What do you get for -ksp_view ? You should very likely be using the -pc_type gamg if it is an unstructured grid problem or you are using your own mesh data structure or -pc_type mg if you are using the DMDACreate1/2/3() Barry

On Oct 19, 2014, at 3:58 PM, Alletto, John M <[email protected]> wrote:

All,

I have a 64 bit linux machine with 256 GByte of memory and 30 processors. I am solving Laplace equations and the current solver I am using is taking every bit of memory I have available.

Do you have any suggestions (such as changing precision or changing solvers or something else) in order to reduce my memory footprint?

Many Thanks John