dtw (version 1.23-1)

warpArea: Compute Warping Path Area

Description

Compute the area between the warping function and the diagonal (no-warping) path, in unit steps.

Usage

warpArea(d)

Value

The area, not normalized by path length or else.

Arguments

d

an object of class dtw

Author

Toni Giorgino

Details

Above- and below- diagonal unit areas all count plus one (they do not cancel with each other). The "diagonal" goes from one corner to the other of the possibly rectangular cost matrix, therefore having a slope of M/N, not 1, as in slantedBandWindow().

The computation is approximate: points having multiple correspondences are averaged, and points without a match are interpolated. Therefore, the area can be fractionary.

Examples

  ds<-dtw(1:4,1:8);

  plot(ds);lines(seq(1,8,len=4),col="red");

  warpArea(ds)

  ## Result: 6
  ##  index 2 is 2 while diag is 3.3  (+1.3)
  ##        3    3               5.7  (+2.7)
  ##        4   4:8 (avg to 6)    8   (+2  )
  ##                                 --------
  ##                                     6