Computer simulation

Lore & Background

Computer simulation developed hand-in-hand with the rapid growth of the computer, following its first large-scale deployment during the Manhattan Project in World War II to model the process of nuclear detonation. That early simulation involved 12 hard spheres using a Monte Carlo algorithm. Computer simulation is often used as an adjunct to or substitute for modeling systems for which simple closed-form analytic solutions are not possible. Simulations are realized by running computer programs that can be small and run almost instantly, or large-scale programs that run for hours or days on network-based groups of computers. The scale of events simulated has far exceeded anything possible with traditional paper-and-pencil modeling. Models used for computer simulations can be classified according to several attributes: stochastic or deterministic, steady-state or dynamic, continuous or discrete, local or distributed. A special type of discrete simulation is agent-based simulation, where individual entities are represented directly with internal states and behaviors. Distributed models run on a network of interconnected computers, often referred to as distributed simulations.

Reader's Guide

Computer simulation has become an essential tool across many fields because it allows exploration of systems too complex for analytical solutions. Its reliability can be determined by comparing results to real-world outcomes. The computational cost of simulation has led to the use of computer experiments for inference such as uncertainty quantification. The distinction between model and simulation is important: a model consists of equations, while simulation is the actual running of programs that solve those equations. Data preparation varies widely, from a few numbers to terabytes of information, and input sources include sensors, control surfaces, historical data, and outputs from other simulations. Because digital mathematics is imperfect, rounding and truncation errors multiply, making error analysis useful to confirm output accuracy. The variety of simulation systems has led to many specialized simulation languages, the best-known being Simula. The scale of simulations has grown enormously, from early nuclear detonation models to billion-atom material deformation models and whole-organism simulations, demonstrating the expanding capability and importance of computer simulation in research and development.

Did You Know?

• The first large-scale deployment of computer simulation was during the Manhattan Project in World War II, modeling nuclear detonation with 12 hard spheres using a Monte Carlo algorithm.