linsmf

Linear s-shaped saturation membership function

Since R2022a

Syntax

y = linsmf(x,params)

Description

This function computes fuzzy membership values using a linear s-shaped 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 trimf, trapmf, and linzmf membership functions.

y = linsmf(x,params) returns fuzzy membership values computed using a linear s-shaped saturation membership function.

• When a < b:

  $$f\left(x;a,b\right)=\left\{\begin{array}{ll}0,\hfill & x<a\hfill \\ \frac{x-a}{b-a},\hfill & a\le x\le b\hfill \\ 1,\hfill & x>b\hfill \end{array}\right\}$$

• When a = b:

  $$f\left(x;a,b\right)=\left\{\begin{array}{cc}0,& x<a\\ 1,& x\ge a\end{array}\right\}$$

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

Membership values are computed for each input value in x.

Examples

Linear S-Shaped Membership Function

Specify input values across the universe of discourse.

x = 0:0.1:10;

Evaluate a linear s-shaped membership function for the input values.

y = linsmf(x,[4 6]);

Plot the membership function.

plot(x,y)
xlabel("linsmf, P = [4 6]")
ylabel("Membership")
ylim([-0.05 1.05])

Input Arguments

x — Input values

scalar | vector

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

params — Membership function parameters

vector of length two

Membership function parameters, specified as the vector [a b]. Parameter a defines the foot of the membership function, and b defines its shoulder. Setting a equal to b produces a crisp membership function.

Output Arguments

y — Membership value

scalar | vector

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 linsmf membership function.

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

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

Extended Capabilities

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

Version History

Introduced in R2022a