caret (version 4.60)

spatialSign: Compute the multivariate spatial sign

Description

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).

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")