Rmpi (version 0.7-2)

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)

Value

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

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)

Author

Alek Hunchak and Hao Yu

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

https://www.open-mpi.org/

See Also

mpi.cart.create,mpi.proc.null

Examples

# \donttest{
#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))
# }