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: I was referring to filtering "liches and other stuff necromancers stumble upon".
gollark: *Can* they actually filter that (EDIT: referring to "liches and other stuff necromancers stumble upon") in practice, given the whole "end to end encryption" thing, apart from somehow not letting those on the network?
gollark: SCP-2167 and the other demonics stuff (http://www.scp-wiki.net/a-brief-explanation-on-demonics) probably qualifies.
gollark: Yep, a few came.
gollark: https://www.ibm.com/blogs/research/2019/10/on-quantum-supremacy/Interesting article related to the quantum supremacy thing - apparently IBM ran the same thing on classical computers in a few days, rather than the cited 10000 years.
References
- "Foundations of Genetic Programming". UCL UK. Retrieved 13 July 2010.
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