calc.multicoef
(Package: ptw) :
Calculation of warping coefficients when applying more than one
Applying two (or more) warping function after each other can be described with one warping function of a higher warping degree. This function provides the coefficients of this higher degree warping function.
● Data Source:
CranContrib
● Keywords: manip
● Alias: calc.multicoef
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ptw
(Package: ptw) :
Parametric Time Warping
The main functions of the ptw package, performing parametric time warping of one or more samples. Features in the samples are optimally aligned with features in the reference(s). One may align a single sample to a single reference, several samples to a single reference, and several samples to several references. In the latter case, the number of references and samples should be equal. One may require that all samples are warped with the same warping function, or one may allow individual warpings for all samples.
● Data Source:
CranContrib
● Keywords: manip
● Alias: coef.ptw, print.ptw, print.stptw, ptw, stptw, summary.ptw, summary.stptw
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calc.zerocoef
(Package: ptw) :
Correction for warping coefficients when using zeropadding
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.
● Data Source:
CranContrib
● Keywords: manip
● Alias: calc.zerocoef
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wcc
(Package: ptw) :
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.
● Data Source:
CranContrib
● Keywords: manip
● Alias: wac, wac.st, wcc, wcc.st
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plot.ptw
(Package: ptw) :
Plot a ptw object
The function plots a ptw object. It shows either the original and warped signals, or the warping function.
● Data Source:
CranContrib
● Keywords: manip
● Alias: plot.ptw
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predict.ptw
(Package: ptw) :
Prediction of warped signals
Given a ptw object, predict either the signal at a certain warped time, or the warped time itself.
● Data Source:
CranContrib
● Keywords: manip
● Alias: predict.ptw
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baseline.corr
(Package: ptw) :
Baseline Correction using asymmetric least squares
This function estimates a baseline using asymmetric least squares and subtracts it from the data.
● Data Source:
CranContrib
● Keywords: manip
● Alias: baseline.corr
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Function pktab2mzchannel allows to split a list of peaks into several sublists, for instance on the basis of m/z values. The result can be aligned with stptw. The peak list can be obtained from packages like XCMS. The reverse function, mzchannel2pktab, simply gathers all peak positions in one matrix.
● Data Source:
CranContrib
● Keywords: manip
● Alias: mzchannel2pktab, pktab2mzchannel
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difsm
(Package: ptw) :
Smoothing with a finite difference penalty
This function smoothes signals with a finite difference penalty of order 2.
● Data Source:
CranContrib
● Keywords: manip
● Alias: difsm
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For alignment purposes, it may be useful to select traces which show clear features, and to throw away traces that contain mainly noise. This function implements three ways to achieve this: CODA, a criterion similar to varimax, and a criterion based on the highest intensity.
● Data Source:
CranContrib
● Keywords: manip
● Alias: select.traces
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