KSPComputeEigenvaluesExplicitly

Computes all of the eigenvalues of the preconditioned operator using LAPACK.

Synopsis

int KSPComputeEigenvaluesExplicitly(KSP ksp,int nmax,double *r,double *c) 
Collective on KSP

Input Parameter

ksp - iterative context obtained from KSPCreate()
n - size of arrays r and c

Output Parameters

r - real part of computed eigenvalues
c - complex part of computed eigenvalues

Notes

This approach is very slow but will generally provide accurate eigenvalueestimates. This routine explicitly forms a dense matrix representingthe preconditioned operator, and thus will run only for relatively smallproblems, say n < 500.

Many users may just want to use the monitoring routineKSPSingularValueMonitor() (which can be set with option -ksp_singmonitor) to print the singular values at each iteration of the linear solve.

Keywords

KSP, compute, eigenvalues, explicitly

See Also

KSPComputeEigenvalues(), KSPSingularValueMonitor(), KSPComputeExtremeSingularValues()

Location: src/ksp/interface/eige.c
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