Nothing special is required for solving a GHEP with singular M, except for setting the problem type as GHEP, see https://slepc.upv.es/documentation/current/src/eps/tutorials/ex13.c.html Jose
> El 16 ago 2020, a las 1:09, Nidish <n...@rice.edu> escribió: > > Hello, > > I'm presently working with a large finite element model with several RBE3 > constraints with "virtual" 6DOF nodes in the model. > > I have about ~36000 3DOF nodes making up my model and about ~10 RBE3 virtual > nodes (which have zero intrinsic mass and stiffness). I've extracted the > matrices from Abaqus. > > The way these constraints are implemented is by introducing static linear > constraints (populating the stiffness matrix) and padding the mass matrix > with zero rows and columns in the rows corresponding to the virtual nodes. So > this leaves me with an eigenproblem of the form, > > K.v = lam*M.v > > where M is singular but the eigenproblem is well defined. Abaqus seems to > solve this perfectly well, but after exporting the matrices, I'm struggling > to get slepc to solve this. The manual talks about deflation, etc., but I > couldn't really understand too much. > > Is there any example code for such a case with a singular matrix where these > procedures are carried out? Or could you provide references/guidances for > approaching the problem? > > Thank you, > Nidish
