DMCreateInterpolation

Gets the interpolation matrix between two DM objects. The resulting matrix map degrees of freedom in the vector obtained by DMCreateGlobalVector() on the coarse DM to similar vectors on the fine grid DM.

Synopsis

#include "petscdm.h"          
#include "petscdmlabel.h"     
#include "petscds.h"     
PetscErrorCode DMCreateInterpolation(DM dmc, DM dmf, Mat *mat, Vec *vec)

Collective

Input Parameters

• dmc - the DM object

• dmf - the second, finer DM object

Output Parameters

• mat - the interpolation

• vec - the scaling (optional, pass NULL if not needed), see DMCreateInterpolationScale()

Notes

For DMDA objects this only works for “uniform refinement”, that is the refined mesh was obtained DMRefine() or the coarse mesh was obtained by DMCoarsen(). The coordinates set into the DMDA are completely ignored in computing the interpolation.

For DMDA objects you can use this interpolation (more precisely the interpolation from the DMGetCoordinateDM()) to interpolate the mesh coordinate vectors EXCEPT in the periodic case where it does not make sense since the coordinate vectors are not periodic.

See Also

DM Basics, DM, DMDestroy(), DMView(), DMCreateGlobalVector(), DMCreateColoring(), DMCreateMatrix(), DMCreateMassMatrix(), DMRefine(), DMCoarsen(), DMCreateRestriction(), DMCreateInterpolationScale()

Level

developer

Location

src/dm/interface/dm.c

Examples

src/ksp/ksp/tutorials/ex36.cxx
src/snes/tutorials/ex36.c
src/dm/impls/stag/tutorials/ex4.c
src/ksp/ksp/tutorials/ex42.c
src/dm/tutorials/ex3.c
src/snes/tutorials/ex48.c
src/ksp/ksp/tutorials/ex73.c
src/ksp/ksp/tutorials/ex65.c
src/ksp/ksp/tutorials/ex35.cxx
src/snes/tutorials/ex11.c

Implementations

DMCreateInterpolation_Composite() in src/dm/impls/composite/pack.c
DMCreateInterpolation_DA() in src/dm/impls/da/dainterp.c
DMCreateInterpolation_pforest() in src/dm/impls/forest/p4est/pforest.h
DMCreateInterpolation_Moab() in src/dm/impls/moab/dmmbmg.cxx
DMCreateInterpolation_Plex() in src/dm/impls/plex/plex.c
DMCreateInterpolation_Redundant() in src/dm/impls/redundant/dmredundant.c
DMCreateInterpolation_Stag() in src/dm/impls/stag/stag.c
DMCreateInterpolation_SNESVI() in src/snes/impls/vi/rs/virs.c

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Index of all DM routines
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Index of all manual pages