[petsc-users] SLEPc: HDF5 support for SVD/EPSValuesView?

Fri Jun 4 09:59:26 CDT 2021

Excellent question. It may well be some quirk of my own setup that somehow makes VecView run rather sluggishly, making it hardly relevant to the general case.

- Peder

________________________________
Fra: Matthew Knepley <knepley at gmail.com>
Sendt: 4. juni 2021 16:48:05
Til: Peder Jørgensgaard Olesen
Cc: Jose E. Roman; petsc-users at mcs.anl.gov
Emne: Re: [petsc-users] SLEPc: HDF5 support for SVD/EPSValuesView?

On Fri, Jun 4, 2021 at 10:28 AM Peder Jørgensgaard Olesen <pjool at mek.dtu.dk<mailto:pjool at mek.dtu.dk>> wrote:

What Matt suggests could perhaps be used as a workaround, though it appears neither elegant nor in my experience efficient. I may be wrong on this.

Why is it not efficient?

  Thanks,

     Matt

My attempted solution was to use a binary viewer instead, but I can't find a clear way to retrieve values thus stored with PETSc, as these do not lend themselves to be read using VecLoad. Again one might go about that by wrapping them inside a vector and send that to the viewer, which just brings us back around to the original problem.

- Peder

________________________________
Fra: Jose E. Roman <jroman at dsic.upv.es<mailto:jroman at dsic.upv.es>>
Sendt: 4. juni 2021 16:01:04
Til: Matthew Knepley
Cc: Peder Jørgensgaard Olesen; petsc-users at mcs.anl.gov<mailto:petsc-users at mcs.anl.gov>
Emne: Re: [petsc-users] SLEPc: HDF5 support for SVD/EPSValuesView?

The problem is that here I am writing PetscReal's not PetscScalar's, and in EPS I am writing PetscComplex even in real scalars. That is why I did not implement it as you are suggesting.

Jose

> El 4 jun 2021, a las 15:56, Matthew Knepley <knepley at gmail.com<mailto:knepley at gmail.com>> escribió:
>
> On Fri, Jun 4, 2021 at 9:31 AM Jose E. Roman <jroman at dsic.upv.es<mailto:jroman at dsic.upv.es>> wrote:
> I could try and adapt the HDF5 code in PETSc for this, but I am no HDF5 expert. Furthermore I am busy at the moment, so it is faster if you could prepare a merge request with this addition.
>
> I think the easiest thing is to wrap a Vec around the values and just VecView() it into the same HDF5 file.
>
>   THanks,
>
>     Matt
>
> Jose
>
>
> > El 4 jun 2021, a las 13:10, Peder Jørgensgaard Olesen via petsc-users <petsc-users at mcs.anl.gov<mailto:petsc-users at mcs.anl.gov>> escribió:
> >
> > Hello
> >
> > In SLEPc one may write singular vectors to an HDF5 file using SVDVectorsView(), but a similar option doesn't seem to work for singular values using SVDValuesView(). The values are viewed correctly using other viewers, but nothing is seemingly produced when using an HDF5 viewer. Looking at the source code seems to confirm this, and suggests that there is a similar situation with EPS.
> >
> > Is this correct, and if so, might there be plans to include such functionality in future releases?
> >
> > Med venlig hilsen / Best Regards
> >
> > Peder Jørgensgaard Olesen
> > PhD Student, Turbulence Research Lab
> > Dept. of Mechanical Engineering
> > Technical University of Denmark
> > Koppels Allé
> > Bygning 403, Rum 105
> > DK-2800 Kgs. Lyngby
>
>
>
> --
> What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
> -- Norbert Wiener
>
> https://www.cse.buffalo.edu/~knepley/

--
What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/<http://www.cse.buffalo.edu/~knepley/>
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