The results reported here were obtained on two computer platforms: an Apple Macintosh® 333MHz PowerBook G3 laptop (Apple Computer, Cupertino, CA), and a Digital Alpha 500/266 Workstation (Compaq computer, Houston, TX), each with 192 Mbyte of RAM. The Macintosh versions of the program were compiled under MetroWerks Code Warrior version 5, and the Digital versions were compiled under Digital UNIX 4.0.