next up previous contents
Next: 3 Regression Related Studies Up: 3 Symbolic Regression Previous: 1 Regression Functions and   Contents

2 Regression Fitness Assessment

Fitness for the Regression problem instances is determined by summing the squared difference between the target value for each $x$ value. In Chapter 5, fitness is reported as ``adjusted fitness'', where this is defined by the following equation:

\textrm{adjusted fitness} = \frac{1}{1 + \textrm{fitness}}.

S Gustafson 2004-05-20