Learn R Programming

agop (version 0.1-3)

owmax: WMax, WMin, OWMax, and OWMin Operators

Description

Computes the (Ordered) Weighted Maximum/Minimum.

Usage

owmax(x, w = rep(Inf, length(x)))

owmin(x, w = rep(-Inf, length(x)))

wmax(x, w = rep(Inf, length(x)))

wmin(x, w = rep(-Inf, length(x)))

Arguments

x
numeric vector to be aggregated
w
numeric vector of the same length as x; weights

Value

  • single numeric value

Details

The OWMax operator is given by $$\mathsf{OWMax}_\mathtt{w}(\mathtt{x})=\bigvee_{i=1}^{n} w_{i}\wedge x_{{i}}$$ where $x_{{i}}$ denotes the $i$-th greatest value in x.

The OWMin operator is given by $$\mathsf{OWMin}_\mathtt{w}(\mathtt{x})=\bigwedge_{i=1}^{n} w_{i}\vee x_{{i}}$$

The WMax operator is given by $$\mathsf{WMax}_\mathtt{w}(\mathtt{x})=\bigvee_{i=1}^{n} w_{i}\wedge x_{i}$$

The WMin operator is given by $$\mathsf{WMin}_\mathtt{w}(\mathtt{x})=\bigwedge_{i=1}^{n} w_{i}\vee x_{i}$$

OWMax and WMax return the greatest value in x by default, and OWMin and WMin - the smallest value in x.

Note that e.g. in the case of OWMax operator the aggregation w.r.t. w gives the same result as that of w.r.t. sort(w). Moreover, classically, it is assumed that if we agregate vectors with elements in $[a,b]$, then the largest weight should be equal to $b$.

There is a strong connection between the OWMax/OWMin operators and the Sugeno integrals. Additionally, it may be shown that the OWMax and OWMin classes are equivalent.

Moreover, index_h for integer data is a particular OWMax operator.

References

Dubois D., Prade H., Testemale C., Weighted fuzzy pattern matching, Fuzzy Sets and Systems 28, 1988, pp. 313-331.

See Also

Other aggregation_operators: owa, wam