# Mathematical Digest

### Short Summaries of Articles about Mathematics

in the Popular Press

"Optimal paths to atomic clusters," by Ivars Peterson. *Science News,* 16 October 1999, page 255.

A standard problem in applied mathematics is to find the global minimum in a complex geometric landscape, which might represent, for example, the energy of interactions among a large number of atoms. Most algorithms minimize by following along a single path, thereby risking a fall into a valley that is not the desired minimum. Recently, Robert H. Leary at the San Diego Supercomputer Center devised an algorithm that was inspired by the Japanese game pachinko, in which many balls are sent with the goal of falling into a desired slot. Leary's procedure uses paths that check the results of many trial leaps from a given location. With enough trials, at least one will drop to the bottom.

*--- Benjamin Stein*