Fuzzy Logic Toolbox

sigmf

Sigmoidally-shaped built-in membership function.

Synopsis

y = sigmf(x,[a c])

Description

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

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. You can find out more about this in this chapter's entries for dsigmf and psigmf.

Examples

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

See Also

dsigmf, gaussmf, gauss2mf, gbellmf, evalmf, mf2mf, pimf, psigmf, smf, trapmf, trimf, zmf

showrule

smf