distortions

Description

the same objects are represented by two different datasets: this function computes the pairwise distances in both datasets, and the distortions induced by these distance matrices (see Aupetit, 2007)

Usage

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distortions(origdata, projdata)

Arguments

origdata

n x d original dataset

projdata

n x q projected/transformed dataset

Value

list object, with components: - compress : vector of n compressive distortion values - stretch : vector of n stretching distortion values

Author(s)

Pierrick Bruneau

References

Aupetit, M. (2007) Visualizing distortions and recovering topology in continuous projection techniques. Neurocomputing. Pages 1304-1330.

See Also

computeKernel computeProjectionFromKernel

Examples

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data(iris)
irisdat <- as.matrix(cbind(iris[,1:4], rep(NA, 150)))
irisdat[sample(1:150,4),5] <- 1:4
proj <- computeProjectionFromKernel(computeKernel(irisdat))
dists <- distortions(irisdat[,1:4], proj)