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ptw (version 1.9-17)

Parametric Time Warping

Description

Parametric Time Warping aligns patterns, i.e., it aims to put corresponding features at the same locations. The algorithm searches for an optimal polynomial describing the warping. It is possible to align one sample to a reference, several samples to the same reference, or several samples to several references. One can choose between calculating individual warpings, or one global warping for a set of samples and one reference. Two optimization criteria are implemented: RMS (Root Mean Square error) and WCC (Weighted Cross Correlation). Both warping of peak profiles and of peak lists are supported. A vignette for the latter is contained in the inst/doc directory of the source package - the vignette source can be found on the package github site. See `citation("ptw")` for more details.

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Install

install.packages('ptw')

Monthly Downloads

1,892

Version

1.9-17

License

GPL (>= 2)

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Maintainer

Ron Wehrens

Last Published

January 22nd, 2026

Functions in ptw (1.9-17)

mzchannel2pktab

Conversion between peak lists from hyphenated MS (LCMS, GCMS, ...) data and input for stptw
warp.time

Transform time according to a given warping function
wcc

Weighted auto- and cross-correlation measures
ptwgrid

Calculate RMS or WCC values on a grid
ptw-package

ptw: Parametric Time Warping
plot.ptw

Plot a ptw object
ptw

Parametric Time Warping
predict.ptw

Prediction of warped signals
padzeros

Pad matrix with zeros
select.traces

Select traces from a data set according to several criteria
whit1

Weighted Whittaker smoothing with a first order finite difference penalty
whit2

Weighted Whittaker smoothing with a second order finite difference penalty
difsm

Smoothing with a finite difference penalty
RMS

Quality criteria for comparing patterns with shifts
coda

Chromatogram selection using the CODA algorithm
asysm

Trend estimation with asymmetric least squares
lcms

Parts of 3 proteomic LC-MS samples
gaschrom

16 calibration GC traces
baseline.corr

Baseline Correction using asymmetric least squares
calc.multicoef

Calculation of warping coefficients when applying more than one warping function successively
calc.zerocoef

Correction for warping coefficients when using zeropadding
bestref

Identification of optimal reference