[petsc-users] GAMG PC dependence on right-hand side

[Jed Brown]

John Mousel <john.mousel at gmail.com> writes:

> I have two KSP contexts, helm%ksp and proj%ksp. I switch between the two by
> calling KSPSetOperators. 

Why call KSPSetOperators?  You should be able to call KSPSetOperators
once for helm%ksp and once for proj%ksp, then just call

for each step:
  KSPSolve(helm%ksp, new_rhs, x)
  update new_rhs
  KSPSolve(proj%ksp, new_rhs, y)

> There was no performance difference, just a different answer.

Okay, but both equally accurate up to your convergence tolerance?
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