[petsc-users] Block size

[Eric Chamberland]

On 05/22/2015 11:36 AM, Barry Smith wrote:
>
>     Eric,
>
 > to squeeze the largest problem you can run you would use the point 
format and it will be somewhat slower but at least you will not run out 
of memory.

Ok, my algorithm is already general and can do both.  But my main worry is:

Do all preconditionners are able to handle "sparse blocks" when 
block_size > 1 in {SEQ,MPI}AIJ matrix?  Do they still have some gain 
with "sparse blocks"?  (for example, algebraic multi-grid will be able 
to pick lines "per-block" when block_size > 1 but blocks are "sparses")?

Maybe the answer is trivial, but we were discussing it here and we got 
different positions on this..

Thanks,

Eric