petsc-3.8.4 2018-03-24
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DMLocalToGlobalBegin

updates global vectors from local vectors

Synopsis

#include "petscdm.h"          
#include "petscdmlabel.h"     
#include "petscds.h"     
PetscErrorCode  DMLocalToGlobalBegin(DM dm,Vec l,InsertMode mode,Vec g)
Neighbor-wise Collective on DM

Input Parameters

dm - the DM object
l - the local vector
mode - if INSERT_VALUES then no parallel communication is used, if ADD_VALUES then all ghost points from the same base point accumulate into that base point.
g - the global vector

Notes: In the ADD_VALUES case you normally would zero the receiving vector before beginning this operation. INSERT_VALUES is not supported for DMDA, in that case simply compute the values directly into a global vector instead of a local one.

See Also

DMCoarsen(), DMDestroy(), DMView(), DMCreateGlobalVector(), DMCreateInterpolation(), DMGlobalToLocalEnd(), DMGlobalToLocalBegin()

Level:beginner
Location:
src/dm/interface/dm.c
Index of all DM routines
Table of Contents for all manual pages
Index of all manual pages

Examples

src/dm/examples/tutorials/ex1.c.html
src/dm/examples/tutorials/ex5.c.html
src/dm/examples/tutorials/ex7.c.html
src/dm/examples/tutorials/ex9.c.html
src/ksp/ksp/examples/tutorials/ex31.c.html
src/ksp/ksp/examples/tutorials/ex42.c.html
src/ksp/ksp/examples/tutorials/ex43.c.html
src/ksp/ksp/examples/tutorials/ex49.c.html
src/ksp/ksp/examples/tutorials/ex69.c.html
src/snes/examples/tutorials/ex5.c.html
src/snes/examples/tutorials/ex15.c.html