OK, I see. I will do it, thank you! I will let you know if I get any result.

On Mon, Aug 17, 2020 at 7:06 PM Wolfgang Bangerth <bange...@colostate.edu>
wrote:

> On 8/17/20 6:01 PM, yuesu jin wrote:
> >      I did nothing to verify those properties. because the single thread
> CG
> > solver converged well. I used  different preconditioners in parallel
> version
> > and single thread version. In the parallel version I used block Jacobi
> and in
> > the single thread version I used Jacobi. How can I check if the parallel
> > blocked sparse matrix is/ isn't symmetrical and positive definite?
>
> Think of tests such as this:
> * run on 1 processor, multiply a vector w of all 1s from the right, and
> output
> the resulting vector v=Aw on all processors
> * run on >1 processors and repeat
> Are the vectors the same for both cases? The matrix should be the same
> regardless of partitioning, but is it?
>
> * repeat the same with Tvmult (multiplication from the left)
>
> You can probably come up with many similar tests that check properties of
> the
> matrix, comparing between the single-processor and multiple-processor
> cases.
> The point is that you may not know the exact answer, but you know that the
> two
> cases should result in the same output.
>
> Best
>   W.
>
> --
> ------------------------------------------------------------------------
> Wolfgang Bangerth          email:                 bange...@colostate.edu
>                             www: http://www.math.colostate.edu/~bangerth/
>
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>


-- 
Yuesu Jin,
Ph.D student,
University of Houston,
College of Natural Sciences and Mathematics,
Department of Earth and Atmospheric Sciences,
Houston, Texas 77204-5008
346-404-2062

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