The use of the CM-200, CM-5, Cray YMP and Cray T3D computers of Los Alamos National Laboratory, the Intel iPSC/860 computer of the University of Texas, the Ncube 2 computer of Sandia National Laboratory and the Intel Paragon computer of Cal Tech is greatly appreciated. The assistance of N. A. Berner, C. Hollabaugh, A. Kalhan, H. Kohli, A. Lorber, R. McLay, and Y. Shen is gratefully acknowledged.
This work is supported in part by ARPA through grant DABT63-92-C-0024, with the University of Texas at Austin. This work was also supported in part by the Department of Energy through grant W-7405-ENG-36, with Los Alamos National Laboratory.