R: Computation of criterion S of a visualization

TopoS {klaR} | R Documentation

## 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`)

### 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`.

### Value

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

### Author(s)

Nils Raabe

### See Also

`EDAM`

### Examples

    # 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]))))

[Package klaR version 0.6-12 Index]