Hello Ram,

> *However the problem is i need to specify EPSProblemType to be
> EPS_GHEP since only this option helps to get an M orthonormal eigen
> vectors. The issue is i currently don't know of an option in the
> slepc wrappers to specify this input. It will be of great help if you
> can help me figuring this issue out.

Currently there is no built-in option to symmetry the symmetry of the
matrix from the SLEPcWrappers. This is something we would like (and
will) to add in the near future. However, the EPSSetProblemType can be
controlled on the command line; see the Slepc documentation:
http://www.grycap.upv.es/slepc/documentation/current/docs/manualpages/EPS/EPSSetProblemType.html

In any case, specifying GHEP (or a different EPSProblemType) *only
makes use of symmetries internally within the Slepc solver*. Not
specifying this option should still give you the same eigenvectors
back, since they are a result of the matrices you solve (that is,
assuming you use these flags correctly). The default with the
SLEPcWrappers is not to exploit symmetries, which should always work.

An alternative to specify the eigenproblem symmetry type is to
investigate the SLEPcWrappers::SpectralTransformation class. Hint: More
often than not (for Schroedinger eigenspectrum problems), KrylovSchur
with a TransformationShiftInvert works exceptionally well.

Hope that helps.

Best,
        Toby

-- 
Toby D. Young

Assistant Professor Philosophy & Physics
Polish Academy of Sciences
www:   http://www.ippt.gov.pl/~tyoung
skype: stenografia

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