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The function returns the degree of membership using a trapezoidal function given the real input x and the parameters lower bound of the support a, the lower bound of the core b, the upper bound of the core c, and the upper bound of the support d.

Implementation

y := max( min( 1, min( (x - a)/(b - a), (d - x)/(d - c)) ), 0 );

Syntax

Functions.trapmf(x, a, b, c, d);

Examples

Functions.trapmf( 5, a=2, b=4, c=6, d=8); // 1.0
Functions.trapmf( 2, a=2, b=4, c=6, d=8); // 0.0
Functions.trapmf( 9, a=2, b=4, c=6, d=8); // 0.0
Functions.trapmf( 7, a=2, b=4, c=6, d=8); // 0.5

See also

evalmf, rampmf, trimf, smf, sigmf, pimf, psigmf, gaussmf, gbellmf

y = trapmf(x, a, b, c, d)

x	Type: Real Description: Input value for which the degree of membership is to be computed
a	Type: Real Description: Lower bound for the support (i.e., f(a) = 0)
b	Type: Real Description: Lower bound for the core (i.e., f(b) = 1)
c	Type: Real Description: Upper bound for the core (i.e., f(c) = 1)
d	Type: Real Description: Upper bound for the support(i.e., f(d) = 0)

y	Type: Real Description: Degree of membership