wcc {ptw} | R Documentation |
Functions to calculate weighted auto- and cross-correlation measures. The wcc is a suitable measure for the similarity of two patterns when features may be shifted. Identical patterns lead to a wcc value of 1.
wcc(pattern1, pattern2, trwdth, wghts = NULL, acors1 = NULL, acors2 = NULL) wac (pattern1, trwdth, wghts = NULL)
pattern1, pattern2 |
input patterns, typically spectra. Vectors |
trwdth |
triangle width, given in the number of data points |
wghts |
optional weights vector, will be calculated from triangle width if necessary. Sometimes it is more efficient to pre-calculate it and give it as an argument |
acors1, acors2 |
autocorrelations of the input patterns. If not provided, they are calculated |
wcc and wac are defined such that the triangle width stands for
the number of points on one side of and including the current
point. Thus, a trwdth
of 0 signifies a non-existent triangle and
results in an error; a trwdth
equal to 1 only includes the current
point with weight 1 and no neighbouring points.
One number, the weighted autocorrelation or crosscorrelation
Ron Wehrens
de Gelder, R., Wehrens, R. and Hageman, J.A. A generalized expression for the similarity spectra: application to powder diffraction pattern classification. J. Comput. Chem., 22(3), 273-289, 2001.
data(gaschrom) wcc(gaschrom[1,], gaschrom[2,], 20)