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, PetscErrorCode (*presolve)(KSP ksp, Vec rhs, Vec x, void *ctx), void *ctx)
Logically Collective
Input Parameters#
ksp - the solver object
presolve - the function to call before the solve
ctx - an optional context needed by the function
Calling sequence of presolve#
ksp - the
KSPcontextrhs - the right-hand side vector
x - the solution vector
ctx - optional user-provided context
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, KSPSetUp(), KSPSolve(), KSPDestroy(), KSP, KSPSetPostSolve(), PCEISENSTAT, PCPreSolve(), PCPostSolve()
Level#
developer
Location#
src/ksp/ksp/interface/itcreate.c
Index of all KSP routines
Table of Contents for all manual pages
Index of all manual pages