Separate HTML for Basic Foil 22 Cartesian Topology in MPI -- MPI_CART

Basic HTML version of Foils prepared 6 December 96

Foil 22 Cartesian Topology in MPI -- MPI_CART_SUB

From Full Matrices - December 4, 1995 CPS615 Basic Simulation Track for Computational Science -- Fall Semester 95. by Geoffrey C. Fox, Nancy J. McCracken

MPI_CART_SUB(comm2d, [F,T], comm2drows)

Uses the 2 element boolean vector to determine if the ith dim occurs in the subgrid (T for true) or not (F for false). This example returns a handle called comm2drows which will consist of

sqrt(N) non-overlapping communicators, each of which consists of sqrt(N) column elements.

Then when we call MPI_Bcast with the communicator comm2drows, the broadcast occurs within the individual row communicators.