[petsc-users] fieldsplit error

[Barry Smith]

On Dec 27, 2013, at 9:25 PM, subramanya sadasiva <potaman at outlook.com> wrote:

> Hi, 
> I have a nonlinear system with 6 variables grouped in two sets of 3. I am trying to get a fieldsplit preconditioner working . I have the following options set up 
> 
> -pc_type fieldsplit
> -pc_fieldsplit_type multiplicative
> -fieldsplit_0_fields 0,2,4
> -fieldsplit_1_fields 1,3,5

    These should be -pc_fieldsplit_0 or 1 _fields   0,2,4   or 1,3,5   the reason is these are options for pc_fieldsplit not for a particular sub solve

> -fieldsplit_0_ksp cg
> -fieldsplit_1_ksp cg

   These should be -fieldsplit_0 or 1 _ksp_type cg

> -fieldsplit_0_pc hypre
> -fieldsplit_1_pc hypre

   These should be -fieldsplit_0 or 1 _pc_type hypre   But I don’t think hypre ensures a symmetric preconditioner so you probably use gmres above instead of cg

  Barry

> 
> However, I get the following error. My installation of libmesh has block matrices disabled, which I've seen to cause problems with fieldsplit. Any ideas what might cause this error?
> Thanks, 
> Subramanya 
> 
> 
> 
> [0]PETSC ERROR: --------------------- Error Message ------------------------------------
> [0]PETSC ERROR: Petsc has generated inconsistent data!
> [0]PETSC ERROR: Unhandled case, must have at least two fields, not 1!
> [0]PETSC ERROR: ------------------------------------------------------------------------
> [0]PETSC ERROR: Petsc Release Version 3.4.3, unknown 
> [0]PETSC ERROR: See docs/changes/index.html for recent updates.
> [0]PETSC ERROR: See docs/faq.html for hints about trouble shooting.
> [0]PETSC ERROR: See docs/index.html for manual pages.