A genetic algorithm based method for form evaluation of a circle is proposed. Firstly

after an introduction to the background of the form error evaluation method and that of the genetic algorithm

a mathematical model of circularity error together with a fitness (evaluation) function is given in terms of the Mathematical Definition of Dimensional and Tolerancing Principles

which corresponds to the minimum zone definition and is easy for interpretation and computer implementation. Then

with the least square solution as the initial value

the whole implementation process of the genetic algorithm in the circularity evaluation is dwelt on. Finally

the simulation results of a quoted example are analyzed and a brief conclusion is given. The example simulation indicates that genetic optimization algorithm has such distinctive advantages as solving nonlinear and large space problems

converging to global optimum solution and convenience of implementation

etc.

and it is quite suitable for the form error assessment.