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Convert type-2 fuzzy inference system into type-1 fuzzy inference system



fisT1 = convertToType1(fisT2) converts the type-2 fuzzy inference system fisT2 into a type-1 fuzzy inference system fisT1.


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Create a type-2 fuzzy inference system. For this example, Create a type-2 Mamdani FIS with two inputs, one output.

fisT2 = mamfistype2("NumInputs",2,"NumOutputs",1);

View the membership function for the first input variable.


Figure contains an axes object. The axes object with title Footprint of uncertainty (FOU) contains 12 objects of type line, patch, text. These objects represent UpperMF, LowerMF, FOU.

Convert fisT2 into a type-1 fuzzy inference system.

fisT1 = convertToType1(fisT2);

View the converted membership functions for the first input variable.


Figure contains an axes object. The axes object contains 6 objects of type line, text.

Input Arguments

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Type-2 fuzzy inference system, specified as a mamfistype2 or sugfistype2 object.

Output Arguments

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Type-1 fuzzy inference system, returned as one of the following:

  • mamfis object when fisT2 is a mamfistype2 object

  • sugfis object when fisT2 is a sugfistype2 object

The properties of fisT1 match the corresponding properties of fisT2, except that each type-2 membership function is converted to a type-1 membership function. The parameters of each type-1 membership function in fisT1 match the upper membership function parameters of the corresponding type-2 membership function in fisT2.

Alternative Functionality


You can interactively convert a type-2 FIS into a type-1 FIS using the Fuzzy Logic Designer app. You can then export the system to the MATLAB® workspace.

Version History

Introduced in R2019b