excessm {ExcessMass} | R Documentation |
Algorithm which calculates the empirical excess mass for a given \lambda
and given maximal number of modes.
excessm(x, lambda, M = 1, UpToM = FALSE)
x |
data in form of a vector |
lambda |
|
M |
maximal number of modes |
UpToM |
if true, the intervals for modes up to M are returned |
intervals |
Matrix containing the empirical |
excess_mass |
returns a vector with excess masses, the |
Please note that an allowance for M
modes does not necessarily result in M
\lambda
-clusters. Hence, the number of intervals returned can be smaller than M
. In this case a warning will be displayed. The vector excess_mass
does have less than M
entries.
Marc-Daniel Mildenberger mildenberger.stat@web.de, based on earlier code from Dr. Guenther Sawitzki gs@statlab.uni-heidelberg.de
Muller, D. W. and Sawitzki, G., 09.1991, "Excess Mass Estimates and Tests for Multimodality", Journal of the American Statistical Association , Vol. 86, No. 415, pp. 738–746, http://www.jstor.org/stable/2290406
exmplot, exmsilhouette, mexmsilhouette
library(MASS)
attach(geyser)
##calculating excess mass for duration of 'Old Faithful Geyser' for lambda=0.2 allowing for one mode
excessm(duration, lambda=0.2)
##same as above, but allowing for up to three modes
excessm(duration, lambda=0.2, M=3)
#returns the intervals for modes 1,2 and 3
excessm(duration, lambda=0.2, M=3, UpToM=TRUE)