Los Alamos Bets on ENIAC: The First Monte Carlo Simulation and the Birth of Modern Code
Los Alamos bets on ENIAC: Nuclear Monte Carlo simulations, 1947–1948 (2014) [pdf]
In 1948, a team including John and Klara von Neumann and Nick Metropolis ran a Monte Carlo simulation on ENIAC for Los Alamos. It was the first computerized Monte Carlo calculation and the first program written in the modern code paradigm—with conditional jumps and address modification—to be executed. Drawing on original flow diagrams, code versions, and the ENIAC logbook, the authors reconstruct this groundbreaking program and its role in early nuclear weapons design.
Most of the physics at Los Alamos could be reduced to the study of assemblies of particles interacting with each other, hitting each other, scattering, sometimes giving rise to new particles.