Design Alternatives (2)
2-D Decomposition - On a ?P????P processor grid, messages of size 2N/?P???Z to 4 neighbors, so
T = tcN2Z/P + ts4 + tw2NZ/?P
Good if ts < twNZ(2-1/?P)
3-D Decomposition - On a Px ? Py ? Pz grid,
T = tcN2Z/P + ts6 + tw2(N2/(PxPy) + (NZ)/(PxPz) +(NZ)/(PyPz) )