[petsc-users] ISView() in PETSc 3.22

[Matthew Knepley]

On Mon, Sep 30, 2024 at 10:15 PM Adrian Croucher <a.croucher at auckland.ac.nz>
wrote:

> hi, I am testing my (Fortran) code on PETSc 3.22 and have got it to
> build. However I am getting some unusual new behaviour when I write an
> IS to an HDF5 file using ISView().
>
> The attached minimal example shows the issue. It creates a simple
> 10-element IS and writes it to HDF5. With previous versions of PETSc
> this would give me a 10x1 dataset containing the values 0 - 9, as expected.
>
> When I run it with PETSc 3.22 (in serial), I again get the expected
> values written on stdout, so it looks like the IS itself is correct. But
> in the HDF5 file I get a 1x3 dataset containing the values (10,1,0).
>
> Has something changed here?
>

Yes. We now compress IS data sets by default. You can turn it off using
-is_view_compress 0. I am not sure
what the best way to manage this is, but it makes a huge difference in file
size for checkpointing.

  Thanks,

     Matt


> - Adrian
>
> --
> Dr Adrian Croucher
> Senior Research Fellow
> Department of Engineering Science
> Waipapa Taumata Rau / University of Auckland, New Zealand
> email: a.croucher at auckland.ac.nz
> tel: +64 (0)9 923 4611
>


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experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener

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