calculateZigZagIndex: Calculate the Zig-Zag Index (of a Chromatographic Peak)

In MetaClean: Detection of Low-Quality Peaks in Untargeted Metabolomics Data

Description

Calculates the Zig-Zag Index of the integrated region of a chromatographic peak. The Zig-Zag Index is found by calculating the sum of the slope changes between neighboring points normalized by the average intensity of the peak boundaries.

Usage

calculateZigZagIndex(peakData, pts)

Arguments

peakData	A vector containing characteristic information about a chromatographic peak - including the retention time range
pts	A 2D matrix containing the retention time and intensity values of a chromatographic peak

Details

This function repurposed from Zhang et al. For details, see Zhang, W., & Zhao, P. X. (2014). Quality evaluation of extracted ion chromatograms and chromatographic peaks in liquid chromatography/mass spectrometry-based metabolomics data. BMC Bioinformatics, 15(Suppl 11), S5. https://doi.org/10.1186/1471-2105-15-S11-S5

Value

The Zig-Zag Index value (double)

Examples

# Calculate ZigZag Index for a peak
data(ex_pts)
data(ex_peakData)
zigZagIndex <- calculateZigZagIndex(peakData = ex_peakData, pts = ex_pts)

MetaClean documentation built on Jan. 13, 2021, 6:30 p.m.