Editing Defining length

{{Technical|date=August 2011}}
{{Use dmy dates|date=July 2023}}
In [[genetic algorithms]] and [[genetic programming]] '''defining length''' L(H) is the maximum distance between two defining symbols (that is symbols that have a fixed value as opposed to symbols that can take any value, commonly denoted as # or *) in [[schema (genetic algorithms)|schema]] H. In tree GP schemata, L(H) is the number of links in the minimum tree fragment including all the non-= symbols within a schema H.<ref name="UCL1">{{cite web|title=Foundations of Genetic Programming|url=http://www.cs.ucl.ac.uk/staff/W.Langdon/FOGP/|publisher=UCL UK|accessdate=13 July 2010}}</ref>

== Example ==

Schemata "00##0", "1###1", "01###", and "##0##" have defining lengths of 4, 4, 1, and 0, respectively. Lengths are computed by determining the last fixed position and subtracting from it the first fixed position.

In [[genetic algorithms]] as the defining length of a solution increases so does the susceptibility of the solution to disruption due to [[mutation]] or [[Crossover (genetic algorithm)|cross-over]].

== References ==
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[[Category:Evolutionary algorithms]]


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