[petsc-users] MatMPIBAIJSetPreallocationCSR i and j indices

Lisandro Dalcin dalcinl at gmail.com
Sun Sep 29 11:22:44 CDT 2013

On 29 September 2013 17:31, Barry Smith <bsmith at mcs.anl.gov> wrote:
>    I forgot that MatSetValuesBlocked() takes row oriented input even within the blocks. So if we simply call MatSetOption(mat,MAT_ROW_ORIENTED,PETSC_FALSE) on the matrix after it is created then the storage should work as I originally planned.
>   Barry
> I found this discussion values(bs,nblockcols,bs,nblockrows)  very confusing. MatMPIBAIJSetPreallocationCSR() doesn't take a square block of values so I didn't see what you are talking about. You must be talking about each internal call to MatSetValuesBlocked_MPIBAIJ(B,1,&row,ncols,icols,svals,INSERT_VALUES) where it puts in one block row of values with each call.

Yes, that's what I was talking about. And yes, if you have
column-oriented block values [e.g, in fotran you use an array
VALUES(bs,bs,nnz) ] and use MatSetOption(), you are fine and
MatMPIBAIJSetPreallocationCSR() will do the right thing. Otherwise
(e.g, you are in C and use VALUES[nnz][bs][bs]), feeding
MatMPIBAIJSetPreallocationCSR() with these values will not work. I
guess we have to live with that.

Lisandro Dalcin
Predio CONICET-Santa Fe
Colectora RN 168 Km 472, Paraje El Pozo
3000 Santa Fe, Argentina
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