Klára Dán von Neumann Codes the First Monte Carlo Simulations on ENIAC

Machines leveraging chance with stored programs, the roots actually extend to just after WWII with the story of Klára Dán von Neumann.

Besides how often overlooked early women programmers were, the story of Klára Dán von Neumann also reminds us (again and again) of the uncomfortable and unrelenting connection between computers and the military, including weapons as unsavory as the atomic variety.

In the spring of 1948 Klára Dán von Neumann (wife of John von Neumann) wrote and ran the code for a series of Monte Carlo simulations of nuclear chain reactions for Los Alamos on ENIAC. The machine had only just been converted to run programs stored in memory. The method, devised by Stanisław Ulam and John von Neumann with Nicholas Metropolis, answered questions too complex to calculate directly by following thousands of random paths and counting the outcomes. Her programs were among the first to use a modern, stored-program design. Chance put to work by a machine, the same principle runs through generative art from Georg Nees, Vera Molnár and onward.