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(To be removed) Transform Mamdani fuzzy inference system into Sugeno fuzzy inference system

mam2sug will be removed in a future release. Use convertToSugeno instead. For more information, see Compatibility Considerations.



sugFIS = mam2sug(mamFIS) transforms a Mamdani fuzzy inference system into a Sugeno fuzzy inference system.


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Load a Mamdani fuzzy inference system.

mam_fismat = readfis('mam22.fis');

Convert this system to a Sugeno fuzzy inference system.

sug_fismat = mam2sug(mam_fismat);

Plot the output surfaces for both fuzzy systems.

title('Mamdani system (Output 1)')
title('Sugeno system (Output 1)')
title('Mamdani system (Output 2)')
title('Sugeno system (Output 2)')

The output surfaces for both systems are similar.

Input Arguments

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Mamdani fuzzy inference system, specified as a structure. Construct mamFIS at the command line or using the Fuzzy Logic Designer. For more information, see Build Fuzzy Systems at the Command Line and Build Fuzzy Systems Using Fuzzy Logic Designer.

Output Arguments

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Sugeno fuzzy inference system, returned as a structure. sugFIS:

  • Has constant output membership functions, whose values correspond to the centroids of the output membership functions in mamFIS

  • Uses the weighted-average defuzzification method

  • Uses the product implication method

  • Uses the sum aggregation method

The remaining properties of sugFIS, including the input membership functions and rule definitions remain unchanged from mamFIS.


  • If you have a functioning Mamdani fuzzy inference system, consider using mam2sug to convert to a more computationally efficient Sugeno structure to improve performance.

  • If sugFIS has a single output variable and you have appropriate measured input/output training data, you can tune the membership function parameters of sugFIS using anfis.

Version History

Introduced before R2006a

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R2019b: Support for fuzzy inference system structures will be removed

Support for representing fuzzy inference systems as structures will be removed in a future release. Use mamfis and sugfis objects with this function instead. To convert existing fuzzy inference system structures to objects, use the convertfis function.

This change was announced in R2018b. Using fuzzy inference system structures with this function issues a warning starting in R2019b.