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Re: Simple question
- To: petsc-users@xxxxxxxxxxx, "Toby D. Young" <tyoung@xxxxxxxxxxx>
- Subject: Re: Simple question
- From: "Matthew Knepley" <knepley@xxxxxxxxx>
- Date: Fri, 28 Sep 2007 08:52:06 -0500
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On 9/28/07, Toby D. Young <tyoung@xxxxxxxxxxx> wrote:
> Hello,
>
> For the function MatIsSymmetric(),
> is it correct to state that PetscTruth returns:
> 1 - true (symmetric)
> 0 - false (nonsymmetric)
Technically, PETSC_TRUE and PETSC_FALSE.
> This is the output I get from test on an Identity matrix.
>
> A simple question perhaps, but I have really confusing results for other
> matrices which are needed to be symmetry verified.
I assume that you have (supposedly) symmetric matrices that are coming
up nonsymmetric? You could put a break point in MatIsTranspose_SeqAIJ()
and see which row is disputed. Alternatively, you could use MatTranspose()
and then output them both with the ASCII viewer and diff. Perhaps your
tolerance is too low.
Matt
> Thanks!
>
> Best,
> Toby
>
> --
>
> Toby D. Young ( Adiunkt )
> Department of Computational Science
> Institute of Fundamental Technological Research, Polish Academy of
> Sciences, Room 206, Swietokrzyska 21, 00-049 Warsaw, POLAND
>
>
--
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