[petsc-users] clarification on extreme eigenvalues from KSPComputeEigenvalues

[feng wang]

Dear All,

I am using the KSPComputeEigenvalues to understand the performance of my preconditioner, and I am using the right-preconditioned GMRES with ASM. In the user guide, it says this routine computes the extreme eigenvalues of the preconditioned operator. If I understand it correctly, these eigenvalues are the ones furthest away from (1,0)? If the preconditioning is perfect, all the eigenvalues should be (1,0).

Thanks,
Feng
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