[petsc-users] Using higher order ILU preconditioner

[Kong, Fande]

Calling PCFactorSetMatOrderingType() (or command line option:
-pc_factor_mat_ordering_type) to use RCM or 1WD usually helps me a lot. My
application is based on highly-unstructured meshes.

Fande,

On Thu, Sep 28, 2017 at 2:53 PM, Rachit Prasad <rachitp at vt.edu> wrote:

> Hi,
>
> I am trying to solve a highly ill-conditioned matrix and am unable to get
> convergence when using ILU(0) or Jacobi and SOR preconditioners. I tried to
> implement a higher order ILU by increasing the level of fill-in to 1 by
> calling
>
> call PCFactorSetLevels(pc,1,ierr)
>
> However, when I do that I get the following memory error:
>
> [0]PETSC ERROR: --------------------- Error Message
> ------------------------------------
> [0]PETSC ERROR: Out of memory. This could be due to allocating
> [0]PETSC ERROR: too large an object or bleeding by not properly
> [0]PETSC ERROR: destroying unneeded objects.
> [0]PETSC ERROR: Memory allocated -2147483648 Memory used by process
> -2147483648
> [0]PETSC ERROR: Try running with -malloc_dump or -malloc_log for info.
> [0]PETSC ERROR: Memory requested 18446744071863943168!
>
> While I do understand that increasing the level of fill-in will require
> higher memory, the memory requested seems to be way too high. Am I
> implementing the higher order ILU correctly? Is there any other subroutine
> which I need to call?
>
> Regards,
> Rachit
>
>
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