[Trilinos-Users] [EXTERNAL] Tpetra::CrsMatrix caching related to C= A^T B and D = A*C

Denis Davydov davydden at gmail.com
Mon Sep 24 09:46:39 EDT 2018

Hi Chris,

Sorry to bother, but can you please reply to comment on the questions (1) and (3) below?
You said I can run C=A^T B with C being fillComplete() but as I mention there is an exception thrown.
I am also still curious what’s the distribution of C=A^T B when both A and B and distributed row-wise.
Perhaps based on our discussion the documentation of Tpetra::MatrixMatrix::Multiply() could be improved.


> On 14 Sep 2018, at 11:48, Denis Davydov <davydden at gmail.com> wrote:
> Hi Chris,
>> On 12 Sep 2018, at 16:00, Siefert, Christopher <csiefer at sandia.gov <mailto:csiefer at sandia.gov>> wrote:
>> 1) The way this is usually used is row-wise, matching A.
> but I am doing A^T B where both A and B are distributed in MPI row-wise only. 
> So what’s the distribution of  C = A^T B in this case?
>> 3) Running with fillComplete'd matrices for is going to be much, much faster than running w/o fillComplete.  You do *not* need to do what you're doing.  Could you try removing the resumeFill and redoing the timing?
> looks like I have to do this, otherwise I get:
> Exception on processing:
> .../trilinos-12.12.1-oezdv7yojfjmbqdbsy57mvcmogm7qfrj/Trilinos-trilinos-release-12-12-1/packages/tpetra/core/ext/TpetraExt_MatrixMatrix_def.hpp:191:
> Throw number = 1
> Throw test that evaluated to true: C.isFillActive() == false
> Error!
> Aborting!
> the check is here: 
> https://github.com/trilinos/Trilinos/blob/master/packages/tpetra/core/ext/TpetraExt_MatrixMatrix_def.hpp#L204 <https://github.com/trilinos/Trilinos/blob/master/packages/tpetra/core/ext/TpetraExt_MatrixMatrix_def.hpp#L204> 
> So to me it looks like it’s not possible to call C = A^T B with C being fillComplete().
> Regards,
> Denis.

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