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Membership functions

Membership functions

A membership function is a function that allows to calculate the membership degree of a random element of the universal set to a fuzzy set. Consequently, the domain of a membership function should be within the range [0, 1].

In most cases, the membership function is continuous and monotonic.

Classes of membership functionsDescription
CConstantMembershipFunctionClass for implementing a membership function as a straight line in parallel with the coordinate axis
CCompositeMembershipFunctionClass for implementing a composition of membership functions
CDifferencTwoSigmoidalMembershipFunctionClass for implementing the membership function in the form of a difference between two sigmoid functions with the A1, A2, C1 and C2 parameters
CGeneralizedBellShapedMembershipFunctionClass for implementing a generalized bell-shaped membership function with A, B and C parameters
CNormalCombinationMembershipFunctionClass for implementing a two-sided Gaussian membership function with the B1, B2, Sigma1 and Sigma2 parameters
CNormalMembershipFunctionClass for implementing a symmetrical Gaussian membership function with the B and Sigma parameters
CP_ShapedMembershipFunctionClass for implementing a pi-shaped membership function with the A, B, C and D parameters
CProductTwoSigmoidalMembershipFunctionClass for implementing the membership function in the form of a product of two sigmoid functions with the A1, A2, C1 and C2 parameters
CS_ShapedMembershipFunctionClass for implementing an S-like membership function with the A and B parameters
CTrapezoidMembershipFunctionClass for implementing a trapezoidal membership function with the X1, X2, X3 and X4 parameters
CTriangularMembershipFunctionClass for implementing a triangle membership function with the X1, X2 and X3 parameters
CSigmoidalMembershipFunctionClass for implementing a sigmoid membership function with the A and C parameters
CZ_ShapedMembershipFunctionClass for implementing a z-like membership function with the A and B parameters.
IMembershipFunctionBasic class for all membership function classes.
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