| attachSegments {mQTL} | R Documentation |
Concatenation of test and reference segments to ensure one-to-one correspondence.
attachSegments(refSegments,testSegments)
refSegments |
segments of the reference spectrum |
testSegments |
segments of the test spectrum |
The algorithm:
For each reference segment within segment boundaries, i.e. between initial and final positions, find all centre (middle) positions of test segments and merge those segments, if more than one centre position is found
Apply the same procedure for each test segment
A list:
segments$start |
start of each concatenated test segment |
segments$PeakLeftBoundary |
peak left boundary of each concatenated test segment |
segments$PeakRightBoundary |
peak right boundary of each concatenated test segment |
segments$Peaks |
peaks of each concatenated test segment |
segments$end |
end of each concatenated test segment |
segments$end |
center of each concatenated test segment |
Lyamine Hedjazi
Veselkov,K. et al (2009) Recursive Segment-Wise Peak Alignment of Biological 1H NMR Spectra for Improved Metabolic Biomarker Recovery, Anal. Chem., 81(1), 56-66.
## Not run: ## Data Sp=matrix(rnorm(10*13454,mean=0,sd=1), nrow=10,ncol=13454) ##Segmentation parameters peakParam=list() peakParam$ppmDist <- 0.03# (ppm) # distance to concatenate adjacent peaks #default 0.03# peakParam$ampThr <- 0.3 # amplitude value to threshold small peaks # peakParam$minPeakWidth <- 0.005 #min peak width in ppm scale peakParam$iFrameLen<-11 #Savitzky-Golay frame length in ppm scale peakParam$iOrder<-3 #polynomial order of Savitzky - Golay filter peakParam$peakEdgeMax<-0.2 ##Reference spectrum selection step<-0.02 # Recursion step (default 0.02) index<-selectRefSp(Sp,step) refSp<-Sp[index,] #segmentate a reference spectrum refSegments<- segmentateSp(refSp, peakParam) # segmentate reference spectrum #segmentate a test spectrum spectrum<-Sp[10,] testSegments<- segmentateSp(spectrum, peakParam) # segmentate test spectrum (10th sample) # match test and reference segments attachedSegs<-attachSegments(refSegments,testSegments) ## End(Not run)