petsc-3.10.5 2019-03-28
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# DMCreateFieldDecomposition

Returns a list of IS objects defining a decomposition of a problem into subproblems corresponding to different fields: each IS contains the global indices of the dofs of the corresponding field. The optional list of DMs define the DM for each subproblem. Generalizes DMCreateFieldIS().

### Synopsis

    #include "petscdm.h"
    #include "petscdmlabel.h"
    #include "petscds.h"
    PetscErrorCode DMCreateFieldDecomposition(DM dm, PetscInt *len, char ***namelist, IS **islist, DM **dmlist)

Not collective

### Input Parameter

dm -the DM object

### Output Parameters

| len | - The number of subproblems in the field decomposition (or NULL if not requested)
| namelist | - The name for each field (or NULL if not requested)
| islist | - The global indices for each field (or NULL if not requested)
| dmlist | - The DMs for each field subproblem (or NULL, if not requested; if NULL is returned, no DMs are defined)

### Notes

The user is responsible for freeing all requested arrays. In particular, every entry of names should be freed with PetscFree(), every entry of is should be destroyed with ISDestroy(), every entry of dm should be destroyed with DMDestroy(), and all of the arrays should be freed with PetscFree().

### See Also

DMDestroy(), DMView(), DMCreateInterpolation(), DMCreateColoring(), DMCreateMatrix(), DMCreateFieldIS()

### Level

intermediate

### Location

src/dm/interface/dm.c

### Examples

src/ksp/ksp/examples/tutorials/ex43.c.html

### Implementations

DMCreateFieldDecomposition_Composite in src/dm/impls/composite/pack.c
DMCreateFieldDecomposition_DA in src/dm/impls/da/dacreate.c
Index of all DM routines
Table of Contents for all manual pages
Index of all manual pages