petsc-3.3-p7 2013-05-11


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).


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

Input Parameters

pc - iterative context obtained from PCCreate()
flg - PETSC_TRUE indicates the guess is non-zero, PETSC_FALSE indicates the guess is zero


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, PCREDUNDANT and PCHMPI 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.


PC, set, initial guess, nonzero

See Also

PCGetInitialGuessNonzero(), PCSetInitialGuessKnoll(), PCGetInitialGuessKnoll()

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