> El 29 ago 2019, a las 22:20, Povolotskyi, Mykhailo <mpovo...@purdue.edu>
> escribió:
>
> Thank you for suggestion.
>
> Is it interfaced to SLEPC?
No, could be a future project...
>
>
> On 08/29/2019 04:14 PM, Jose E. Roman wrote:
>> I am not an expert in contour integral eigensolvers. I think difficulties
>> come with corners, so ellipses are the best choice. I don't think ring
>> regions are relevant here.
>>
>> Have you considered using ScaLAPACK. Some time ago we were able to address
>> problems of size up to 400k https://doi.org/10.1017/jfm.2016.208
>>
>> Jose
>>
>>
>>> El 29 ago 2019, a las 21:55, Povolotskyi, Mykhailo <mpovo...@purdue.edu>
>>> escribió:
>>>
>>> Thank you, Jose,
>>>
>>> what about rings? Are they better than rectangles?
>>>
>>> Michael.
>>>
>>>
>>> On 08/29/2019 03:44 PM, Jose E. Roman wrote:
>>>> The CISS solver is supposed to estimate the number of eigenvalues
>>>> contained in the contour. My impression is that the estimation is less
>>>> accurate in case of rectangular contours, compared to elliptic ones. But
>>>> of course, with ellipses it is not possible to fully cover the complex
>>>> plane unless there is some overlap.
>>>>
>>>> Jose
>>>>
>>>>
>>>>> El 29 ago 2019, a las 20:56, Povolotskyi, Mykhailo via petsc-users
>>>>> <petsc-users@mcs.anl.gov> escribió:
>>>>>
>>>>> Hello everyone,
>>>>>
>>>>> this is a question about SLEPc.
>>>>>
>>>>> The problem that I need to solve is as follows.
>>>>>
>>>>> I have a matrix and I need a full spectrum of it (both eigenvalues and
>>>>> eigenvectors).
>>>>>
>>>>> The regular way is to use Lapack, but it is slow. I decided to try the
>>>>> following:
>>>>>
>>>>> a) compute the bounds of the spectrum using Krylov Schur approach.
>>>>>
>>>>> b) divide the complex eigenvalue plane into rectangular areas, then
>>>>> apply CISS to each area in parallel.
>>>>>
>>>>> However, I found that the solver is missing some eigenvalues, even if my
>>>>> rectangles cover the whole spectral area.
>>>>>
>>>>> My question: can this approach work in principle? If yes, how one can
>>>>> set-up CISS solver to not loose the eigenvalues?
>>>>>
>>>>> Thank you,
>>>>>
>>>>> Michael.
>>>>>
>
