flou {multiv}R Documentation

Fuzzy Coding (3-Way)

Description

Simple fuzzy, or piecewise linear, coding of a vector: each value in the vector is replaced by a 1 (if it is above or equal to the 67th quantile), by a 0 (if it is below or equal to the 33rd quantile), and by a linearly interpolated value between 0 and 1 (if it lies between the 33rd and 67th quantiles).

Usage

flou(a)

Arguments

a real-valued vector, with no missing values.

Value

matrix of length(a) rows, and two columns. The first column contains the fuzzily coded values of a, and the second column contains their complements. Hence each row of this returned matrix necessarily sums to 1.

BACKGROUND

This form of coding is suitable for a subsequent correspondence analysis. When all variable have been fuzzily (or logically) coded, the row masses (proportional to the row sums) are identical.

References

J.-P. Benzecri Correspondence Analysis Handbook Marcel Dekker, Basel, 1992.

F.J. Gallego, Codage flou en analyse des correspondances, Les Cahiers de l'Analyse des Donnees vol. VII, 413-430, 1982

See Also

logique, ca, supplr, supplc.

Examples

# Fuzzy coding of input variables, `a', `b', `c':
a.fuzz <- flou(a)
b.fuzz <- flou(b)
c.fuzz <- flou(c)
newdata <- cbind(a.fuzz, b.fuzz, c.fuzz)
ca.newdata <- ca(newdata)


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