msSmoothApprox: Piecewise Linear Baseline Estimation

In zeehio/msProcess: Protein Mass Spectra Processing

Description

Estimates the baseline of a spectrum as a linear or constant interpolation of the local minima of a spectrum.

Usage

msSmoothApprox(x, y, method="linear", rule=2, f=0.5,
    index=rep(TRUE, length(x)), process="msSmoothApprox")

Arguments

x	A numeric vector representing the m/z values of a spectrum.
y	A numeric vector representing the intensity values of the spectrum corresponding to the specified m/z values.
f	A numeric scalar used when method="constant", which determines a blend of the left and right side y values. e.g., suppose we want an interpolated value between x1 and x2 (with corresponding y values y1 and y2). Then the interpolated value is (1-f)*y1+f*y2. Thus, if f=0, the left y-value is used, if f=1, the right y-value, and if f is between 0 and 1, an intermediate value is used. Default: 0.5.
index	A logical vector indicating the local minima to be used to approximate the baseline. Default: rep(TRUE, length(x)).
method	A character string describing the method to be used in approximating the baseline. This must be either "linear" or "constant". Default: "linear".
process	A character string denoting the name of the process to register with the (embedded) event history object of the input after processing the input data. Default: "msSmoothApprox".
rule	An integer (either 2 or 3) describing the rule to be used for values that are outside the range of the minima of x. If rule=2, the y values corresponding to the extreme x values will be used. If rule=3, linear extrapolation is used. Default: 2.

Value

A numeric vector representing the estimated piece-wise linear baseline.

See Also

msSmoothKsmooth, msSmoothLoess, msSmoothMean, msSmoothMonotone, msSmoothSpline, msSmoothSupsmu.

zeehio/msProcess documentation built on May 4, 2019, 10:15 p.m.