Rmpi (version 0.6-9)

mpi.cart.shift: MPI\_Cart\_shift

Description

mpi.cart.shift shifts the Cartesian topology in both manners, displacement and direction.

Usage

mpi.cart.shift(comm=3, direction, disp)

Arguments

comm

Communicator with Cartesian structure

direction

Coordinate dimension of the shift

disp

displacement (>0 for upwards or left shift, <0 for downwards or right shift)

Value

mpi.cart.shift returns a vector containing information regarding the rank of the source process and rank of the destination process.

Details

mpi.cart.shift provides neighbor ranks from given direction and displacement. The direction argument indicates the dimension of the shift. direction=1 means the first dim, direction=2 means the second dim, etc. disp=1 or -1 provides immediate neighbor ranks and disp=2 or -2 provides neighbor's neighbor ranks. Negative ranks mean out of boundary. They correspond to mpi.proc.null.

References

http://www.openmpi.org/

See Also

mpi.cart.create,mpi.proc.null

Examples

# NOT RUN {
#Need at least 9 slaves
mpi.bcast.cmd(mpi.cart.create(1,c(3,3),c(F,T)))
mpi.cart.create(1,c(3,3),c(F,T))
mpi.remote.exec(mpi.cart.shift(3,2,1))#get neighbor ranks
mpi.remote.exec(mpi.cart.shift(3,1,1))
# }