genmf {FuzzyR}

Fuzzy membership function generator

Description

To generate the corresponding membership function f(x), also called fuzzy set, according to type and parameters

Usage

genmf(mf.type, mf.params)

Arguments

mf.type

The membership function type

mf.params

The parameters for a membership function

Details

Built-in membership function types are: 'gbellmf', 'it2gbellmf', 'singletonmf', 'linearmf', 'gaussmf', 'trapmf', 'trimf'.

mf.params for

• 'gbellmf' is c(a, b, c), where a denotes the width, b is usually positive and c locates the center of the curve.
  

• 'it2gbellmf' is c(a.lower, a.upper, b, c), where a.upper > a.lower when b > 0 and a.upper < a.lower when b < 0
  

• 'singletonmf' is c(c), where c is the location where the membership grade is 1.
  

• 'linearmf' is c(...), which are the coefficients of the linear membership function.
  

• 'gaussmf' is c(sig, c), which are the parameters for exp(-(x - c)^2/(2 * sig^2)).
  

• 'trapmf' is c(a, b, c, d), where a and d locate the "feet" of the trapezoid and b and c locate the "shoulders".
  

• 'trimf' is c(a, b, c), where a and c locate the "feet" of the triangle and b locates the peak.

Note that users are able to define their own membership functions.

Value

The desired type of membership function f(x), where x is a generic element of U, which is the universe of discourse for a fuzzy set

Author(s)

Chao Chen

Examples

mf <- genmf('gbellmf', c(1,2,3))
evalmf(1:10, mf)