klaR (version 0.6-15)

TopoS: Computation of criterion S of a visualization

Description

TopoS computes one version of the criterion stress as i.e. known from sammon for a given visualization.

Usage

TopoS(EV.dist, Cells.dist)

Arguments

EV.dist

a symmetric distance matrix consisting of distances in the origin space (dx)

Cells.dist

a symmetric distance matrix consisting of distances in the target space (dy)

Value

TopoS returns a numeric between zero and one which is the criterion S of the given visualization.

Details

TopoS first performs a homogeneous linear regression where dx is predicted by dy. Then the residual sum of squares of this regression is computed and divided by the sum of squared dx. Finally one minus the square root of the latter result defines S.

See Also

EDAM

Examples

# NOT RUN {
# Compute S for the MDS visualization of the german business data
data(B3)
plot(cmdscale(dist(B3[, 2:14])), col = rainbow(4)[B3[, 1]], pch = 16)
TopoS(dist(B3[, 2:14]), dist(cmdscale(dist(B3[, 2:14]))))
# }