# Sigmoidal MF

Sigmoidal membership function in Simulink software

## Description

The Sigmoidal MF block implements a sigmoidal membership function given by

$f\left(x\right)=\frac{1}{1+\mathrm{exp}\left(-a\left(x-c\right)\right)}$

When the sign of a is positive the curve increases from left to right. Conversely, when the sign of a is negative the curve decreases from left to right. The parameter c sets the point of inflection of the curve.

`sigmf`