# spatialSign

From caret v4.60
by Max Kuhn

##### Compute the multivariate spatial sign

Compute the spatial sign (a projection of a data vector to a unit length circle). The spatial sign of a vector `w`

is `w /norm(w)`

.

- Keywords
- manip

##### Usage

```
spatialSign.default(x)
spatialSign.matrix(x)
spatialSign.data.frame(x)
```

##### Arguments

- x
- an object full of numeric data (which should probably be scaled). Factors are not allowed. This could be a vector, matrix or data frame.

##### Value

- A vector, matrix or data frame with the same dim names of the original data.

##### References

Serneels et al. Spatial sign preprocessing: a simple way to impart moderate robustness to multivariate estimators. J. Chem. Inf. Model (2006) vol. 46 (3) pp. 1402-1409

##### Examples

```
spatialSign(rnorm(5))
spatialSign(matrix(rnorm(12), ncol = 3))
# should fail since the fifth column is a factor
try(spatialSign(iris), silent = TRUE)
spatialSign(iris[,-5])
trellis.par.set(caretTheme())
featurePlot(iris[,-5], iris[,5], "pairs")
featurePlot(spatialSign(scale(iris[,-5])), iris[,5], "pairs")
```

*Documentation reproduced from package caret, version 4.60, License: GPL-2*

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