[petsc-users] SLEPc: Setting options for mass matrix KSP in generalised eigenvalue problem

[Cotter, Colin J]

Thanks Jose!


all the best

--cjc

________________________________
From: Jose E. Roman <jroman at dsic.upv.es>
Sent: 16 January 2019 09:55:08
To: Cotter, Colin J
Cc: petsc-users at mcs.anl.gov
Subject: Re: [petsc-users] SLEPc: Setting options for mass matrix KSP in generalised eigenvalue problem

This case is treated in the same way as the (shift-and-invert) spectral transformation. There are nested objects EPS > ST > KSP > PC. By default ST=SHIFT, which is what you need. So you just have to get access to the KSP/PC objects to set options.

Basically you can use ex9.py in slepc4py but use F.setType(F.Type.SHIFT) instead of F.setType(F.Type.PRECOND).

Jose


> El 16 ene 2019, a las 10:32, Cotter, Colin J via petsc-users <petsc-users at mcs.anl.gov> escribió:
>
> Dear PETSc mailing list,
>   A SLEPc question, sorry if this is obvious and I missed something.
>
> How do I set the KSP for the mass matrix M in the generalised eigenvalue problem
> (I'm looking for the eigenvalue with largest magnitude)
>
> Ax = lambda*Mx
>
> ?
>
> I can only find how to set the KSP for a spectral transform.
>
> (I'm actually using slepc4py)
>
> all the best
> -_Colin

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