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# dsigmf

Difference between two sigmoidal functions membership function

## Syntax

```y = dsigmf(x,[a1 c1 a2 c2])
```

## Description

The sigmoidal membership function used depends on the two parameters a and c and is given by

$\text{\hspace{0.17em}}\text{\hspace{0.17em}}\text{\hspace{0.17em}}\text{\hspace{0.17em}}\text{\hspace{0.17em}}f\left(x;a,c\right)=\frac{1}{1+{e}^{-a\left(x-c\right)}}$

The membership function dsigmf depends on four parameters, a1, c1, a2, and c2, and is the difference between two of these sigmoidal functions.

f1(x; a1, c1) - f2(x; a2, c2)

The parameters are listed in the order: [a1 c1 a2 c2].

## Examples

expand all

### Obtain Difference of Two Sigmoidal Functions

```x=0:0.1:10;
y=dsigmf(x,[5 2 5 7]);
plot(x,y)
xlabel('dsigmf, P=[5 2 5 7]')
```