call Grid_getBlkIDFromPos(real(IN) :: pos(:), integer(OUT) :: ansBlockID, integer(OUT) :: ansProcID, optional,integer(IN) :: comm)
Returns the processor and blkID containing the cell that overlaps with the specified position co-ordinate
pos :: co-ordinates of the point ansBlockID :: the local blockID of the block that contains the point ansProcID :: the processor ID that contains the point comm :: if communication is necessary, a communicator must be specified here. Communication is necessary unless the setup uses BITTREE. The comm argument is ignored if BITTREE is used.
If a communicator comm is present and used, then this routine must be called collectively by all MPI tasks in the communicator.