popsom (version 6.0)

map.convergence: SOM Quality Assessment

Description

Evaluate the quality of a SOM using embedding accuracy and estimated topographical accuracy.

Usage

map.convergence(map,conf.int=.95,k=50,verb=TRUE,ks=TRUE)

Arguments

map

an object of type 'map'.

conf.int

is the confidence interval of the quality assessment.

k

number of samples to use in the computation of the estimated topographical accuracy.

verb

if true reports the two convergence components separately, otherwise it will report a linear combination of the two indices.

ks

if true uses the Kolmogorov-Smirnov convergence test otherwise a convergence test based on variance and means is performed.

Value

A single value or a pair of values: 1) embedding accuracy 2) estimated topographic accuracy. The structure of the return value depends on the 'verb' switch.

References

"SOM Quality Measures: A Statistical Approach," Lutz Hamel, WSOM16, 2016.

Examples

# NOT RUN {
data(iris)

## set data frame and labels
df <- subset(iris,select=-Species)
labels <- subset(iris,select=Species)

## build a map
m <- map.build(df, labels, xdim=15, ydim=10, train=1000)

## map quality
map.convergence(m)

# }