[petsc-users] SLEPc Eigenvalue problem - Zero Pivot

[Jose E. Roman]

This has nothing to do with ARPACK.


El 14/05/2015, a las 19:29, venkatesh g escribió:

> 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
> 
>