addOutput

Add output variable to fuzzy inference system

Syntax

fisOut = addOutput(fisIn)

fisOut = addOutput(fisIn,range)

fisOut = addOutput(___,Name,Value)

Description

fisOut = addOutput(fisIn) adds a default output variable to fisIn, and returns the resulting fuzzy system in fisOut. This output variable has a default name, default range, and no membership functions.

fisOut = addOutput(fisIn,range) adds an output variable with the specified range.

fisOut = addOutput(___,Name,Value)configures the output variable using one or more name-value pair arguments.

Examples

Add Output Variable to Fuzzy Inference System

Create a Mamdani fuzzy inference system.

fis = mamfis('Name','tipper');

Add an output variable with default specifications.

fis = addOutput(fis);

You can configure the output variable properties using dot notation. For example, specify the name and range for the variable.

fis.Outputs(1).Name = "tip";
fis.Outputs(1).Range = [10 30];

View the output variable.

fis.Outputs(1)

ans = 
  fisvar with properties:

                   Name: "tip"
                  Range: [10 30]
    MembershipFunctions: [0x0 fismf]

You can also specify the variable name and range when you add it to the fuzzy system.

fis2 = mamfis('Name','tipper');
fis2 = addOutput(fis2,[10 30],'Name',"tip");

Add Output Variable with Membership Functions

Create a Sugeno fuzzy inference system.

fis = sugfis('Name',"tipper");

Add an output variable with three constant membership functions distributed over the output range.

fis = addOutput(fis,'NumMFs',3,'MFType',"constant");

View the membership functions.

fis.Outputs(1).MembershipFunctions

ans = 
  1x3 fismf array with properties:

    Type
    Parameters
    Name

  Details:
         Name        Type       Parameters
         _____    __________    __________

    1    "mf1"    "constant"         0    
    2    "mf2"    "constant"       0.5    
    3    "mf3"    "constant"         1    

Input Arguments

fisIn — Fuzzy inference system

mamfis object | sugfis object | mamfistype2 object | sugfistype2 object

Fuzzy inference system, specified as one of the following objects.

• mamfis object — Mamdani fuzzy inference system

• sugfis object — Sugeno fuzzy inference system

• mamfistype2 object — Type-2 Mamdani fuzzy inference system

• sugfistype2 object — Type-2 Sugeno fuzzy inference system

range — Variable range

[0 1] (default) | two-element vector

Variable range, specified as a two-element element vector where the first element is less than the second element. The first element specifies the lower bound of the range, and the second element specifies the upper bound of the range.

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: fis = addOutput(fis,NumMFs=3)

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: fis = addOutput(fis,'NumMFs',3)

Name — Variable name

string | character vector

Variable name, specified as a string or character vector.

NumMFs — Number of membership functions

0 (default) | nonnegative integer

Number of membership functions, specified as a nonnegative integer.

MFType — Membership function type

"trimf" (default) | "gaussmf"

Membership function type, specified as one of the following values.

• "trimf" — Triangular membership functions for the outputs of Mamdani system

• "gaussmf" — Gaussian membership functions for the outputs of Mamdani systems

• "constant" — Constant membership functions for the outputs of Sugeno systems

• "linear" — Linear membership functions for the outputs of Sugeno systems. To add an output variable with linear membership functions, your FIS must have at least one input variable.

The membership functions are uniformly distributed over the variable range with approximately 80% overlap in the membership function supports.

Output Arguments

fisOut — Updated fuzzy inference system

mamfis object | sugfis object | mamfistype2 object | sugfistype2 object

Updated inference system, returned as one of the following objects.

• mamfis object — Mamdani fuzzy inference system

• sugfis object — Sugeno fuzzy inference system

• mamfistype2 object — Type-2 Mamdani fuzzy inference system

• sugfistype2 object — Type-2 Sugeno fuzzy inference system

fisOut contains the added output variable, with all other properties matching the properties of fisIn.

Version History

Introduced in R2018b

R2018b: Replaces addvar

This function replaces addvar for adding output variables to a fuzzy inference system.