DMCreateFieldDecomposition#

Returns a list of IS objects defining a decomposition of a problem into subproblems corresponding to different fields.

Synopsis#

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

Not Collective; No Fortran Support

Input Parameter#

dm - the DM object

Output Parameters#

len - The number of fields (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#

Each IS contains the global indices of the dofs of the corresponding field, defined by DMAddField(). The optional list of DMs define the DM for each subproblem.

The same as DMCreateFieldIS() but also returns a DM for each field.

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

Developer Notes#

It is not clear why this function and DMCreateFieldIS() exist. Having two seems redundant and confusing.

Unlike DMRefine(), DMCoarsen(), and DMCreateDomainDecomposition() this provides no mechanism to provide hooks that are called after the decomposition is computed.