Biopeak (version 1.0)

findPeaks: Identification of peaks in an expression signal

Description

This helper function identifies peaks in an expression signal by treating the gene expression as a signal that propagates along an experimental axis. A peak is defined as a local maximum in the expression signal satisfying: y(t) > y(t+1) and y(t) > y(t-1), where y(t) represents the gene expression as a function of series condition t.

Usage

findPeaks(expr)

Arguments

expr

A numeric vector with gene expression values

Value

Returns a list comprising of a numeric vector with the location of each peak (peakloc), a numeric vector with the absolute height of each peak (peakheight) and a character vector of gene symbols for which at least one peak has been identified (peakgenes).

Examples

# NOT RUN {
# Example based on the heat-shock dataset
data(heat)
heat = as.matrix(heat)
# Run the findPeaks function for the first gene in the expression matrix
peaks <- findPeaks(heat[1,])

# }