The design of the MAD Design Program

The study of long term stability in particle accelerators has long been served by a group of widely circulated computer programs. The progress in these programs has mirrored the growth and versatility in accelerator size, complexity, and purpose, as well as evolving technologies in computing software and hardware. A number of large accelerator projects during the last decade were designed with the aid of physics programs either written for, or tailored for the project at hand, each invariably benefiting from contributions of previous workers. This paper outlines the recent history of of expample of an accelerator lattice model tool kit, the Methodical Accelerator Design (MAD) Program, which has tried to knit together this collective wisdom of the accelerator community, The ideas behind the software design of the program itself are traced here; the accelerator physics contents and origins are thoroughly documented elsewhere. These informal notes have a Brookhaven flavor, in part because of early BNL efforts to generalize the ways that technical problems are organized and presented to computers. Some recent BNL applications not covered in the extensive CERN documentation are also included.