[petsc-users] Drastic increase in memory usage between DMDA_STENCIL_BOX and DMDA_STENCIL_STAR

[Barry Smith]

On Mar 18, 2014, at 8:04 PM, Mani Chandra <mc0710 at gmail.com> wrote:

> Hi,
> 
> I see a 4x increase in the memory usage when I change from DMDA_STENCIL_STAR to DMDA_STENCIL_BOX. Attached are the outputs of -log_summary which shows a huge increase in the matrix memory usage. Is this expected?
> 
> On a different note, suppose I am running a serial calculation with no need to exchange data but I am using corner node information,

   How can you use corner node information if you are not exchanging it? You will be using incorrect data


> do I need to use DMDA_STENCIL_BOX? Would the jacobian when computed using colored finite differences be correctly represented if I use corner information but still use DMDA_STENCIL_STAR?
> 
> Thanks,
> Mani
> 
> 
> <dmda_stencil_box.txt><dmda_stencil_star.txt>