[petsc-users] BiCGStab and right preconditioning

[Barry Smith]

   Are you running a PETSc example? Please send exactly what options you are using to run the code. 

   On a test case it is working correctly for me, we need your help to reproduce the problem.

   Barry

On Jan 18, 2011, at 2:06 AM, Kathrin Burckhardt wrote:

> Dear all,
> 
> I have a problem using BiCGStab with right preconditioning.
> 
> Solving my system using gmres everything looks ok:
> 
>  0 KSP preconditioned resid norm 4.490868831255e-04 true resid norm 4.490868831255e-04 ||Ae||/||Ax|| 6.402973612108e-01
>  1 KSP preconditioned resid norm 2.641616638766e-04 true resid norm 2.641616638766e-04 ||Ae||/||Ax|| 3.766353965541e-01
> 
> 
> Solving it with bcgs, however, I got:
> 
> 0 KSP preconditioned resid norm 4.490868831255e-04 true resid norm 1.222737120188e+01 ||Ae||/||Ax|| 1.743349407273e+04
>  1 KSP preconditioned resid norm 1.801799542022e-04 true resid norm 1.222736696074e+01 ||Ae||/||Ax|| 1.743348802582e+04
> 
> What could be wrong?
> 
> Looking forward to your help,
> Kathrin