[petsc-users] Skipping data when reading from binary file

[Peder Jørgensgaard Olesen]

Thank you for your quick reply.


I've had to change away from HDF5 to Binary format at an earlier stage in my work due to the former not working well with what I needed, so I would prefer to stick with the binary format.

I had a quick view at the code for some of the Viewer-routines, but I'm not well versed in gleaning information about header sizes from that. Hints about what I'm looking for there would be appreciated.


Best regards

Peder

________________________________
Fra: Matthew Knepley <knepley at gmail.com>
Sendt: 4. oktober 2021 15:37:08
Til: Peder Jørgensgaard Olesen
Cc: petsc-users at mcs.anl.gov
Emne: Re: [petsc-users] Skipping data when reading from binary file

On Mon, Oct 4, 2021 at 9:26 AM Peder Jørgensgaard Olesen via petsc-users <petsc-users at mcs.anl.gov<mailto:petsc-users at mcs.anl.gov>> wrote:

Hello

I have a binary file in which a mix of different objects is stored (Vecs, Mats, PetscInts). I can read each element just fine using VecLoad, MatLoad, and PetscIntView, provided they're read in the order in which they were put in the binary. What I would like to do is to skip the reading of any unneeded element, instead proceeding directly to the next one. I tried using PetscBinarySeek() for this, as shown in the attached code. This produces segmentation faults, suggesting that the file pointer isn't going where I want it to.

There is header information you also have to skip for each object.

We can go over the sizes  for that (it is best just to look at the code), but that is fragile. A more robust way to achieve this random
access is to use HDF5 and name the objects.

  Thanks,

     Matt

Any suggestions as to what I'm doing wrong here?


Best regards,

Peder


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Peder Jørgensgaard Olesen
PhD student
Department of Mechanical Engineering

pjool at mek.dtu.dk<mailto:pjool at mek.dtu.dk>
Koppels Allé
Building 403, room 105
2800 Kgs. Lyngby
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