# Re: How is the degree of membership calculated?

Eric GAUDET (egaudet@francenet.fr)
Mon, 18 May 1998 03:35:28 +0200 (MET DST)

CRPFALKSD wrote:

> >Each MF, as represented above, is a piecewise linear function of one
> >variable so, for example,
> >Just_Right(X) =
> > 0 for x < 60
> > (x-60)/5 for 60 <= x < 65
> > 1-(x-65)/5 for 65 <= x <= 70
> > 0 for x > 70.
> >Normally one then takes the maximum value over all of the memberships
> >for the linguistic set and assigns that to the result. Hence, in the
> >above example one would assert that the temperature is Just Right.
>
> So for a temperature with a degree of membership Warm, the figures would read:
> 0 for x < 65
> (x-65)/5 for 65 <= x < 70
> 1-(x-70)/5 for 70 <= x <= 85

NO ! it's 1-(x-70)/15 for 70 <=x<=85, since 85-70=15 !degree of membership is a
number between 0 and 1 (percent of membership)

> 0 for x > 85
>
> And if the temperature was 80, then we use the third formula like such:
> 1-(80-70)/5 since 70 <= 80 <=85 the result=?? (I get -1.0 ??)
>

with 1-(80-70)/15 the result is 1/3, so it' a correct value