https://github.com/cran/aqp
Revision 01117710b462f4328b6f6f5f775726d27d3730da authored by Dylan Beaudette on 24 September 2018, 19:40:03 UTC, committed by cran-robot on 24 September 2018, 19:40:03 UTC
1 parent 1880825
Tip revision: 01117710b462f4328b6f6f5f775726d27d3730da authored by Dylan Beaudette on 24 September 2018, 19:40:03 UTC
version 1.16-3
version 1.16-3
Tip revision: 0111771
shannonEntropy.Rd
\name{shannonEntropy}
\alias{shannonEntropy}
\title{Shannon Entropy}
\description{A very simple implementation of Shannon entropy.}
\usage{
shannonEntropy(x, b = 2)
}
\arguments{
\item{x}{vector of probabilities [0,1], must sum to 1, should not contain NA}
\item{b}{logarithm base}
}
\details{0s are automatically removed by na.rm=TRUE, as (0 * log(0) = Nan)}
\note{The result is the normalized Shannon entropy when b = length(x) (Kempen et al, 2009).}
\value{A single numeric value.}
\references{
Kempen, Bas, Dick J. Brus, Gerard B.M. Heuvelink, and Jetse J. Stoorvogel. 2009. "Updating the 1:50,000 Dutch Soil Map Using Legacy Soil Data: A Multinominal Logistic Regression Approach." Geoderma 151: 311-26. doi:10.1016/j.geoderma.2009.04.023
Shannon, Claude E. (July-October 1948). "A Mathematical Theory of Communication". Bell System Technical Journal. 27 (3): 379-423. doi:10.1002/j.1538-7305.1948.tb01338.x
}
\examples{
# a very simple example
p <- c(0.25, 0.25, 0.4, 0.05, 0.05)
shannonEntropy(p)
}
\keyword{manip}
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