petsc-3.5.1 2014-07-24
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KSPSetNormType

Sets the norm that is used for convergence testing.

Synopsis

#include "petscksp.h" 
PetscErrorCode  KSPSetNormType(KSP ksp,KSPNormType normtype)
Logically Collective on KSP

Input Parameter

ksp - Krylov solver context
normtype - one of
  KSP_NORM_NONE - skips computing the norm, this should only be used if you are using
                the Krylov method as a smoother with a fixed small number of iterations.
                Implicitly sets KSPConvergedSkip as KSP convergence test.
                Supported only by CG, Richardson, Bi-CG-stab, CR, and CGS methods.
  KSP_NORM_PRECONDITIONED - the default for left preconditioned solves, uses the l2 norm
                of the preconditioned residual
  KSP_NORM_UNPRECONDITIONED - uses the l2 norm of the true b - Ax residual, supported only by
                CG, CHEBYSHEV, and RICHARDSON, automatically true for right (see KSPSetPCSide())
                preconditioning..
  KSP_NORM_NATURAL - supported  by KSPCG, KSPCR, KSPCGNE, KSPCGS

Options Database Key

-ksp_norm_type <none,preconditioned,unpreconditioned,natural> - Notes: Currently only works with the CG, Richardson, Bi-CG-stab, CR, and CGS methods.

Keywords

KSP, create, context, norms

See Also

KSPSetUp(), KSPSolve(), KSPDestroy(), KSPConvergedSkip(), KSPSetCheckNormIteration()

Level:advanced
Location:
src/ksp/ksp/interface/itcreate.c
Index of all KSP routines
Table of Contents for all manual pages
Index of all manual pages