implementation of Sigmoid Membership Function

hi

how to implement sigmoid membership function that takes just one value (singleton) as in picture below :

when i add MF in the matlab and select the MF type as "sigmf" it draws a MF that takes 2 parameters as in the picture below , so how could i implement MF as in the picture above ?

[Maria]

any answer?

[Maria]

please anyone can answer me ?

[José-Luis]

I am maybe misunderstanding, but you might have to use a different membership function. One that is not a sigmoid. I don't see how what you show in the upper plot can be interpreted as a sigmoid.

A sigmoid, as implemented by Matlab takes two parameters, you could make one of those parameters a function of the other so you have only one variable, but I still don't understand what you are trying to achieve.

[Maria]

Many thanks to José-Luis , so the question is , which type of membership function in the picture below and how could i implement this type .

[José-Luis]

If one squints the right way, it looks like a series of trapezoidal membership functions.

 doc trapmf