# TopoS

From klaR v0.6-11
by Uwe Ligges

##### Computation of criterion S of a visualization

`TopoS`

computes one version of the criterion `stress`

as i.e.
known from `sammon`

for a given visualization.

- Keywords
- internal

##### 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.

##### concept

S criterion

##### See Also

##### 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]))))
```

*Documentation reproduced from package klaR, version 0.6-11, License: GPL-2*

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