KSPSetFromOptions

Sets KSP options from the options database. This routine must be called before KSPSetUp() if the user is to be allowed to set the Krylov type.

Synopsis

#include "petscksp.h" 
int KSPSetFromOptions(KSP ksp)
Collective on KSP

Input Parameters

ksp -the Krylov space context

Options Database Keys

                      convergence test (say you always want to run with 5 iterations) to 
                      save on communication overhead
                   preconditioned - default for left preconditioning 
                   unpreconditioned - see KSPSetNormType()
                   natural - see KSPSetNormType()
-ksp_max_it - maximum number of linear iterations
-ksp_rtol rtol - relative tolerance used in default determination of convergence, i.e. if residual norm decreases by this factor than convergence is declared
-ksp_atol atol - absolute tolerance used in default convergence test, i.e. if residual norm is less than this then convergence is declared
-ksp_divtol tol - if residual norm increases by this factor than divergence is declared
-ksp_norm_type - none - skip norms used in convergence tests (useful only when not using
-ksp_knoll - compute initial guess by applying the preconditioner to the right hand side
-ksp_cancelmonitors - cancel all previous convergene monitor routines set
-ksp_monitor - print residual norm at each iteration
-ksp_xmonitor - plot residual norm at each iteration
-ksp_vecmonitor - plot solution at each iteration
-ksp_singmonitor - monitor extremem singular values at each iteration

Notes

To see all options, run your program with the -help option or consult the users manual.

Keywords

KSP, set, from, options, database

See Also


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