ptw (version 1.9-17)

calc.zerocoef: Correction for warping coefficients when using zeropadding

Description

This function calculates the warping coefficients for the original range of the data, based on the warping of zero-filled data. Only needed when zeros are added in the beginning of the signal.

Usage

calc.zerocoef(coef, zeros)

Value

a vector containing the corrected warping coefficients

Arguments

coef

vector of warping coefficients of a PTW-calculation on a set of signals with zeros added to the beginning of the signal

zeros

the number of zeros added

Author

Jan Gerretzen

References

Bloemberg, T.G., et al. (2010) "Improved parametric time warping for Proteomics", Chemometrics and Intelligent Laboratory Systems, 104 (1), 65 -- 74.

See Also

padzeros calc.multicoef

Examples

data(gaschrom)
gaschrom.zf <- padzeros(gaschrom, 250)
ref <- gaschrom[1,]
samp <- gaschrom[16,]
ref.zf <- gaschrom.zf[1,]
samp.zf <- gaschrom.zf[16,]
gaschrom.ptw <- ptw(ref.zf, samp.zf)
layout(matrix(1:2,2,1, byrow=TRUE))
plot(gaschrom.ptw)
corr.coef <- calc.zerocoef(gaschrom.ptw$warp.coef, 250)
gaschrom.ptw2 <- ptw(ref, samp, init.coef = corr.coef, try = TRUE)
plot(gaschrom.ptw2)