@Mark: Sorry, I totally misunderstood your answer, so my answer to your
answer about petsc versions is non-sense...
@Hong: MatTransposeMatMult gives (Ct*C), no? And I feel that
MatCreateTranspose actually works for mpiaij.
On 24/09/2020 16:16, Zhang, Hong via petsc-users wrote:
Olivier and Matt,
MatPtAP with A=I gives Pt*P, not P*Pt. We have sequential MatRARt
and MatMatTransposeMult(), but no support for mpiaij matrices. The
problem is that we do not have a way to implement C*Ct without
explicitly transpose C in parallel.
We support MatTransposeMatMult (A*Bt) for mpiaij. Can you use this
instead?
Hong
------------------------------------------------------------------------
*From:* petsc-users <petsc-users-boun...@mcs.anl.gov> on behalf of
Zhang, Hong via petsc-users <petsc-users@mcs.anl.gov>
*Sent:* Thursday, September 24, 2020 8:56 AM
*To:* Matthew Knepley <knep...@gmail.com>; Mark Adams <mfad...@lbl.gov>
*Cc:* PETSc <petsc-users@mcs.anl.gov>
*Subject:* Re: [petsc-users] Compute C*Ct using MatCreateTranspose for Ct
Indeed, we do not have MatCreateTranspose for mpaij matrix.
I can adding such support. How soon do you need it?
Hong
------------------------------------------------------------------------
*From:* petsc-users <petsc-users-boun...@mcs.anl.gov> on behalf of
Matthew Knepley <knep...@gmail.com>
*Sent:* Thursday, September 24, 2020 6:12 AM
*To:* Mark Adams <mfad...@lbl.gov>
*Cc:* PETSc <petsc-users@mcs.anl.gov>
*Subject:* Re: [petsc-users] Compute C*Ct using MatCreateTranspose for Ct
On Thu, Sep 24, 2020 at 6:48 AM Mark Adams <mfad...@lbl.gov
<mailto:mfad...@lbl.gov>> wrote:
Is there a way to avoid the explicit transposition of the matrix?
It does not look like we have A*B^T for mpiaij as the error
message says. I am not finding it in the code.
Note, MatMatMult with a transpose shell matrix, I suspect that it
does an explicit transpose internally, or it could notice that you
have C^T*C and we might have that implemented in-place (I doubt
it, but it would be legal and fine to do).
We definitely have
https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatPtAP.html
For now, you can put the identity in for A. It would be nice it we
assumed that when A = NULL.
Patrick, the implementation strategy is broken for the MatProduct
mechanism that was just introduced, so
we cannot see which things are implemented in the documentation. How
would I go about fixing it?
Thanks,
Matt
Many thanks,
Olivier Jamond
--
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
https://www.cse.buffalo.edu/~knepley/
<http://www.cse.buffalo.edu/~knepley/>
