The alternating segment Crank-Nicolson method has been developed for a
1-dimensional diffusion equation, as well as the alternating band and
block Crank-Nicolson methods for 2-dimensional problems. Here the alt
ernating block technique is further extended to a 3-space dimension di
ffusion equation, and the new method called alternating block Crank-Ni
colson ABkC-N method, which is suitable to MIMD computers, is set up.