searchMaxLambda {ExcessMass} | R Documentation |
Searching For A Maximal Lambda
Description
Function which gives a rough approximation of maximal \lambda
.
Usage
searchMaxLambda(x, limcount = 4, step = 1.05, trylambda = 0.01)
Arguments
x |
data in form of a vector |
limcount |
divided by the square root of the number of data points. The result determines the cut off value. |
step |
determines step size |
trylambda |
initial |
Details
Excess mass is calculated for trylambda
. In case the resulting excess mass is larger (smaller) than the cut off value, trylambda
is set as trylambda * step
(respectively trylambda / step
) and excess mass is calculated again until it is smaller (larger) than the cut off value. The corresponding trylambda
is returned.
The approximation is done allowing only for one \lambda
-cluster, as scans including more \lambda
-clusters have high computational costs due to the recursive structure of the algorithm.
Value
trylambda
calculated as described in Details.
Author(s)
Marc-Daniel Mildenberger mildenberger.stat@web.de, based on earlier code from Dr. Guenther Sawitzki gs@statlab.uni-heidelberg.de
References
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
See Also
excessm, exmplot, exmsilhouette, mexmsilhouette
Examples
library(MASS)
attach(geyser)
#Calculating Lambda using standard settings
searchMaxLambda(duration)
#Calculating Lambda, reducing cut off value and step. Setting another initial lambda
searchMaxLambda(duration, limcount = 5, step = 1.01, trylambda = 1)