[petsc-users] About MatTransposeMatMult

[Hong Zhang]

Joon :

> Dear Jed,
>
> Hello. I modified my code using MatTranspose and MatMatMult, and it works
> well.
> BTW, the result of the multiplication of seqaij and seqdense was seqdense.
> I thought C should be seqaij when A is seqaij and B is seqdense in C=A*B.
>

When B is dense, C=A*B is a dense matrix.

Is the way to get seqaij just seqaij*seqaij?
>
Why do you want store a dense matrix in sparse format?

Hong

>
> ----- Original Message -----
> From: "Joon Hee Choi" <choi240 at purdue.edu>
> To: "Jed Brown" <jedbrown at mcs.anl.gov>
> Cc: petsc-users at mcs.anl.gov
> Sent: Thursday, September 26, 2013 2:45:38 PM
> Subject: Re: [petsc-users] About MatTransposeMatMult
>
> > Thank you. I think MatMatMult runs well for multiplication between
> seqaij and seqdense.
>
> > Joon
>
> ----- Original Message -----
> From: "Jed Brown" <jedbrown at mcs.anl.gov>
> To: "Karl Rupp" <rupp at mcs.anl.gov>, "Joon Hee Choi" <choi240 at purdue.edu>,
> petsc-users at mcs.anl.gov
> Cc: "Hong Zhang" <hzhang at mcs.anl.gov>
> Sent: Thursday, September 26, 2013 11:01:42 AM
> Subject: Re: [petsc-users] About MatTransposeMatMult
>
> >> Karl Rupp <rupp at mcs.anl.gov> writes:
>
> >>> Hi,
> >>>
> >>> I am trying to calculate M = X^T * B. X is a seqaij and B is a
> seqdense matrix.
> >>>
> >>> This is not yet allowed in the latest 3.4. release.
>
> >> You can explicitly transpose X:
>
> >>  MatTranspose(X,MAT_INITIAL_MATRIX,&Xt);
>
> >> and then use MatMatMult.
>
> >>> However, I used MatTransposeMatMult() but I got an error. Can someone
> why I got the >>> error and how I should modify my code? I am attaching my
> simple code, error message, >>> and result. Thank you very much.
> >>>
> >>> Do you use the master branch from our Bitbucket repository? It contains
> >>> the commit where Hong added the respective functionality:
> >>>
> https://bitbucket.org/petsc/petsc/commits/8949adfd119cb1d44c9fb5cf3dc01f4b6a02252d
>
> >> This is only for MPI.  Hong, can you expose
> MatTransposeMatMult_SeqAIJ_SeqDense?
>
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