[petsc-users] Slepc: Nonlinear eigenvalue problem

[Jose E. Roman]

If eigenvalues are complex then NLEIGS also needs to work in complex arithmetic because it needs a region of the complex plane containing the wanted eigenvalues. It seems that complex arithmetic is the only change in your problem.

Jose


> El 22 oct 2018, a las 22:01, Manav Bhatia <bhatiamanav at gmail.com> escribió:
> 
> Thanks, Jose. 
> 
> How difficult would it be to add the support for the general case (if at all possible)? 
> 
> My eigenvalue problem is of the form shown in the attachment. Beta is the eigenvalue and X_s^\Delta is the eigenvector. While some of the matrices are known, others are defined only as matrix vector products. 
> 
> I am interested in eigenvalues with the largest real part. I expect to find complex eigenvalues, although for a small subset of cases these will be real. 
> 
> What is your recommendation for attacking this problem with the nonlinear eigenvalue support in Slepc? 
> 
> Would appreciate your guidance. 
> 
> Regards,
> Manav
> 
> <PastedGraphic-1.pdf>
> 
> 
>> On Oct 22, 2018, at 2:40 PM, Jose E. Roman <jroman at dsic.upv.es> wrote:
>> 
>> 
>> 
>>> El 22 oct 2018, a las 21:05, Manav Bhatia <bhatiamanav at gmail.com> escribió:
>>> 
>>> Hi, 
>>> 
>>>  I am exploring the nonlinear eigenvalue problem solver in Slepc. 
>>> 
>>>  From the notes in "Sec 6.4: Retrieving the Solution”, it appears that if I expect to find complex eigenpairs then I must compile the library (and Petsc) with complex scalars. Is that correct? 
>>> 
>>>  Is there a way to include support for complex eigenpairs in a library complied with real scalars? 
>>> 
>>> Regards,
>>> Manav
>>> 
>>> 
>> 
>> Currently, the only combination that supports complex eigenpairs with real scalars is the split form for the nonlinear function with the NLEIGS solver.
>> 
>> Jose
>