[petsc-users] SNESComputeJacobianDefaultColor use too much memory

[Barry Smith]

  How many colors are needed?

  You need to produce a breakdown of where all the memory is being used. For example valgrind with the http://valgrind.org/docs/manual/ms-manual.html

  Barry

> On Feb 16, 2016, at 6:45 AM, Rongliang Chen <rongliang.chan at gmail.com> wrote:
> 
> Dear all,
> 
> I am using the DMPlex to solve a PDE on a unstructured mesh and I use the SNESComputeJacobianDefaultColor to compute the Jacobian matrix.
> 
> My code works well for small problems (such as problem with 3.3x10^5 cells using 120 cores) but when I increase the number of cells (2.6x10^6 cells using 1920 cores), I go out of memory in the function MatColoringApply. It shows that one of the cores uses over 11G memory. I think this is unreasonable. Do you have any suggestions for debugging this problem?
> 
> Best regards,
> Rongliang