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About unpreconditioned residuals in Left Preconditioned GMRES
- To: petsc-users@xxxxxxxxxxx
- Subject: About unpreconditioned residuals in Left Preconditioned GMRES
- From: jiaxun hou <jiaxun_hou@xxxxxxxxxxxx>
- Date: Sat, 2 Feb 2008 20:49:03 +0800 (CST)
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- Reply-to: petsc-users@xxxxxxxxxxx
- Sender: owner-petsc-users@xxxxxxxxxxx
Hi everyone,
I want to use the Left Preconditioned GMRES to solve a linear system, and the stopping criterion must be based on the actual residuals (b-Ax). But the GMRES codes of PETSc seems to use the preconditioned residuals (B^-1(b-Ax)) only. In addition, when I set KSPSetNormType(ksp,KSP_NORM_UNPRECONDITIONED), I receive the error message: "Currently can use GMRES with only preconditioned residual (right preconditioning not coded)". So, is there any way to set stopping criterion based on the actual residuals?
Best regards,
Jiaxun
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