psd2edm {edmcr}

Linear Matrix Operator

Description

psd2edm Transform a positive semi-definite matrix to a Euclidean Distance Matrix

Usage

psd2edm(S, V = NULL)

Arguments

S

A symmetric, positive semi-definite matrix

V

A projection matrix satisfying V'1 = 0 and VV' = I

Details

The psd2edm function performs the inverse operation of the edm2psd function, taking a matrix in S_{n-1}^{+} and transforming it to a matrix in D_{n}^{-}.

psd2edm(S_{n-1}^{+}) = D_{n}^{-}

Therefore, psd2edm on S_{n-1}^{+} is the inverse operator of edm2psd on D_{n}^{-}.

For a symmetric positive semi-definite matrix S, psd2edm(S) will be in D_{n}^{-}.

Value

D A Euclidean Distance Matrix.

See Also

gram2edm edm2psd

Examples

XY <- cbind(runif(100,0,1),runif(100,0,1))
S <- edm2psd(as.matrix(dist(XY)))
D <- psd2edm(S)