Editing Genetic operator (section)

{{distinguish|Operator (genetics)}}
{{Evolutionary algorithms}}
A '''genetic operator''' is an [[Operator (programming)|operator]] used in [[evolutionary algorithms]] (EA) to guide the algorithm towards a solution to a given problem. There are three main types of operators ([[Mutation (evolutionary algorithm) |mutation]], [[Crossover (evolutionary algorithm)|crossover]] and [[selection (evolutionary algorithm)|selection]]), which must work in conjunction with one another in order for the algorithm to be successful.<ref>{{cite journal |last1=Jiang |first1=Dazhi |last2=Tian |first2=Zhihang |last3=He |first3=Zhihui |last4=Tu |first4=Geng |last5=Huang |first5=Ruixiang |title=A framework for designing of genetic operators automatically based on gene expression programming and differential evolution |journal=Natural Computing |date=1 September 2021 |volume=20 |issue=3 |pages=395–411 |doi=10.1007/s11047-020-09830-2 |url=https://link.springer.com/article/10.1007/s11047-020-09830-2 |language=en |issn=1572-9796|url-access=subscription }}</ref> Genetic operators are used to create and maintain [[genetic diversity]] (mutation operator), combine existing solutions (also known as [[chromosome (evolutionary algorithm)|chromosome]]s) into new solutions (crossover) and select between solutions (selection).<ref name=ga-intro>{{cite web|title=Introduction to Genetic Algorithms|url=http://www.doc.ic.ac.uk/~nd/surprise_96/journal/vol1/hmw/article1.html|accessdate=20 August 2015|archive-url=https://web.archive.org/web/20150811025830/http://www.doc.ic.ac.uk/~nd/surprise_96/journal/vol1/hmw/article1.html|archive-date=11 August 2015|url-status=dead}}</ref><ref name=":0" /> 

The classic representatives of evolutionary algorithms include [[Genetic algorithm|genetic algorithms]], [[Evolution strategy|evolution strategies]], [[genetic programming]] and [[evolutionary programming]]. In his book discussing the use of genetic programming for the optimization of complex problems, computer scientist [[John Koza]] has also identified an 'inversion' or 'permutation' operator; however, the effectiveness of this operator has never been conclusively demonstrated and this operator is rarely discussed in the field of genetic programming.<ref name="koza">{{cite book|last1=Koza|first1=John R.|title=Genetic programming : on the programming of computers by means of natural selection|url=https://archive.org/details/geneticprogrammi0000koza|url-access=registration|date=1996|publisher=MIT Press|location=Cambridge, Mass.|isbn=0-262-11170-5|edition=6th}}</ref><ref name="gp-operators">{{Cite FTP |title=Genetic programming operators|url=ftp://ftp.cis.upenn.edu/pub/hollick/public_html/genetic/node7.html#SECTION00023000000000000000|server=FTP server|url-status=dead|accessdate=20 August 2015}}</ref> For [[Combinatorial optimization|combinatorial problems]], however, [[Mutation (evolutionary algorithm)#Mutation of permutations|these and other operators]] tailored to [[Permutation|permutations]] are frequently used by other EAs.<ref>{{Cite book |last1=Eiben |first1=A.E. |title=Introduction to Evolutionary Computing |last2=Smith |first2=J.E. |date=2015 |publisher=Springer |isbn=978-3-662-44873-1 |edition=2nd |series=Natural Computing Series |location=Berlin, Heidelberg |pages=69–70 |language=en |chapter=Mutation for Permutation Representation |doi=10.1007/978-3-662-44874-8}}</ref><ref>{{Cite book |last1=Yu |first1=Xinjie |title=Introduction to Evolutionary Algorithms |last2=Gen |first2=Mitsuo |date=2010 |publisher=Springer |isbn=978-1-84996-128-8 |series=Decision Engineering |volume= |location=London |pages=286–288 |chapter=Mutation Operators |doi=10.1007/978-1-84996-129-5}}</ref>

Mutation (or mutation-like) operators are said to be ''[[Unary operation|unary]]'' operators, as they only operate on one chromosome at a time. In contrast, crossover operators are said to be ''[[Binary operation|binary]]'' operators, as they operate on two chromosomes at a time, combining two existing chromosomes into one new chromosome.<ref name=ga-operators>{{cite web|title=Genetic operators|url=http://kal-el.ugr.es/GAGS/gags-tutorial/node3.html|accessdate=20 August 2015|archive-date=30 December 2017|archive-url=https://web.archive.org/web/20171230171723/http://kal-el.ugr.es/GAGS/gags-tutorial/node3.html|url-status=dead}}</ref><ref>{{Cite book |last1=Eiben |first1=A.E. |title=Introduction to Evolutionary Computing |last2=Smith |first2=J.E. |date=2015 |publisher=Springer |isbn=978-3-662-44873-1 |edition=2nd |series=Natural Computing Series |location=Berlin, Heidelberg |pages=31–33 |language=en |chapter=Variation Operators (Mutation and Recombination) |doi=10.1007/978-3-662-44874-8}}</ref>