[petsc-users] Petsc has generated inconsistent data - Divide by zero!

[TAY wee-beng]

Hi Jed,

Ok thanks. Btw, is it better to solve my x/y eqns together? How can I do 
that?

Is there any examples which I can follow?

Yours sincerely,

TAY wee-beng


On 10/7/2011 12:51 AM, Jed Brown wrote:
> On Sat, Jul 9, 2011 at 17:43, TAY wee-beng <zonexo at gmail.com 
> <mailto:zonexo at gmail.com>> wrote:
>
>     Sorry about that. I just run interactively to get the output.
>
>     Now I issued :
>
>     mpiexec -np 1 ./a.out  -ksp_type gmres -ksp_gmres_restart 1000
>     -ksp_gmres_modifiedgramschmidt -ksp_monitor_true_residual
>     -ksp_view -pc_type asm -sub_pc_type lu > log1
>
>
> Your matrix is singular which implies a bug in your assembly code, 
> probably in the way you impose boundary conditions. Switch to a very 
> small problem size (e.g. 4 cells) and debug it until the matrix is 
> correct and non-singular.
>
> You should also check the error codes so the code doesn't try to keep 
> going after a fatal error.
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