#include "petscpc.h" PetscErrorCode PCFieldSplitSetFields(PC pc,const char splitname,PetscInt n,const PetscInt *fields,const PetscInt *fields_col)Logically Collective on PC
|pc||- the preconditioner context|
|splitname||- name of this split, if NULL the number of the split is used|
|n||- the number of fields in this split|
|fields||- the fields in this split|
The PCFieldSplitSetFields() is for defining fields as strided blocks. For example, if the block size is three then one can define a field as 0, or 1 or 2 or 0,1 or 0,2 or 1,2 which mean 0xx3xx6xx9xx12 ... x1xx4xx7xx ... xx2xx5xx8xx.. 01x34x67x... 0x1x3x5x7.. x12x45x78x.... where the numbered entries indicate what is in the field.
This function is called once per split (it creates a new split each time). Solve options for this split will be available under the prefix -fieldsplit_SPLITNAME_.
Developer Note: This routine does not actually create the IS representing the split, that is delayed until PCSetUp_FieldSplit(), because information about the vector/matrix layouts may not be available when this routine is called.