Editing Fuzzy Control Language

{{unref |date=April 2024}}
'''Fuzzy Control Language''', or '''FCL''', is a language for implementing [[fuzzy logic]], especially [[fuzzy control]]. It was standardized by IEC 61131-7. It is a [[domain-specific programming language]]: it has no features unrelated to fuzzy logic, so it is impossible to even print "[[Hello world program|Hello, world!]]". Therefore, one does not write a program in FCL, but one may write ''part'' of it in FCL.

== Example ==

 RULE 0: IF (temperature IS cold) THEN (output IS low)
 RULE 1: IF (temperature IS very cold) THEN (output IS high)

== Limitations ==

FCL is not an entirely complete fuzzy language, for instance, it does not support "hedges", which are adverbs that modify the set. For instance, the programmer cannot write:

RULE 0: If (Temperature is VERY COLD) then (Output is VERY HIGH)

However, the programmer can simply define new sets for "very cold" and "very high". FCL also lacks support for higher-order fuzzy sets, subsets, and so on. None of these features are essential to fuzzy control, although they may be nice to have.


==References==
{{reflist}}

==External links==
* [http://www.fuzzytech.com fuzzyTECH], a commercial fuzzy logic development system containing the specification document for IEC1131-7 (select Fuzzy Application Library)
* [http://www.fuzzytech.com/binaries/ieccd1.pdf IEC 1131-7 CD1] {{Webarchive|url=https://web.archive.org/web/20210304150537/https://www.fuzzytech.com/binaries/ieccd1.pdf |date=2021-03-04 }} IEC 1131-7 CD1 PDF
* [http://code.google.com/p/fuzzylite fuzzylite], A fuzzy logic controller library written in C++.
* [http://ffll.sourceforge.net Free Fuzzy Logic Library (FFLL)], an implementation library written in C++.
* [http://jfuzzylogic.sourceforge.net JFuzzyLogic], open source FCL + Fuzzy Logic Package (sourceforge, java)
* [http://sourceforge.net/projects/awifuzz AwiFuzz], open source implementation written in C++ covering all three levels of IEC 61131-7 Fuzzy Controller Language 
*[http://pyfuzzy.sourceforge.net/ pyfuzzy], open source implementation written in python.

[[Category:Fuzzy logic]]
[[Category:Domain-specific programming languages]]


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