divcmax | R Documentation |
For a given dissimilarity matrix, this function calculates the maximal value of Rao's diversity coefficient over all frequency distribution. It uses an optimization technique based on Rosen's projection gradient algorithm and is verified using the Kuhn-Tucker conditions.
divcmax(dis, epsilon, comment)
dis |
an object of class |
epsilon |
a tolerance threshold : a frequency is non null if it is higher than epsilon. |
comment |
a logical value indicating whether or not comments on the optimization technique should be printed. |
Returns a list
value |
the maximal value of Rao's diversity coefficient. |
vectors |
a data frame containing four frequency
distributions : |
Stéphane Champely Stephane.Champely@univ-lyon1.fr
Sandrine Pavoine pavoine@mnhn.fr
Rao, C.R. (1982) Diversity and dissimilarity coefficients: a unified approach. Theoretical Population Biology, 21, 24–43.
Gini, C. (1912) Variabilità e mutabilità. Universite di Cagliari III, Parte II.
Simpson, E.H. (1949) Measurement of diversity. Nature, 163, 688.
Champely, S. and Chessel, D. (2002) Measuring biological diversity using Euclidean metrics. Environmental and Ecological Statistics, 9, 167–177.
Pavoine, S., Ollier, S. and Pontier, D. (2005) Measuring diversity from dissimilarities with Rao's quadratic entropy: are any dissimilarities suitable? Theoretical Population Biology, 67, 231–239.
data(elec88) # Dissimilarity matrix. d0 <- dist(elec88$xy/100) # Frequency distribution maximizing spatial diversity in France # according to Rao's quadratic entropy. France.m <- divcmax(d0) w0 <- France.m$vectors$num v0 <- France.m$value idx <- (1:94) [w0 > 0] if(!adegraphicsLoaded()) { # Smallest circle including all the 94 departments. # The squared radius of that circle is the maximal value of the # spatial diversity. w1 <- elec88$xy[idx, ]/100 w.c <- apply(w1 * w0[idx], 2, sum) plot(elec88$xy[, 1]/100, elec88$xy[, 2]/100, asp=1) symbols(w.c[1], w.c[2], circles = sqrt(v0), inches = FALSE, add = TRUE) s.value(elec88$xy/100, w0, add.plot = TRUE) }
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.