Commentz-Walter algorithm - Revision history

JCW-CleanerBot: /* Time Complexity */ task, replaced: journal=International Journal of Advanced Computer Science and Information Technology (IJACSIT) → journal=International Journal of Advanced Computer Science and Information Techno

2025-03-11T05:19:16Z

Time Complexity: task, replaced: journal=International Journal of Advanced Computer Science and Information Technology (IJACSIT) → journal=International Journal of Advanced Computer Science and Information Techno

← Previous revision		Revision as of 05:19, 11 March 2025
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	\| title=Analysis of Multiple String Pattern Matching Algorithms		\| title=Analysis of Multiple String Pattern Matching Algorithms
	\| author=Akinul Islam Jony		\| author=Akinul Islam Jony
	\| journal=International Journal of Advanced Computer Science and Information Technology ~~(IJACSIT)~~		\| journal=International Journal of Advanced Computer Science and Information Technology
	\| volume=3		\| volume=3
	\| issue=4		\| issue=4

Astraujums: Changed pronoun from "he" to "she" because Beate Commentz-Walter is a woman.

2024-01-25T08:09:50Z

Changed pronoun from "he" to "she" because Beate Commentz-Walter is a woman.

← Previous revision		Revision as of 08:09, 25 January 2024
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	== History ==		== History ==
	The paper on the algorithm was first published by [[Beate Commentz-Walter]] in 1979 through the Saarland University and typed by "R. Scherner".<ref name="albsig"/> The paper detailed two differing algorithms he claimed combined the idea of the [[Aho–Corasick algorithm\|Aho-Corasick]] and [[Boyer–Moore string-search algorithm\|Boyer-Moore]] algorithms, which he called algorithms B and B1. The paper mostly focuses on algorithm B, however.		The paper on the algorithm was first published by [[Beate Commentz-Walter]] in 1979 through the Saarland University and typed by "R. Scherner".<ref name="albsig"/> The paper detailed two differing algorithms she claimed combined the idea of the [[Aho–Corasick algorithm\|Aho-Corasick]] and [[Boyer–Moore string-search algorithm\|Boyer-Moore]] algorithms, which she called algorithms B and B1. The paper mostly focuses on algorithm B, however.

	== How the Algorithm Works ==		== How the Algorithm Works ==

204.75.143.6: removed unneeded comma

2023-06-14T16:23:29Z

removed unneeded comma

← Previous revision		Revision as of 16:23, 14 June 2023
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	== Time Complexity ==		== Time Complexity ==
	Comparing the [[Aho–Corasick algorithm\|Aho-Corasick]] to the Commentz-Walter Algorithm yields results with the idea of time complexity. [[Aho–Corasick algorithm\|Aho-Corasick]] is considered linear [[Big-O notation\|O]](''m+n+k'') where k is the number of matches. Commentz-Walter may be considered quadratic [[Big-O notation\|O]](''mn''). The reason for this, lies in the fact that Commentz-Walter was developed by adding the shifts within the [[Boyer–Moore string-search algorithm]] to the [[Aho–Corasick algorithm\|Aho-Corasick]], thus moving its complexity from linear to quadratic.		Comparing the [[Aho–Corasick algorithm\|Aho-Corasick]] to the Commentz-Walter Algorithm yields results with the idea of time complexity. [[Aho–Corasick algorithm\|Aho-Corasick]] is considered linear [[Big-O notation\|O]](''m+n+k'') where k is the number of matches. Commentz-Walter may be considered quadratic [[Big-O notation\|O]](''mn''). The reason for this lies in the fact that Commentz-Walter was developed by adding the shifts within the [[Boyer–Moore string-search algorithm]] to the [[Aho–Corasick algorithm\|Aho-Corasick]], thus moving its complexity from linear to quadratic.

	According to a study done in “The Journal of National Science Foundation of Sri Lanka 46” Commentz-Walter seems to be generally faster than the [[Aho–Corasick string matching algorithm]]. This, according to the journal, only exists when using long patterns. However, the journal does state that there is no critical analysis on this statement and that there is a lack of general agreement on the performance of the algorithm.<ref>{{cite journal		According to a study done in “The Journal of National Science Foundation of Sri Lanka 46” Commentz-Walter seems to be generally faster than the [[Aho–Corasick string matching algorithm]]. This, according to the journal, only exists when using long patterns. However, the journal does state that there is no critical analysis on this statement and that there is a lack of general agreement on the performance of the algorithm.<ref>{{cite journal

Lol1VNIO: dash, replaced: Boyer–Moore string search algorithm → Boyer–Moore string-search algorithm (2)

2023-01-30T14:51:24Z

dash, replaced: Boyer–Moore string search algorithm → Boyer–Moore string-search algorithm (2)

← Previous revision		Revision as of 14:51, 30 January 2023
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	\| publisher = Springer		\| publisher = Springer
	\| doi = 10.1007/3-540-09510-1_10		\| doi = 10.1007/3-540-09510-1_10
	\| isbn = 3-540-09510-1 }}</ref> Like the [[Aho–Corasick string matching algorithm]], it can search for multiple patterns at once. It combines ideas from Aho–Corasick with the fast matching of the [[Boyer–Moore string search algorithm]]. For a text of length ''n'' and maximum pattern length of ''m'', its worst-case running time is [[Big-O notation\|O]](''mn''), though the average case is often much better.<ref>{{cite book		\| isbn = 3-540-09510-1 }}</ref> Like the [[Aho–Corasick string matching algorithm]], it can search for multiple patterns at once. It combines ideas from Aho–Corasick with the fast matching of the [[Boyer–Moore string-search algorithm]]. For a text of length ''n'' and maximum pattern length of ''m'', its worst-case running time is [[Big-O notation\|O]](''mn''), though the average case is often much better.<ref>{{cite book
	\| title=Taxonomies and toolkits of regular language algorithms		\| title=Taxonomies and toolkits of regular language algorithms
	\| first=Bruce William		\| first=Bruce William
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	== Time Complexity ==		== Time Complexity ==
	Comparing the [[Aho–Corasick algorithm\|Aho-Corasick]] to the Commentz-Walter Algorithm yields results with the idea of time complexity. [[Aho–Corasick algorithm\|Aho-Corasick]] is considered linear [[Big-O notation\|O]](''m+n+k'') where k is the number of matches. Commentz-Walter may be considered quadratic [[Big-O notation\|O]](''mn''). The reason for this, lies in the fact that Commentz-Walter was developed by adding the shifts within the [[Boyer–Moore string search algorithm]] to the [[Aho–Corasick algorithm\|Aho-Corasick]], thus moving its complexity from linear to quadratic.		Comparing the [[Aho–Corasick algorithm\|Aho-Corasick]] to the Commentz-Walter Algorithm yields results with the idea of time complexity. [[Aho–Corasick algorithm\|Aho-Corasick]] is considered linear [[Big-O notation\|O]](''m+n+k'') where k is the number of matches. Commentz-Walter may be considered quadratic [[Big-O notation\|O]](''mn''). The reason for this, lies in the fact that Commentz-Walter was developed by adding the shifts within the [[Boyer–Moore string-search algorithm]] to the [[Aho–Corasick algorithm\|Aho-Corasick]], thus moving its complexity from linear to quadratic.

	According to a study done in “The Journal of National Science Foundation of Sri Lanka 46” Commentz-Walter seems to be generally faster than the [[Aho–Corasick string matching algorithm]]. This, according to the journal, only exists when using long patterns. However, the journal does state that there is no critical analysis on this statement and that there is a lack of general agreement on the performance of the algorithm.<ref>{{cite journal		According to a study done in “The Journal of National Science Foundation of Sri Lanka 46” Commentz-Walter seems to be generally faster than the [[Aho–Corasick string matching algorithm]]. This, according to the journal, only exists when using long patterns. However, the journal does state that there is no critical analysis on this statement and that there is a lack of general agreement on the performance of the algorithm.<ref>{{cite journal
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	\| issue=4		\| issue=4
	\| year=2014		\| year=2014
	\| pages=~~344-353~~		\| pages=344–353
	\| issn=2296-1739		\| issn=2296-1739
	\| url=https://elvedit.com/journals/IJACSIT/wp-content/uploads/2014/09/IJACSIT-3402-AoMSPMA.pdf}}</ref>		\| url=https://elvedit.com/journals/IJACSIT/wp-content/uploads/2014/09/IJACSIT-3402-AoMSPMA.pdf}}</ref>

OAbot: Open access bot: doi added to citation with #oabot.

2023-01-30T09:02:39Z

Open access bot: doi added to citation with #oabot.

← Previous revision		Revision as of 09:02, 30 January 2023
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	\| issue=4		\| issue=4
	\| pages=547–557		\| pages=547–557
	\| doi=10.4038/jnsfsr.v46i4.8630}}</ref>		\| doi=10.4038/jnsfsr.v46i4.8630\| doi-access=free
			}}</ref>

	As seen in a visualization of the algorithm’s running time done in a study by “The International Journal of Advanced Computer Science and Information Technology” the performance of the algorithm increased linearly as the shortest pattern within the pattern set increased.<ref name="IJACSIT">{{cite journal		As seen in a visualization of the algorithm’s running time done in a study by “The International Journal of Advanced Computer Science and Information Technology” the performance of the algorithm increased linearly as the shortest pattern within the pattern set increased.<ref name="IJACSIT">{{cite journal

Michael.lill: /* Time Complexity */

2022-10-19T13:44:37Z

Time Complexity

← Previous revision		Revision as of 13:44, 19 October 2022
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	== Time Complexity ==		== Time Complexity ==
	Comparing the [[Aho–Corasick algorithm\|Aho-Corasick]] to the Commentz-Walter Algorithm yields results with the idea of time complexity. ~~While~~ [[Aho–Corasick algorithm\|Aho-Corasick]] is considered linear [[Big-O notation\|O]](''n+k''), Commentz-Walter may be considered quadratic [[Big-O notation\|O]](''mn''). The reason for this, lies in the fact that Commentz-Walter was developed by adding the shifts within the [[Boyer–Moore string search algorithm]] to the [[Aho–Corasick algorithm\|Aho-Corasick]], thus moving its complexity from linear to quadratic.		Comparing the [[Aho–Corasick algorithm\|Aho-Corasick]] to the Commentz-Walter Algorithm yields results with the idea of time complexity. [[Aho–Corasick algorithm\|Aho-Corasick]] is considered linear [[Big-O notation\|O]](''m+n+k'') where k is the number of matches. Commentz-Walter may be considered quadratic [[Big-O notation\|O]](''mn''). The reason for this, lies in the fact that Commentz-Walter was developed by adding the shifts within the [[Boyer–Moore string search algorithm]] to the [[Aho–Corasick algorithm\|Aho-Corasick]], thus moving its complexity from linear to quadratic.

	According to a study done in “The Journal of National Science Foundation of Sri Lanka 46” Commentz-Walter seems to be generally faster than the [[Aho–Corasick string matching algorithm]]. This, according to the journal, only exists when using long patterns. However, the journal does state that there is no critical analysis on this statement and that there is a lack of general agreement on the performance of the algorithm.<ref>{{cite journal		According to a study done in “The Journal of National Science Foundation of Sri Lanka 46” Commentz-Walter seems to be generally faster than the [[Aho–Corasick string matching algorithm]]. This, according to the journal, only exists when using long patterns. However, the journal does state that there is no critical analysis on this statement and that there is a lack of general agreement on the performance of the algorithm.<ref>{{cite journal

怪文書: Fix typo

2022-09-22T04:52:44Z

Fix typo

← Previous revision		Revision as of 04:52, 22 September 2022
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	== How the Algorithm Works ==		== How the Algorithm Works ==
	[[File:Diagram_for_Commentz-Walter_Algorithm.png\|thumb\|385x385px\|A sample Reversed Pattern Tree]]		[[File:Diagram_for_Commentz-Walter_Algorithm.png\|thumb\|385x385px\|A sample Reversed Pattern Tree]]
	The Commentz-Walter algorithm combines two known algorithms in order to attempt to better address the multi-pattern matching problem. These two algorithms are the [[Boyer–Moore string-search algorithm\|Boyer-Moore]], which addresses single pattern matching using filtering, and the [[Aho–Corasick algorithm\|Aho-Corasick]]. To do this, the algorithm implements a suffix ~~automation~~ to search through patterns within an input string, while also using reverse patterns, unlike in the [[Aho–Corasick algorithm\|Aho-Corasick]].<ref name="IJACSIT"/>		The Commentz-Walter algorithm combines two known algorithms in order to attempt to better address the multi-pattern matching problem. These two algorithms are the [[Boyer–Moore string-search algorithm\|Boyer-Moore]], which addresses single pattern matching using filtering, and the [[Aho–Corasick algorithm\|Aho-Corasick]]. To do this, the algorithm implements a suffix automaton to search through patterns within an input string, while also using reverse patterns, unlike in the [[Aho–Corasick algorithm\|Aho-Corasick]].<ref name="IJACSIT"/>

	Commentz-Walter has two phases it must go through, these being a pre-computing phase and a matching phase. For the first phase, the Commentz-Walter algorithm uses a reversed pattern to build a pattern tree, this is considered the pre-computing phase. The second phase, known as the matching phase, takes into account the other two algorithms. Using the [[Boyer–Moore string-search algorithm\|Boyer-Moore]]’s technique of shifting and the [[Aho–Corasick algorithm\|Aho-Corasick]]'s technique of finite automata, the Commentz-Walter algorithm can begin matching.<ref name="IJACSIT"/>		Commentz-Walter has two phases it must go through, these being a pre-computing phase and a matching phase. For the first phase, the Commentz-Walter algorithm uses a reversed pattern to build a pattern tree, this is considered the pre-computing phase. The second phase, known as the matching phase, takes into account the other two algorithms. Using the [[Boyer–Moore string-search algorithm\|Boyer-Moore]]’s technique of shifting and the [[Aho–Corasick algorithm\|Aho-Corasick]]'s technique of finite automata, the Commentz-Walter algorithm can begin matching.<ref name="IJACSIT"/>

Evilninja: citation templates used (say no to link rot!); random chapter link removed; duplicate ref removed

2022-05-15T17:03:32Z

citation templates used (say no to link rot!); random chapter link removed; duplicate ref removed

← Previous revision		Revision as of 17:03, 15 May 2022
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	In [[computer science]], the '''Commentz-Walter algorithm''' is a [[string searching algorithm]] invented by [[Beate Commentz-Walter]].<ref name=":0">{{cite conference		In [[computer science]], the '''Commentz-Walter algorithm''' is a [[string searching algorithm]] invented by [[Beate Commentz-Walter]].<ref name="albsig">{{cite conference
	\| last = Commentz-Walter		\| last = Commentz-Walter
	\| first = Beate		\| first = Beate
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	\| isbn=90-386-0396-7}}</ref>		\| isbn=90-386-0396-7}}</ref>

	[[GNU]] [[grep]] ~~implements~~ a string matching algorithm very similar to Commentz-Walter.<ref>{{cite web		[[GNU]] [[grep]] once implemented a string matching algorithm very similar to Commentz-Walter.<ref>{{cite web
	\| url=https://git.savannah.gnu.org/cgit/grep.git/~~tree~~/src/kwset.c		\| url=https://git.savannah.gnu.org/cgit/grep.git/commit/src/kwset.c?id=57d32889c95e04a0f0237ec09538b22aa39fe908
			\| title=grep: remove Commentz-Walter code
	\| title=src/kwset.c: search for any of a set of keywords.
	\| date=~~August 1989~~		\| date=2017-01-18
	\| work=[[GNU]] [[grep]]		\| work=[[GNU]] [[grep]]
	\| access-date=~~2020~~-07-14}}</ref>		\| access-date=2022-05-15}}</ref>

	== History ==		== History ==
	The paper on the algorithm was first published by [[Beate Commentz-Walter]] in 1979 through the Saarland University and typed by "R. Scherner".<ref~~>{{Cite~~ journal \|last=Commentz-Walter \|first=Beate \|date=January 1980 \|title=A string matching algorithm fast on the average, TR 79.09.007 \|url=http://dx.doi.org/10.1016/0306-4379(80)90028-9 \|journal=Information Systems \|volume=5 \|issue=3 \|pages=245–246 \|doi=10.1016/0306-4379(80)90028-9 \|issn=~~0306-4379}}<~~/~~ref~~> The paper detailed two differing algorithms he claimed combined the idea of the [[Aho–Corasick algorithm\|Aho-Corasick]] and [[Boyer–Moore string-search algorithm\|Boyer-Moore]] algorithms, which he called algorithms B and B1. The paper mostly focuses on algorithm B, however.		The paper on the algorithm was first published by [[Beate Commentz-Walter]] in 1979 through the Saarland University and typed by "R. Scherner".<ref name="albsig"/> The paper detailed two differing algorithms he claimed combined the idea of the [[Aho–Corasick algorithm\|Aho-Corasick]] and [[Boyer–Moore string-search algorithm\|Boyer-Moore]] algorithms, which he called algorithms B and B1. The paper mostly focuses on algorithm B, however.

	== How the Algorithm Works ==		== How the Algorithm Works ==
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	Comparing the [[Aho–Corasick algorithm\|Aho-Corasick]] to the Commentz-Walter Algorithm yields results with the idea of time complexity. While [[Aho–Corasick algorithm\|Aho-Corasick]] is considered linear [[Big-O notation\|O]](''n+k''), Commentz-Walter may be considered quadratic [[Big-O notation\|O]](''mn''). The reason for this, lies in the fact that Commentz-Walter was developed by adding the shifts within the [[Boyer–Moore string search algorithm]] to the [[Aho–Corasick algorithm\|Aho-Corasick]], thus moving its complexity from linear to quadratic.		Comparing the [[Aho–Corasick algorithm\|Aho-Corasick]] to the Commentz-Walter Algorithm yields results with the idea of time complexity. While [[Aho–Corasick algorithm\|Aho-Corasick]] is considered linear [[Big-O notation\|O]](''n+k''), Commentz-Walter may be considered quadratic [[Big-O notation\|O]](''mn''). The reason for this, lies in the fact that Commentz-Walter was developed by adding the shifts within the [[Boyer–Moore string search algorithm]] to the [[Aho–Corasick algorithm\|Aho-Corasick]], thus moving its complexity from linear to quadratic.

	According to a study done in “The Journal of National Science Foundation of Sri Lanka 46” Commentz-Walter seems to be generally faster than the [[Aho–Corasick string matching algorithm]]. This, according to the journal, only exists when using long patterns. However, the journal does state that there is no critical analysis on this statement and that there is a lack of general agreement on the performance of the algorithm.<ref>~~Dewasurendra,~~ ~~S. and Vidanagamachchi, S., 2018.~~ Average time complexity analysis of Commentz-Walter algorithm~~. Journal of the National Science Foundation of Sri Lanka, 46(4), pp.547–557. DOI: http://doi.org/10.4038/jnsfsr.v46i4.8630</ref>~~		According to a study done in “The Journal of National Science Foundation of Sri Lanka 46” Commentz-Walter seems to be generally faster than the [[Aho–Corasick string matching algorithm]]. This, according to the journal, only exists when using long patterns. However, the journal does state that there is no critical analysis on this statement and that there is a lack of general agreement on the performance of the algorithm.<ref>{{cite journal
			\| title=Average time complexity analysis of Commentz-Walter algorithm
			\| first1=SD
			\| last1=Dewasurendra
			\| first2=SM
			\| last2=Vidanagamachchi
			\| year=2018
			\| journal=Journal of the National Science Foundation of Sri Lanka
			\| volume=46
			\| issue=4
			\| pages=547–557
			\| doi=10.4038/jnsfsr.v46i4.8630}}</ref>

	As seen in a visualization of the algorithm’s running time done in a study by “The International Journal of Advanced Computer Science and Information Technology” the performance of the algorithm increased linearly as the shortest pattern within the pattern set increased.<ref name="IJACSIT">{{cite journal		As seen in a visualization of the algorithm’s running time done in a study by “The International Journal of Advanced Computer Science and Information Technology” the performance of the algorithm increased linearly as the shortest pattern within the pattern set increased.<ref name="IJACSIT">{{cite journal
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	In the original Commentz-Walter paper, an alternative algorithm was also created. This algorithm, known as B1, operates similarly to the main Commentz-Walter algorithm with the only difference being in the way the pattern tree is used during the scanning phase.		In the original Commentz-Walter paper, an alternative algorithm was also created. This algorithm, known as B1, operates similarly to the main Commentz-Walter algorithm with the only difference being in the way the pattern tree is used during the scanning phase.

	The paper also claims this algorithm performs better at the cost of increasing the running time and space of both the preprocessing phase and search phase. This algorithm has not been formally tested in other studies however, so its actual performance is unknown.<ref name=":0" />		The paper also claims this algorithm performs better at the cost of increasing the running time and space of both the preprocessing phase and search phase. This algorithm has not been formally tested in other studies however, so its actual performance is unknown.<ref name="albsig" />

	== References ==		== References ==
	{{Reflist}}		{{Reflist}}

	== External links ==
	* {{cite book\|chapter-url=https://www.researchgate.net/figure/Example-for-Commentz-Walter-algorithm-24_fig4_314202032\|chapter=Performance of Multiple String Matching Algorithms in Text Mining\|date=March 2017\|doi=10.1007/978-981-10-3156-4_71\|title=Proceedings of the 5th International Conference on Frontiers in Intelligent Computing: Theory and Applications\|series=Advances in Intelligent Systems and Computing\|last1=Sheshasaayee\|first1=Ananthi\|last2=Thailambal\|first2=G.\|volume=516\|pages=671–681\|isbn=978-981-10-3155-7}}

	{{strings}}		{{strings}}

Evilninja: refs consolidated

2022-05-15T06:59:20Z

refs consolidated

← Previous revision		Revision as of 06:59, 15 May 2022
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	== How the Algorithm Works ==		== How the Algorithm Works ==
	[[File:Diagram_for_Commentz-Walter_Algorithm.png\|thumb\|385x385px\|A sample Reversed Pattern Tree]]		[[File:Diagram_for_Commentz-Walter_Algorithm.png\|thumb\|385x385px\|A sample Reversed Pattern Tree]]
	The Commentz-Walter algorithm combines two known algorithms in order to attempt to better address the multi-pattern matching problem. These two algorithms are the [[Boyer–Moore string-search algorithm\|Boyer-Moore]], which addresses single pattern matching using filtering, and the [[Aho–Corasick algorithm\|Aho-Corasick]]. To do this, the algorithm implements a suffix automation to search through patterns within an input string, while also using reverse patterns, unlike in the [[Aho–Corasick algorithm\|Aho-Corasick]].<ref~~>Jony,~~ ~~Akinul Islam. “Analysis of Multiple String Pattern Matching Algorithms.” International Journal of Advanced Computer Science and Information Technology (~~IJACSIT~~), vol. 3, no. 4, 2014, pp. 344–353., https://elvedit.com/journals/IJACSIT/wp-content/uploads/2014/09/IJACSIT-3402-AoMSPMA.pdf. Accessed 4 May 2022.<~~/~~ref~~>		The Commentz-Walter algorithm combines two known algorithms in order to attempt to better address the multi-pattern matching problem. These two algorithms are the [[Boyer–Moore string-search algorithm\|Boyer-Moore]], which addresses single pattern matching using filtering, and the [[Aho–Corasick algorithm\|Aho-Corasick]]. To do this, the algorithm implements a suffix automation to search through patterns within an input string, while also using reverse patterns, unlike in the [[Aho–Corasick algorithm\|Aho-Corasick]].<ref name="IJACSIT"/>

	Commentz-Walter has two phases it must go through, these being a pre-computing phase and a matching phase. For the first phase, the Commentz-Walter algorithm uses a reversed pattern to build a pattern tree, this is considered the pre-computing phase. The second phase, known as the matching phase, takes into account the other two algorithms. Using the [[Boyer–Moore string-search algorithm\|Boyer-Moore]]’s technique of shifting and the [[Aho–Corasick algorithm\|Aho-Corasick]]'s technique of finite automata, the Commentz-Walter algorithm can begin matching.<ref~~>Jony,~~ ~~Akinul Islam. “Analysis of Multiple String Pattern Matching Algorithms.” International Journal of Advanced Computer Science and Information Technology (~~IJACSIT~~), vol. 3, no. 4, 2014, pp. 346–347., https://elvedit.com/journals/IJACSIT/wp-content/uploads/2014/09/IJACSIT-3402-AoMSPMA.pdf. Accessed 4 May 2022.<~~/~~ref~~>		Commentz-Walter has two phases it must go through, these being a pre-computing phase and a matching phase. For the first phase, the Commentz-Walter algorithm uses a reversed pattern to build a pattern tree, this is considered the pre-computing phase. The second phase, known as the matching phase, takes into account the other two algorithms. Using the [[Boyer–Moore string-search algorithm\|Boyer-Moore]]’s technique of shifting and the [[Aho–Corasick algorithm\|Aho-Corasick]]'s technique of finite automata, the Commentz-Walter algorithm can begin matching.<ref name="IJACSIT"/>

	The Commentz-Walter algorithm will scan backwards throughout an input string, checking for a mismatch. If and when the algorithm does find a mismatch, the algorithm will already know some of the characters that are matches, and then use this information as an index. Using the index, the algorithm checks the pre-computed table to find a distance that it must shift, after this, the algorithm once more begins another matching attempt.		The Commentz-Walter algorithm will scan backwards throughout an input string, checking for a mismatch. If and when the algorithm does find a mismatch, the algorithm will already know some of the characters that are matches, and then use this information as an index. Using the index, the algorithm checks the pre-computed table to find a distance that it must shift, after this, the algorithm once more begins another matching attempt.
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	According to a study done in “The Journal of National Science Foundation of Sri Lanka 46” Commentz-Walter seems to be generally faster than the [[Aho–Corasick string matching algorithm]]. This, according to the journal, only exists when using long patterns. However, the journal does state that there is no critical analysis on this statement and that there is a lack of general agreement on the performance of the algorithm.<ref>Dewasurendra, S. and Vidanagamachchi, S., 2018. Average time complexity analysis of Commentz-Walter algorithm. Journal of the National Science Foundation of Sri Lanka, 46(4), pp.547–557. DOI: http://doi.org/10.4038/jnsfsr.v46i4.8630</ref>		According to a study done in “The Journal of National Science Foundation of Sri Lanka 46” Commentz-Walter seems to be generally faster than the [[Aho–Corasick string matching algorithm]]. This, according to the journal, only exists when using long patterns. However, the journal does state that there is no critical analysis on this statement and that there is a lack of general agreement on the performance of the algorithm.<ref>Dewasurendra, S. and Vidanagamachchi, S., 2018. Average time complexity analysis of Commentz-Walter algorithm. Journal of the National Science Foundation of Sri Lanka, 46(4), pp.547–557. DOI: http://doi.org/10.4038/jnsfsr.v46i4.8630</ref>

	As seen in a visualization of the algorithm’s running time done in a study by “The International Journal of Advanced Computer Science and Information Technology” the performance of the algorithm increased linearly as the shortest pattern within the pattern set increased.<ref>{{cite journal		As seen in a visualization of the algorithm’s running time done in a study by “The International Journal of Advanced Computer Science and Information Technology” the performance of the algorithm increased linearly as the shortest pattern within the pattern set increased.<ref name="IJACSIT">{{cite journal
	\| title=Analysis of Multiple String Pattern Matching Algorithms		\| title=Analysis of Multiple String Pattern Matching Algorithms
	\| author=Akinul Islam Jony		\| author=Akinul Islam Jony

Evilninja: cite web used (say no to link rot!)

2022-05-15T06:57:34Z

cite web used (say no to link rot!)

← Previous revision		Revision as of 06:57, 15 May 2022
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	According to a study done in “The Journal of National Science Foundation of Sri Lanka 46” Commentz-Walter seems to be generally faster than the [[Aho–Corasick string matching algorithm]]. This, according to the journal, only exists when using long patterns. However, the journal does state that there is no critical analysis on this statement and that there is a lack of general agreement on the performance of the algorithm.<ref>Dewasurendra, S. and Vidanagamachchi, S., 2018. Average time complexity analysis of Commentz-Walter algorithm. Journal of the National Science Foundation of Sri Lanka, 46(4), pp.547–557. DOI: http://doi.org/10.4038/jnsfsr.v46i4.8630</ref>		According to a study done in “The Journal of National Science Foundation of Sri Lanka 46” Commentz-Walter seems to be generally faster than the [[Aho–Corasick string matching algorithm]]. This, according to the journal, only exists when using long patterns. However, the journal does state that there is no critical analysis on this statement and that there is a lack of general agreement on the performance of the algorithm.<ref>Dewasurendra, S. and Vidanagamachchi, S., 2018. Average time complexity analysis of Commentz-Walter algorithm. Journal of the National Science Foundation of Sri Lanka, 46(4), pp.547–557. DOI: http://doi.org/10.4038/jnsfsr.v46i4.8630</ref>

	As seen in a visualization of the algorithm’s running time done in a study by “The International Journal of Advanced Computer Science and Information Technology” the performance of the algorithm increased linearly as the shortest pattern within the pattern set increased.<ref>~~https://elvedit.com/journals/IJACSIT/wp-content/uploads/2014/09/IJACSIT-3402-AoMSPMA.pdf~~ {{~~Bare URL PDF\|date=May~~ ~~2022}}</ref>~~		As seen in a visualization of the algorithm’s running time done in a study by “The International Journal of Advanced Computer Science and Information Technology” the performance of the algorithm increased linearly as the shortest pattern within the pattern set increased.<ref>{{cite journal
			\| title=Analysis of Multiple String Pattern Matching Algorithms
			\| author=Akinul Islam Jony
			\| journal=International Journal of Advanced Computer Science and Information Technology (IJACSIT)
			\| volume=3
			\| issue=4
			\| year=2014
			\| pages=344-353
			\| issn=2296-1739
			\| url=https://elvedit.com/journals/IJACSIT/wp-content/uploads/2014/09/IJACSIT-3402-AoMSPMA.pdf}}</ref>

	== Alternative Algorithm ==		== Alternative Algorithm ==