PCDiagonalScaleLeft#
Scales a vector by the left scaling as needed by certain time-stepping codes.
Synopsis#
#include "petscksp.h"
PetscErrorCode PCDiagonalScaleLeft(PC pc, Vec in, Vec out)
Logically Collective
Input Parameters#
pc - the preconditioner context
in - input vector
out - scaled vector (maybe the same as in)
Notes#
The system solved via the Krylov method is
D M A D^{-1} y = D M b for left preconditioning or
D A M D^{-1} z = D b for right preconditioning
PCDiagonalScaleLeft() scales a vector by D. PCDiagonalScaleRight() scales a vector by D^{-1}.
If diagonal scaling is turned off and in is not out then in is copied to out
See Also#
PCCreate(), PCSetUp(), PCDiagonalScaleSet(), PCDiagonalScaleRight(), PCDiagonalScale()
Level#
intermediate
Location#
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages