X.entropy {RoughSets}

The entropy measure

Description

An auxiliary function for the qualityF parameter in the FS.greedy.heuristic.reduct.RST, FS.DAAR.heuristic.RST and FS.greedy.heuristic.superreduct.RST functions. It is based on entropy as a measure of information(Shannon, 1948).

Usage

X.entropy(decisionDistrib)

Arguments

decisionDistrib

an integer vector corresponding to a distribution of attribute values

Value

a numeric value indicating entropy of an attribute.

Author(s)

Andrzej Janusz

References

C. E. Shannon, "A Mathematical Theory of Communication", Bell System Technical Journal, vol. 27, p. 379 - 423, 623 - 656 (1948).