[petsc-users] How to efficiently assemble this matrix?

[Jed Brown]

Italo Tasso <bichinhoverde at spwinternet.com.br> writes:

> Thanks Matt and Jed. After further analysis, it turns out that the
> operation I must perform is even more complicated than what I initially
> described. So direct assembly seems to be the only option. I ended up using
> MatGetRow and MatSetValues.

Depending in what it is, a new "MatTAIJ" format that we're working on
might serve you well.  This currently deals with matrices of the form

  I \otimes S + J \otimes T

where J is a distributed sparse matrix and S and T are (smallish)
non-distributed matrices.  The matrix you originally described is

  J \otimes I_4
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 818 bytes
Desc: not available
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20140717/30eb73d1/attachment.pgp>