, November 2, 2016 at 1:40:17 PM UTC-4, Ralph Smith wrote: > > Eigs uses shift-and-invert for the :sm variant, so it tries to solve M x = > b. Try adding a small sigma parameter. >
Yes, but it really should be able to handle matrices with a nontrivial nullspace ... the nullspace is (part of) exactly what you want, and in principle you can get it efficiently and then project it out.
