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The function returns the degree of membership using the product of two sigmoidal functions given the real input x and the parameters shape parameter for the s-shaped transition area a, center of the s-shaped transition area b, shape parameter of the z-shaped transition area c, and center of the z-shaped transition area d of the function.

Implementation

 y := sigmf(x, a = a, c = b) * sigmf(x, a = -c, c = d);

Syntax

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

Examples

Functions.psigmf(   8, a=2, b=3, c=5, d=8); // 0.4999773..
Functions.psigmf( 6.9, a=2, b=3, c=5, d=8); // 0.9955219..
Functions.psigmf(   3, a=2, b=3, c=5, d=8); // 0.4999999..
Functions.psigmf(  10, a=2, b=3, c=5, d=8); // 4.53978e-05

See also

evalmf, rampmf, trimf, trapmf, smf, sigmf, gaussmf, gbellmf

y = psigmf(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: Shape parameter controlling the width of s-shaped transition area (higher values → steeper transition)
b	Type: Real Description: Center of s-shaped transition area
c	Type: Real Description: Shape parameter controlling the width of z-shaped transition area (higher values → steeper transition)
d	Type: Real Description: Center of z-shaped transition area

y	Type: Real Description: Degree of membership