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trimf

Triangular membership function

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Syntax

y = trimf(x,params)

Description

This function computes fuzzy membership values using a triangular membership function. You can also compute this membership function using a fismf object. For more information, see fismf Object.

This membership function is related to the trapmf, linsmf, and linzmf membership functions.

y = trimf(x,params) returns fuzzy membership values computed using the following triangular membership function:

f(x;a,b,c)={0,x≤ax−ab−a,a≤x≤bc−xc−b,b≤x≤c0,c≤x}

or, more compactly:

f(x;a,b,c)=max(min(x−ab−a,c−xc−b),0)

To define the membership function parameters, specify params as the vector [a b c].

Membership values are computed for each input value in x.

example

Examples

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Open Live Script

Specify input values across the universe of discourse.

x = 0:0.1:10;

Evaluate membership function for the input values.

y = trimf(x,[3 6 8]);

Plot the membership function.

plot(x,y)
title('trimf, P = [3 6 8]')
xlabel('x')
ylabel('Degree of Membership')
ylim([-0.05 1.05])

Figure contains an axes object. The axes object with title trimf, P = [3 6 8], xlabel x, ylabel Degree of Membership contains an object of type line.

Input Arguments

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Input values for which to compute membership values, specified as a scalar or vector.

Membership function parameters, specified as the vector [a b c]. Parameters a and c define the feet of the membership function, and b defines its peak.

Output Arguments

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Membership value returned as a scalar or a vector. The dimensions of y match the dimensions of x. Each element of y is the membership value computed for the corresponding element of x.

Alternative Functionality

fismf Object

You can create and evaluate a fismf object that implements the trimf membership function.

mf = fismf("trimf",P);
Y = evalmf(mf,X);

Here, X, P, and Y correspond to the x, params, and y arguments of trimf, respectively.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced before R2006a

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See Also

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