Dealing with Rounding Error Problems in Evolutionary Physical Simulation

This paper introduces the problem of floating-point rounding errors in physical simulation. A simple virtual creature is simulated in a physical environment for a specified number of time steps. The effect of rounding errors is illustrated by varying the initial position of the creature which causes a change in the fitness value computed by a simple distance-based fitness function. With a large evaluation time, these rounding errors can produce significantly large differences in fitness. A discussion is provided on the importance of this finding for evolutionary simulations, including suggestions to alleviate the problem.