KSPSetOptionsPrefix

Sets the prefix used for searching for all KSP options in the database.

Synopsis

#include "petscksp.h" 
PetscErrorCode KSPSetOptionsPrefix(KSP ksp, const char prefix[])

Logically Collective

Input Parameters

• ksp - the Krylov context

• prefix - the prefix string to prepend to all KSP option requests

Notes

A hyphen (-) must NOT be given at the beginning of the prefix name. The first character of all runtime options is AUTOMATICALLY the hyphen.

For example, to distinguish between the runtime options for two different KSP contexts, one could call

      KSPSetOptionsPrefix(ksp1,"sys1_")
      KSPSetOptionsPrefix(ksp2,"sys2_")

This would enable use of different options for each system, such as

      -sys1_ksp_type gmres -sys1_ksp_rtol 1.e-3
      -sys2_ksp_type bcgs  -sys2_ksp_rtol 1.e-4

See Also

KSP: Linear System Solvers, KSP, KSPAppendOptionsPrefix(), KSPGetOptionsPrefix(), KSPSetFromOptions()

Level

intermediate

Location

src/ksp/ksp/interface/itcl.c

Examples

src/ksp/ksp/tutorials/ex49.c
src/ksp/ksp/tutorials/ex43.c
src/ksp/ksp/tutorials/ex1.c
src/ksp/ksp/tutorials/ex70.c
src/ksp/ksp/tutorials/ex59.c
src/ksp/ksp/tutorials/ex42.c
src/tao/tutorials/ex3.c

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