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sigmf

Sigmoidal membership function

Syntax

y = sigmf(x,[a c]) 

Description

The sigmoidal function, sigmf(x,[a c]), as given in the following equation by f(x,a,c) is a mapping on a vector x, and depends on two parameters a and c.

f(x,a,c)=11+ea(xc)

Depending on the sign of the parameter a, the sigmoidal membership function is inherently open to the right or to the left, and thus is appropriate for representing concepts such as “very large” or “very negative.” More conventional-looking membership functions can be built by taking either the product or difference of two different sigmoidal membership functions. For more information see dsigmf and psigmf.

Examples

collapse all

x = 0:0.1:10;
y = sigmf(x,[2 4]);
plot(x,y)
xlabel('sigmf, P = [2 4]')
ylim([-0.05 1.05])

Extended Capabilities

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

Introduced before R2006a