petsc-3.13.6 2020-09-29
DMStagPopulateLocalToGlobalInjective
populate an internal 1-to-1 local-to-global map
Synopsis
PetscErrorCode DMStagPopulateLocalToGlobalInjective(DM dm)
Collective
Creates an internal object which explicitly maps a single local degree of
freedom to each global degree of freedom. This is used, if populated,
instead of SCATTER_REVERSE_LOCAL with the (1-to-many, in general)
global-to-local map, when DMLocalToGlobal() is called with INSERT_VALUES.
This allows usage, for example, even in the periodic, 1-rank case, where
the inverse of the global-to-local map, even when restricted to on-rank
communication, is non-injective. This is at the cost of storing an additional
VecScatter object inside each DMStag object.
Input Parameter
dm -the DMStag object
Notes
In normal usage, library users shouldn't be concerned with this function,
as it is called during DMSetUp(), when required.
Returns immediately if the internal map is already populated.
Developer Notes
This could, if desired, be moved up to a general DM routine. It would allow,
for example, DMDA to support DMLocalToGlobal() with INSERT_VALUES,
even in the single-rank periodic case.
See Also
DMSTAG, DMLocalToGlobal(), VecScatter
Level
developer
Location
src/dm/impls/stag/stagutils.c
Implementations
DMStagPopulateLocalToGlobalInjective_1d in src/dm/impls/stag/stag1d.c
DMStagPopulateLocalToGlobalInjective_2d in src/dm/impls/stag/stag2d.c
DMStagPopulateLocalToGlobalInjective_3d in src/dm/impls/stag/stag3d.c
Index of all DMSTAG routines
Table of Contents for all manual pages
Index of all manual pages