spectrum slicing slepc4py issue: No method getinertia for Mat of type seqaij

[qlyan913]

I am trying to solve an eigenvalue problem on unit interval using the spectrum slicing. But I got the following errors:

Traceback (most recent call last):
  File "/home/grad_A_div/1d/main_slicing.py", line 172, in <module>
    EPS, nconv, Bsc, V=eigen_solver_slicing(mesh,A,deg,sigma_0,sigma_1,bctype,flag2)
  File "/home/grad_A_div/1d/solver.py", line 178, in eigen_solver_slicing
    Eps.solve()
  File "slepc4py/SLEPc/EPS.pyx", line 1266, in slepc4py.SLEPc.EPS.solve
petsc4py.PETSc.Error: error code 56
[0] EPSSolve() at /home/firedrake/src/slepc/src/eps/interface/epssolve.c:134
[0] EPSSetUp() at /home/firedrake/src/slepc/src/eps/interface/epssetup.c:349
[0] EPSSetUp_KrylovSchur() at /home/firedrake/src/slepc/src/eps/impls/krylov/krylovschur/krylovschur.c:106
[0] EPSSetUp_KrylovSchur_Slice() at /home/firedrake/src/slepc/src/eps/impls/krylov/krylovschur/ks-slice.c:338
[0] EPSSliceGetEPS() at /home/firedrake/src/slepc/src/eps/impls/krylov/krylovschur/ks-slice.c:216
[0] EPSSetUp() at /home/firedrake/src/slepc/src/eps/interface/epssetup.c:349
[0] EPSSetUp_KrylovSchur() at /home/firedrake/src/slepc/src/eps/impls/krylov/krylovschur/krylovschur.c:106
[0] EPSSetUp_KrylovSchur_Slice() at /home/firedrake/src/slepc/src/eps/impls/krylov/krylovschur/ks-slice.c:392
[0] EPSSliceGetInertia() at /home/firedrake/src/slepc/src/eps/impls/krylov/krylovschur/ks-slice.c:255
[0] MatGetInertia() at /home/firedrake/src/petsc/src/mat/interface/matrix.c:9244
[0] No support for this operation for this object type
[0] No method getinertia for Mat of type seqaij

The setup of the eigen solver is as followings:

    V = FunctionSpace(mesh, 'Lagrange', deg)
    u = TrialFunction(V)
    v = TestFunction(V)
    b = dot(grad(u), grad(v))*dx
    m = u*v*dx
    uh = Function(V)
    B = assemble(b)
    M = assemble(m)
    Bsc, Msc = B.M.handle, M.M.handle
    # create SLEPc eigensolver
    Eps = SLEPc.EPS().create()
    Eps.setOperators(Bsc, Msc )
    # Set problem type to be generalized Hermitian
    Eps.setProblemType(SLEPc.EPS.ProblemType.GHEP)
    Eps.setType(SLEPc.EPS.Type.KRYLOVSCHUR)
    Eps.setInterval(sigma_0,sigma_1)
    Eps.setWhichEigenpairs(SLEPc.EPS.Which.ALL)
    # set the spectral transform of the EPS to shift-and-invert
    ST = Eps.getST()
    ST.setType(SLEPc.ST.Type.SINVERT)
    ksp = ST.getKSP()
    ksp.setType(PETSc.KSP.Type.PREONLY)
    pc = ksp.getPC()
    pc.setType(PETSc.PC.Type.CHOLESKY)
    Eps.setST(ST)
    Eps.solve()
    nconv = Eps.getConverged()

If I replaced the spectrum slicing by finding the eigenvalues closest to a target, then everything works well. So, I guess the main issue is about " No method getinertia for Mat of type seqaij". Any helps are appreciated! Thanks.

[connorjward]

It looks like only symmetric matrix types are supported for that operation: https://petsc.org/release/manualpages/Mat/MatGetInertia/

You could try running assemble(XXX, mat_type="sbaij") but I think this might fail as we normally assume a restricted set of matrix types.

[qlyan913]

yeah, I tried the mat_type="sbaij", and it gives the error: ValueError: Unrecognised matrix type, 'sbaij'

[qlyan913]

I don't know why, but if I do the following (convert MAT to 'mpisbaij'), it works well:

 Bsc, Msc = B.M.handle, M.M.handle
 B_petsc = Bsc.convert('mpisbaij')
 M_petsc = Msc.convert('mpisbaij')
 # create SLEPc eigensolver
 Eps = SLEPc.EPS().create()
 Eps.setOperators(B_petsc, M_petsc)

[connorjward]

That was going to be my next suggestion. I think this is the best solution while sbaij is unsupported in assemble(). If this is important to you then please open an issue.

[qlyan913]

I am good with it. Thanks for the suggestion.