[petsc-users] SLEPc Eigenvalue problem - Zero Pivot

venkatesh g venkateshgk.j at gmail.com
Thu May 14 12:29:24 CDT 2015


I am trying to use ARPACK. will it help?

It is not linking Arpack however, when I give ./configure
--with-arpack-dir=..... command from manual.

Venkatesh

On Thu, May 14, 2015 at 10:54 PM, Jose E. Roman <jroman at dsic.upv.es> wrote:

>
> El 14/05/2015, a las 19:13, venkatesh g escribió:
>
> > Hi,
> > 1. I am not calling EPSSetFromOptions in source code. I am using the
> ex7.c given in the SLEPc webpage.
> > 2. A-matrix is not singular. Only B is singular.
> > 3. I will try with MUMPS.
> > 4. Matrix sizes are same as in Matlab. If B is not singular it is giving
> same result as Matlab, but if B is singular it gives the zero pivot issue
> which Matlab doesnt give.
> > So is there a way ?
> >
>
> The ex7.c example calls EPSSetFromOptions(). If it is not called, then
> command-line options are ignored.
>
> It is strange that you get zero pivots when factoring A-sigma*B for
> different values of sigma. Try with MUMPS.
>
> Jose
>
>
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