9.2 Ghost List Exchange

It is possible to exchange sparse lists of ghost elements between FEM chunks.

void FEM_Exchange_ghost_lists(int elemType,int nIdx,const int *localIdx);
SUBROUTINE FEM_Exchange_ghost_lists(elemType,nIdx,localIdx)
INTEGER, INTENT(IN) :: elemType,nIdx
INTEGER, INTENT(IN) :: localIdx[nIdx]

This routine sends the local element indices in localIdx to those neighboring chunks that connect to its ghost elements on the other side. That is, if the element localIdx[i] has a ghost on some chunk c, localIdx[i] will be sent to and show up in the ghost list of chunk c.

int FEM_Get_ghost_list_length(void);
Returns the number of entries in my ghost list--the number of my ghosts that other chunks passed to their call to FEM_Exchange_ghost_lists.

void FEM_Get_ghost_list(int *retLocalIdx);
SUBROUTINE FEM_Get_ghost_list(retLocalIdx)
INTEGER, INTENT(OUT) :: retLocalIdx[FEM_Get_ghost_list_length()]

These routines access the list of local elements sent by other chunks. The returned indices will all refer to ghost elements in my chunk.