Defining length
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 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.[1]
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 cross-over.
gollark: Fingernails are at least slightly useful for certain fine manipulation tasks. Toenails are not, because most people cannot move their toes very precisely, and feet are in inconvenient positions in mot cases.
gollark: Yes they are. The bottom of my feet is presumably quite calloused and is fine.
gollark: It isn't inconsistent for people to feel that whatever characteristic they have doesn't match their self-image or preference.
gollark: Just alter your voice in software.
gollark: Fire laser at your eye and toggle it on and off to display the time in binary.
References
- "Foundations of Genetic Programming". UCL UK. Retrieved 13 July 2010.
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