KSPSetPreSolve

Sets a function that is called at the beginning of each KSPSolve(). Used in conjunction with KSPSetPostSolve().

Synopsis

#include "petscksp.h" 
PetscErrorCode KSPSetPreSolve(KSP ksp, KSPPSolveFn *presolve, void *ctx)

Logically Collective

Input Parameters

• ksp - the solver object

• presolve - the function to call before the solve, see KSPPSolveFn

• ctx - an optional context needed by the function

Notes

The function provided here presolve is used to modify the right hand side, and possibly the matrix, of the linear system to be solved. The function provided with KSPSetPostSolve() then modifies the resulting solution of that linear system to obtain the correct solution to the initial linear system.

The functions PCPreSolve() and PCPostSolve() provide a similar functionality and are used, for example with PCEISENSTAT.

See Also

KSP: Linear System Solvers, KSPPSolveFn, KSPSetUp(), KSPSolve(), KSPDestroy(), KSP, KSPSetPostSolve(), PCEISENSTAT, PCPreSolve(), PCPostSolve()

Level

developer

Location

src/ksp/ksp/interface/itcreate.c

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Index of all KSP routines
Table of Contents for all manual pages
Index of all manual pages