petsc-master 2014-10-19
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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 on PC

Input Parameters

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

Keywords

PC

See Also

PCCreate(), PCSetUp(), PCDiagonalScaleSet(), PCDiagonalScaleRight(), PCDiagonalScale()

Level:intermediate
Location:
src/ksp/pc/interface/precon.c
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages

pc - the preconditioner context
in - input vector + out - scaled vector (maybe the same as in)