KSPMonitorSingularValue#

Prints the two norm of the true residual and estimation of the extreme singular values of the preconditioned problem at each iteration.

Synopsis#

#include "petscksp.h" 
PetscErrorCode KSPMonitorSingularValue(KSP ksp, PetscInt n, PetscReal rnorm, PetscViewerAndFormat *vf)

Logically Collective on ksp

Input Parameters#

  • ksp - the iterative context

  • n - the iteration

  • rnorm - the two norm of the residual

  • vf - The viewer context

Options Database Key#

  • -ksp_monitor_singular_value - Activates KSPMonitorSingularValue()

Notes#

The CG solver uses the Lanczos technique for eigenvalue computation, while GMRES uses the Arnoldi technique; other iterative methods do not currently compute singular values.

This is not called directly by users, rather one calls KSPMonitorSet(), with this function as an argument, to cause the monitor to be used during the KSP solve.

See Also#

KSPComputeExtremeSingularValues(), KSPMonitorSingularValueCreate()

Level#

intermediate

Location#

src/ksp/ksp/interface/iterativ.c

Examples#

src/snes/tutorials/ex30.c.html


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Index of all KSP routines
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Index of all manual pages