fuzzify {fuzzyreg}

Convert Real Value Numbers to Triangular Fuzzy Numbers

Description

Uses naive alternative methods to approximate triangular fuzzy numbers from real value number input data.

Usage

fuzzify(x, y = NULL, method = "mean", err = 0, dimnames = NULL, ...)

Arguments

x

numeric vector.

y

vector that can be coerced to factor (optional).

method

character vector specifying the conversion method. See Details.

err

numeric vector. Error term for the error method.

dimnames

list of length 2 giving names of the x and y variables.

...

additional parameters passed to other functions.

Details

Converts crisp numbers in x to a triangular fuzzy number (TFN). Optionally, values in y can be used as grouping elements and are coerced to a factor.

Method mean calculates the central value of a TFN as the mean of x given y, and the left and right spreads as standard deviations.

Method median gives the central values as a median and left and right spreads are calculated as distance of the first and third quartile from the median.

Method zero inserts zeros to both spreads.

Method error uses a user-defined numeric value or vector for the spreads. The length of the numeric vector in argument err must be in (1, length(x), 2 * length(x)).

Value

A data.frame with columns representing the central value, left and right spread of x and the values in y coerrced to a factor. Attempt is made to inherit names from the input data. Methods mean and zero will return symmetric TFNs, whereas methods median and error can return non-symmetric TFNs depending on input data and the data or the values in the err argument.

Examples

fuzzify(1:5)
fuzzify(1:6, c(1,1,1,2,2,2), method = "err", err = runif(6) * 1e-3)