Which version of SLEPc are you using? You should get an error unless you have configure PETSc with a parallel direct linear solver. Which option did you use to configure PETSc?
Send the output when using the option -eps_view_pre Jose > El 23 ago 2022, a las 2:11, Patrick Alken <patrick.al...@geomag.info> > escribió: > > I am trying to solve a symmetric generalized eigenproblem with slepc (n = > 40500) using 8 processors. The command I use is: > > mpiexec -n 8 ./main -eps_nev 10 -eps_target 0 -st_type sinvert > > The program assembles the two matrices (A,B), sets up the eigensolver and > then calls EPSSolve. The issue is that the matrix assembly runs fine in > parallel. And for about 1 minute or so, the EPSSolve call uses all 8 > processors (according to the top program). But then after around 1 minute or > so, the program collapses to just 1 thread and just runs that way for a long > time (still in the EPSSolve call). > > Is there a way to diagnose what is going on, and how to make the program use > all 8 processors for the eigensolver? > > >