+++ /dev/null
-# Shorthand: map 1->1, 2->2, 3->3, 4->1, ..., 149->2, 150->3, ... (is base==3)
-I = function(i, base)
- (i-1) %% base + 1
-
-# Compute the sum of (normalized) sum of squares of closest distances to a medoid.
-# Note: medoids can be a big.matrix
-computeDistortion = function(series, medoids)
-{
- if (bigmemory::is.big.matrix(medoids))
- medoids = medoids[,] #extract standard matrix
-
- n = ncol(series) ; L = nrow(series)
- distortion = 0.
- for (i in seq_len(n))
- distortion = distortion + min( colSums( sweep(medoids,1,series[,i],'-')^2 ) / L )
-
- sqrt( distortion / n )
-}