[petsc-dev] Faulty logic in MatHYPRESetPreallocation?

[Pierre Jolivet]

Stefano,
Please find attach a trivial example that will segfault from within hypre if you put back on the (IMHO unnecessary) hypre_AuxParCSRMatrixNeedAux(aux_matrix) = 1 in PR #1305.
You need to use two processes or more.

Thanks,
Pierre



> On 29 Dec 2018, at 10:13 AM, Stefano Zampini <stefano.zampini at gmail.com> wrote:
> 
> Barry,
> 
> Probably this is an oversight from me. When I coded the MATHYPRE class, I did not make much attention to the preallocation. Also, hypre did not seem very robust to matrix reusage at the time. Take a look at the comments at line 85 in ex115 from mat tests. Probably Pierre's fix will curate that problem too. 
> 
> Stefano
> 
> Il giorno Sab 22 Dic 2018, 06:30 Smith, Barry F. <bsmith at mcs.anl.gov <mailto:bsmith at mcs.anl.gov>> ha scritto:
> 
>    Stefeno,
> 
>     Doe this look right to you?
> 
>     Thanks
> 
>     Barry
> 
> 
> > On Dec 17, 2018, at 3:18 AM, Pierre Jolivet via petsc-dev <petsc-dev at mcs.anl.gov <mailto:petsc-dev at mcs.anl.gov>> wrote:
> > 
> > Hello,
> > I am not sure the hypre routines are called in the right order in MatHYPRESetPreallocation.
> > Indeed, attached, you’ll find two Massif logs, one with the current order (massif.out.bad), and the other (massif.out.better) with the attached patch applied.
> > In the former, you can see at the snapshot #31 that there is a call to hypre_CTAlloc in hypre_AuxParCSRMatrixInitialize (aux_parcsr_matrix.c:163).
> > This means that hypre is allocating memory as if it was not aware of the number of nonzero per row, even though I supply in my application the two arrays dnnz and onnz.
> > 
> > Am I missing something?
> > 
> > Thanks,
> > Pierre
> > 
> > <massif.out.bad><massif.out.better><patch-hypre.txt>
> 

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