**petsc-dev 2014-07-25**

# PCSetInitialGuessNonzero

Tells the iterative solver that the initial guess is nonzero; otherwise PC assumes the initial guess is to be zero (and thus zeros it out before solving).
### Synopsis

#include "petscksp.h"
PetscErrorCode PCSetInitialGuessNonzero(PC pc,PetscBool flg)

Logically Collective on PC

### Input Parameters

### Notes

This is a weird function. Since PC's are linear operators on the right hand side they
CANNOT use an initial guess. This function is for the "pass-through" preconditioners
PCKSP and PCREDUNDANT and causes the inner KSP object to use the nonzero
initial guess. Not currently working for PCREDUNDANT, that has to be rewritten to use KSP.

### Keywords

PC, set, initial guess, nonzero

### See Also

PCGetInitialGuessNonzero(), PCSetInitialGuessKnoll(), PCGetInitialGuessKnoll()

**Level:**Developer

Location:src/ksp/pc/interface/precon.c

Index of all PC routines

Table of Contents for all manual pages

Index of all manual pages