PETSc version 3.15.5
PCShellSetPreSolve
Sets routine to apply to the operators/vectors before a KSPSolve() is applied. This usually does something like scale the linear system in some application specific way. 
Synopsis
#include "petscpc.h" 
PetscErrorCode  PCShellSetPreSolve(PC pc,PetscErrorCode (*presolve)(PC,KSP,Vec,Vec))
Logically Collective on PC
Input Parameters
|  | pc | - the preconditioner context | 
|  | presolve | - the application-provided presolve routine | 
Calling sequence of presolve
   PetscErrorCode presolve (PC,KSP ksp,Vec b,Vec x)
|  | pc | - the preconditioner, get the application context with PCShellGetContext() | 
|  | xin | - input vector | 
|  | xout | - output vector | 
Notes
the function MUST return an error code of 0 on success and nonzero on failure.
See Also
 PCShellSetApplyRichardson(), PCShellSetSetUp(), PCShellSetApplyTranspose(), PCShellSetPostSolve(), PCShellSetContext()
Level
developer
Location
src/ksp/pc/impls/shell/shellpc.c
Implementations
PCShellSetPreSolve_Shell(PC pc,PetscErrorCode (*presolve) in src/ksp/pc/impls/shell/shellpc.c
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages