** Next:** 3 Entropy
** Up:** 1 Diversity Measures Used
** Previous:** 1 Genotype Diversity
** Contents**

Phenotype diversity represents the number of unique
fitness values in a population.
The number of possible
fitness values is determined by the fitness function and varies between
problem domains. For example, in the Parity problem, there
is a finite number of possible fitness values that an individual can have.
Instead,
the fitness space is continuous in regression
problems, but due to
the precision of numbers, wrappers around operators (protected
division for instance) and the presence of non-functional code
it is possible for different trees to have the same fitness.

S Gustafson
2004-05-20