diff limma_voom.R @ 0:bdebdea5f6a7 draft

planemo upload for repository https://github.com/galaxyproject/tools-iuc/tree/master/tools/limma_voom commit 2f34a215c35f08c3666f314a87d235437baa1d21
author iuc
date Mon, 12 Jun 2017 07:41:02 -0400
parents
children 76d01fe0ec36
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/limma_voom.R	Mon Jun 12 07:41:02 2017 -0400
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+# This tool takes in a matrix of feature counts as well as gene annotations and
+# outputs a table of top expressions as well as various plots for differential
+# expression analysis
+#
+# ARGS: 1.countPath       -Path to RData input containing counts
+#       2.annoPath        -Path to RData input containing gene annotations
+#       3.htmlPath        -Path to html file linking to other outputs
+#       4.outPath         -Path to folder to write all output to
+#       5.rdaOpt          -String specifying if RData should be saved
+#       6.normOpt         -String specifying type of normalisation used
+#       7.weightOpt       -String specifying usage of weights
+#       8.contrastData    -String containing contrasts of interest
+#       9.cpmReq          -Float specifying cpm requirement
+#       10.sampleReq      -Integer specifying cpm requirement
+#       11.pAdjOpt        -String specifying the p-value adjustment method
+#       12.pValReq        -Float specifying the p-value requirement
+#       13.lfcReq         -Float specifying the log-fold-change requirement
+#       14.factorData     -String containing factor names and values
+#
+# OUT:  Voom Plot
+#       BCV Plot
+#       MA Plot
+#       Top Expression Table
+#       HTML file linking to the ouputs
+#
+# Author: Shian Su - registertonysu@gmail.com - Jan 2014
+
+# Record starting time
+timeStart <- as.character(Sys.time())
+
+# Load all required libraries
+library(methods, quietly=TRUE, warn.conflicts=FALSE)
+library(statmod, quietly=TRUE, warn.conflicts=FALSE)
+library(splines, quietly=TRUE, warn.conflicts=FALSE)
+library(edgeR, quietly=TRUE, warn.conflicts=FALSE)
+library(limma, quietly=TRUE, warn.conflicts=FALSE)
+library(scales, quietly=TRUE, warn.conflicts=FALSE)
+
+if (packageVersion("limma") < "3.20.1") {
+  stop("Please update 'limma' to version >= 3.20.1 to run this tool")
+}
+
+################################################################################
+### Function Delcaration
+################################################################################
+# Function to sanitise contrast equations so there are no whitespaces
+# surrounding the arithmetic operators, leading or trailing whitespace
+sanitiseEquation <- function(equation) {
+  equation <- gsub(" *[+] *", "+", equation)
+  equation <- gsub(" *[-] *", "-", equation)
+  equation <- gsub(" *[/] *", "/", equation)
+  equation <- gsub(" *[*] *", "*", equation)
+  equation <- gsub("^\\s+|\\s+$", "", equation)
+  return(equation)
+}
+
+# Function to sanitise group information
+sanitiseGroups <- function(string) {
+  string <- gsub(" *[,] *", ",", string)
+  string <- gsub("^\\s+|\\s+$", "", string)
+  return(string)
+}
+
+# Function to change periods to whitespace in a string
+unmake.names <- function(string) {
+  string <- gsub(".", " ", string, fixed=TRUE)
+  return(string)
+}
+
+# Generate output folder and paths
+makeOut <- function(filename) {
+  return(paste0(outPath, "/", filename))
+}
+
+# Generating design information
+pasteListName <- function(string) {
+  return(paste0("factors$", string))
+}
+
+# Create cata function: default path set, default seperator empty and appending
+# true by default (Ripped straight from the cat function with altered argument
+# defaults)
+cata <- function(..., file = htmlPath, sep = "", fill = FALSE, labels = NULL, 
+                 append = TRUE) {
+  if (is.character(file)) 
+    if (file == "") 
+      file <- stdout()
+  else if (substring(file, 1L, 1L) == "|") {
+    file <- pipe(substring(file, 2L), "w")
+    on.exit(close(file))
+  }
+  else {
+    file <- file(file, ifelse(append, "a", "w"))
+    on.exit(close(file))
+  }
+  .Internal(cat(list(...), file, sep, fill, labels, append))
+}
+
+# Function to write code for html head and title
+HtmlHead <- function(title) {
+  cata("<head>\n")
+  cata("<title>", title, "</title>\n")
+  cata("</head>\n")
+}
+
+# Function to write code for html links
+HtmlLink <- function(address, label=address) {
+  cata("<a href=\"", address, "\" target=\"_blank\">", label, "</a><br />\n")
+}
+
+# Function to write code for html images
+HtmlImage <- function(source, label=source, height=600, width=600) {
+  cata("<img src=\"", source, "\" alt=\"", label, "\" height=\"", height)
+  cata("\" width=\"", width, "\"/>\n")
+}
+
+# Function to write code for html list items
+ListItem <- function(...) {
+  cata("<li>", ..., "</li>\n")
+}
+
+TableItem <- function(...) {
+  cata("<td>", ..., "</td>\n")
+}
+
+TableHeadItem <- function(...) {
+  cata("<th>", ..., "</th>\n")
+}
+
+################################################################################
+### Input Processing
+################################################################################
+
+# Collects arguments from command line
+argv <- commandArgs(TRUE)
+
+# Grab arguments
+countPath <- as.character(argv[1])
+annoPath <- as.character(argv[2])
+htmlPath <- as.character(argv[3])
+outPath <- as.character(argv[4])
+rdaOpt <- as.character(argv[5])
+normOpt <- as.character(argv[6])
+weightOpt <- as.character(argv[7])
+contrastData <- as.character(argv[8])
+cpmReq <- as.numeric(argv[9])
+sampleReq <- as.numeric(argv[10])
+pAdjOpt <- as.character(argv[11])
+pValReq <- as.numeric(argv[12])
+lfcReq <- as.numeric(argv[13])
+factorData <- list()
+for (i in 14:length(argv)) {
+  newFact <- unlist(strsplit(as.character(argv[i]), split="::"))
+  factorData <- rbind(factorData, newFact)
+} # Factors have the form: FACT_NAME::LEVEL,LEVEL,LEVEL,LEVEL,...
+
+# Process arguments
+if (weightOpt=="yes") {
+  wantWeight <- TRUE
+} else {
+  wantWeight <- FALSE
+}
+
+if (rdaOpt=="yes") {
+  wantRda <- TRUE
+} else {
+  wantRda <- FALSE
+}
+
+if (annoPath=="None") {
+  haveAnno <- FALSE
+} else {
+  haveAnno <- TRUE
+}
+
+# Set the row names to be the name of the factor and delete first row
+row.names(factorData) <- factorData[, 1]
+factorData <- factorData[, -1]
+factorData <- sapply(factorData, sanitiseGroups)
+factorData <- sapply(factorData, strsplit, split=",")
+factorData <- sapply(factorData, make.names)
+
+# Transform factor data into data frame of R factor objects
+factors <- data.frame(factorData)
+
+#Create output directory
+dir.create(outPath, showWarnings=FALSE)
+
+# Split up contrasts seperated by comma into a vector then sanitise
+contrastData <- unlist(strsplit(contrastData, split=","))
+contrastData <- sanitiseEquation(contrastData)
+contrastData <- gsub(" ", ".", contrastData, fixed=TRUE)
+
+bcvOutPdf <- makeOut("bcvplot.pdf")
+bcvOutPng <- makeOut("bcvplot.png")
+mdsOutPdf <- makeOut("mdsplot.pdf")
+mdsOutPng <- makeOut("mdsplot.png")
+voomOutPdf <- makeOut("voomplot.pdf")
+voomOutPng <- makeOut("voomplot.png") 
+maOutPdf <- character()   # Initialise character vector
+maOutPng <- character()
+topOut <- character()
+for (i in 1:length(contrastData)) {
+  maOutPdf[i] <- makeOut(paste0("maplot_", contrastData[i], ".pdf"))
+  maOutPng[i] <- makeOut(paste0("maplot_", contrastData[i], ".png"))
+  topOut[i] <- makeOut(paste0("limma-voom_", contrastData[i], ".tsv"))
+}                         # Save output paths for each contrast as vectors
+rdaOut <- makeOut("RData.rda")
+sessionOut <- makeOut("session_info.txt")
+
+# Initialise data for html links and images, data frame with columns Label and 
+# Link
+linkData <- data.frame(Label=character(), Link=character(),
+                       stringsAsFactors=FALSE)
+imageData <- data.frame(Label=character(), Link=character(),
+                        stringsAsFactors=FALSE)
+
+# Initialise vectors for storage of up/down/neutral regulated counts
+upCount <- numeric()
+downCount <- numeric()
+flatCount <- numeric()
+                        
+# Read in counts and geneanno data
+counts <- read.table(countPath, header=TRUE, sep="\t")
+row.names(counts) <- counts[, 1]
+counts <- counts[ , -1]
+countsRows <- nrow(counts)
+if (haveAnno) {
+  geneanno <- read.table(annoPath, header=TRUE, sep="\t")
+}
+
+################################################################################
+### Data Processing
+################################################################################
+
+# Extract counts and annotation data
+data <- list()
+data$counts <- counts
+if (haveAnno) {
+  data$genes <- geneanno
+} else {
+  data$genes <- data.frame(GeneID=row.names(counts))
+}
+
+# Filter out genes that do not have a required cpm in a required number of
+# samples
+preFilterCount <- nrow(data$counts)
+sel <- rowSums(cpm(data$counts) > cpmReq) >= sampleReq
+data$counts <- data$counts[sel, ]
+data$genes <- data$genes[sel, ]
+postFilterCount <- nrow(data$counts)
+filteredCount <- preFilterCount-postFilterCount
+
+# Creating naming data
+samplenames <- colnames(data$counts)
+sampleanno <- data.frame("sampleID"=samplenames, factors)
+
+# Generating the DGEList object "data"
+data$samples <- sampleanno
+data$samples$lib.size <- colSums(data$counts)
+data$samples$norm.factors <- 1
+row.names(data$samples) <- colnames(data$counts)
+data <- new("DGEList", data)
+
+factorList <- sapply(names(factors), pasteListName)
+formula <- "~0"
+for (i in 1:length(factorList)) {
+  formula <- paste(formula, factorList[i], sep="+")
+}
+formula <- formula(formula)
+design <- model.matrix(formula)
+for (i in 1:length(factorList)) {
+  colnames(design) <- gsub(factorList[i], "", colnames(design), fixed=TRUE)
+}
+
+# Calculating normalising factor, estimating dispersion
+data <- calcNormFactors(data, method=normOpt)
+#data <- estimateDisp(data, design=design, robust=TRUE)
+
+# Generate contrasts information
+contrasts <- makeContrasts(contrasts=contrastData, levels=design)
+
+# Name rows of factors according to their sample
+row.names(factors) <- names(data$counts)
+
+################################################################################
+### Data Output
+################################################################################
+
+# BCV Plot
+#png(bcvOutPng, width=600, height=600)
+#plotBCV(data, main="BCV Plot")
+#imageData[1, ] <- c("BCV Plot", "bcvplot.png")
+#invisible(dev.off())
+
+#pdf(bcvOutPdf)
+#plotBCV(data, main="BCV Plot")
+#invisible(dev.off())
+
+if (wantWeight) {
+  # Creating voom data object and plot
+  png(voomOutPng, width=1000, height=600)
+  vData <- voomWithQualityWeights(data, design=design, plot=TRUE)
+  imageData[1, ] <- c("Voom Plot", "voomplot.png")
+  invisible(dev.off())
+  
+  pdf(voomOutPdf, width=14)
+  vData <- voomWithQualityWeights(data, design=design, plot=TRUE)
+  linkData[1, ] <- c("Voom Plot (.pdf)", "voomplot.pdf")
+  invisible(dev.off())
+  
+  # Generating fit data and top table with weights
+  wts <- vData$weights
+  voomFit <- lmFit(vData, design, weights=wts)
+  
+} else {
+  # Creating voom data object and plot
+  png(voomOutPng, width=600, height=600)
+  vData <- voom(data, design=design, plot=TRUE)
+  imageData[1, ] <- c("Voom Plot", "voomplot.png")
+  invisible(dev.off())
+  
+  pdf(voomOutPdf)
+  vData <- voom(data, design=design, plot=TRUE)
+  linkData[1, ] <- c("Voom Plot (.pdf)", "voomplot.pdf")
+  invisible(dev.off())
+  
+  # Generate voom fit
+  voomFit <- lmFit(vData, design)
+  
+}
+
+# Fit linear model and estimate dispersion with eBayes
+voomFit <- contrasts.fit(voomFit, contrasts)
+voomFit <- eBayes(voomFit)
+
+# Plot MDS
+labels <- names(counts)
+png(mdsOutPng, width=600, height=600)
+# Currently only using a single factor
+plotMDS(vData, labels=labels, col=as.numeric(factors[, 1]), cex=0.8)
+imgName <- "Voom Plot"
+imgAddr <- "mdsplot.png"
+imageData <- rbind(imageData, c(imgName, imgAddr))
+invisible(dev.off())
+
+pdf(mdsOutPdf)
+plotMDS(vData, labels=labels, cex=0.5)
+linkName <- paste0("MDS Plot (.pdf)")
+linkAddr <- paste0("mdsplot.pdf")
+linkData <- rbind(linkData, c(linkName, linkAddr))
+invisible(dev.off())
+
+
+for (i in 1:length(contrastData)) {
+
+  status = decideTests(voomFit[, i], adjust.method=pAdjOpt, p.value=pValReq,
+                       lfc=lfcReq)
+                       
+  sumStatus <- summary(status)
+  
+  # Collect counts for differential expression
+  upCount[i] <- sumStatus["1",]
+  downCount[i] <- sumStatus["-1",]
+  flatCount[i] <- sumStatus["0",]
+                       
+  # Write top expressions table
+  top <- topTable(voomFit, coef=i, number=Inf, sort.by="P")
+  write.table(top, file=topOut[i], row.names=FALSE, sep="\t")
+  
+  linkName <- paste0("limma-voom_", contrastData[i], 
+                     ".tsv")
+  linkAddr <- paste0("limma-voom_", contrastData[i], ".tsv")
+  linkData <- rbind(linkData, c(linkName, linkAddr))
+  
+  # Plot MA (log ratios vs mean average) using limma package on weighted data
+  pdf(maOutPdf[i])
+  limma::plotMA(voomFit, status=status, coef=i,
+                main=paste("MA Plot:", unmake.names(contrastData[i])), 
+                col=alpha(c("firebrick", "blue"), 0.4), values=c("1", "-1"),
+                xlab="Average Expression", ylab="logFC")
+  
+  abline(h=0, col="grey", lty=2)
+  
+  linkName <- paste0("MA Plot_", contrastData[i], " (.pdf)")
+  linkAddr <- paste0("maplot_", contrastData[i], ".pdf")
+  linkData <- rbind(linkData, c(linkName, linkAddr))
+  invisible(dev.off())
+  
+  png(maOutPng[i], height=600, width=600)
+  limma::plotMA(voomFit, status=status, coef=i,
+                main=paste("MA Plot:", unmake.names(contrastData[i])), 
+                col=alpha(c("firebrick", "blue"), 0.4), values=c("1", "-1"),
+                xlab="Average Expression", ylab="logFC")
+  
+  abline(h=0, col="grey", lty=2)
+  
+  imgName <- paste0("MA Plot_", contrastData[i])
+  imgAddr <- paste0("maplot_", contrastData[i], ".png")
+  imageData <- rbind(imageData, c(imgName, imgAddr))
+  invisible(dev.off())
+}
+sigDiff <- data.frame(Up=upCount, Flat=flatCount, Down=downCount)
+row.names(sigDiff) <- contrastData
+
+# Save relevant items as rda object
+if (wantRda) {
+  if (wantWeight) {
+    save(data, status, vData, labels, factors, wts, voomFit, top, contrasts, 
+         design,
+         file=rdaOut, ascii=TRUE)
+  } else {
+    save(data, status, vData, labels, factors, voomFit, top, contrasts, design,
+         file=rdaOut, ascii=TRUE)
+  }
+  linkData <- rbind(linkData, c("RData (.rda)", "RData.rda"))
+}
+
+# Record session info
+writeLines(capture.output(sessionInfo()), sessionOut)
+linkData <- rbind(linkData, c("Session Info", "session_info.txt"))
+
+# Record ending time and calculate total run time
+timeEnd <- as.character(Sys.time())
+timeTaken <- capture.output(round(difftime(timeEnd,timeStart), digits=3))
+timeTaken <- gsub("Time difference of ", "", timeTaken, fixed=TRUE)
+################################################################################
+### HTML Generation
+################################################################################
+
+# Clear file
+cat("", file=htmlPath)
+
+cata("<html>\n")
+
+cata("<body>\n")
+cata("<h3>Limma-voom Analysis Output:</h3>\n")
+cata("PDF copies of JPEGS available in 'Plots' section.<br />\n")
+if (wantWeight) {
+  HtmlImage(imageData$Link[1], imageData$Label[1], width=1000)
+} else {
+  HtmlImage(imageData$Link[1], imageData$Label[1])
+}
+
+for (i in 2:nrow(imageData)) {
+  HtmlImage(imageData$Link[i], imageData$Label[i])
+}
+
+cata("<h4>Differential Expression Counts:</h4>\n")
+
+cata("<table border=\"1\" cellpadding=\"4\">\n")
+cata("<tr>\n")
+TableItem()
+for (i in colnames(sigDiff)) {
+  TableHeadItem(i)
+}
+cata("</tr>\n")
+for (i in 1:nrow(sigDiff)) {
+  cata("<tr>\n")
+  TableHeadItem(unmake.names(row.names(sigDiff)[i]))
+  for (j in 1:ncol(sigDiff)) {
+    TableItem(as.character(sigDiff[i, j]))
+  }
+  cata("</tr>\n")
+}
+cata("</table>")
+
+cata("<h4>Plots:</h4>\n")
+for (i in 1:nrow(linkData)) {
+  if (grepl(".pdf", linkData$Link[i])) {
+    HtmlLink(linkData$Link[i], linkData$Label[i])
+  }
+}
+
+cata("<h4>Tables:</h4>\n")
+for (i in 1:nrow(linkData)) {
+  if (grepl(".tsv", linkData$Link[i])) {
+    HtmlLink(linkData$Link[i], linkData$Label[i])
+  }
+}
+
+if (wantRda) {
+  cata("<h4>R Data Object:</h4>\n")
+  for (i in 1:nrow(linkData)) {
+    if (grepl(".rda", linkData$Link[i])) {
+      HtmlLink(linkData$Link[i], linkData$Label[i])
+    }
+  }
+}
+
+cata("<p>Alt-click links to download file.</p>\n")
+cata("<p>Click floppy disc icon associated history item to download ")
+cata("all files.</p>\n")
+cata("<p>.tsv files can be viewed in Excel or any spreadsheet program.</p>\n")
+
+cata("<h4>Additional Information</h4>\n")
+cata("<ul>\n")
+if (cpmReq!=0 && sampleReq!=0) {
+  tempStr <- paste("Genes without more than", cpmReq,
+                   "CPM in at least", sampleReq, "samples are insignificant",
+                   "and filtered out.")
+  ListItem(tempStr)
+  filterProp <- round(filteredCount/preFilterCount*100, digits=2)
+  tempStr <- paste0(filteredCount, " of ", preFilterCount," (", filterProp,
+                   "%) genes were filtered out for low expression.")
+  ListItem(tempStr)
+}
+ListItem(normOpt, " was the method used to normalise library sizes.")
+if (wantWeight) {
+  ListItem("Weights were applied to samples.")
+} else {
+  ListItem("Weights were not applied to samples.")
+}
+if (pAdjOpt!="none") {
+  if (pAdjOpt=="BH" || pAdjOpt=="BY") {
+    tempStr <- paste0("MA-Plot highlighted genes are significant at FDR ",
+                      "of ", pValReq," and exhibit log2-fold-change of at ", 
+                      "least ", lfcReq, ".")
+    ListItem(tempStr)
+  } else if (pAdjOpt=="holm") {
+    tempStr <- paste0("MA-Plot highlighted genes are significant at adjusted ",
+                      "p-value of ", pValReq,"  by the Holm(1979) ",
+                      "method, and exhibit log2-fold-change of at least ", 
+                      lfcReq, ".")
+    ListItem(tempStr)
+  }
+} else {
+  tempStr <- paste0("MA-Plot highlighted genes are significant at p-value ",
+                    "of ", pValReq," and exhibit log2-fold-change of at ", 
+                    "least ", lfcReq, ".")
+  ListItem(tempStr)
+}
+cata("</ul>\n")
+
+cata("<h4>Summary of experimental data:</h4>\n")
+
+cata("<p>*CHECK THAT SAMPLES ARE ASSOCIATED WITH CORRECT GROUP*</p>\n")
+
+cata("<table border=\"1\" cellpadding=\"3\">\n")
+cata("<tr>\n")
+TableItem()
+for (i in names(factors)) {
+  TableHeadItem(i)
+}
+cata("</tr>\n")
+
+for (i in 1:nrow(factors)) {
+  cata("<tr>\n")
+  TableHeadItem(row.names(factors)[i])
+  for (j in ncol(factors)) {
+    TableItem(as.character(unmake.names(factors[i, j])))
+  }
+  cata("</tr>\n")
+}
+cata("</table>")
+
+cit <- character()
+link <- character()
+link[1] <- paste0("<a href=\"",
+                  "http://www.bioconductor.org/packages/release/bioc/",
+                  "vignettes/limma/inst/doc/usersguide.pdf",
+                  "\">", "limma User's Guide", "</a>.")
+
+link[2] <- paste0("<a href=\"",
+                  "http://www.bioconductor.org/packages/release/bioc/",
+                  "vignettes/edgeR/inst/doc/edgeRUsersGuide.pdf",
+                  "\">", "edgeR User's Guide", "</a>")
+
+cit[1] <- paste("Please cite the following paper for this tool:")
+
+cit[2] <- paste("Liu R, Holik AZ, Su S, Jansz N, Chen K, Leong HS, Blewitt ME,",
+                "Asselin-Labat ML, Smyth GK, Ritchie ME (2015). Why weight? ",
+                "Modelling sample and observational level variability improves power ",
+                "in RNA-seq analyses. Nucleic Acids Research, 43(15), e97.")
+
+cit[3] <- paste("Please cite the paper below for the limma software itself.",
+                "Please also try to cite the appropriate methodology articles",
+                "that describe the statistical methods implemented in limma,",
+                "depending on which limma functions you are using. The",
+                "methodology articles are listed in Section 2.1 of the",
+                link[1],
+                "Cite no. 3 only if sample weights were used.")
+cit[4] <- paste("Smyth GK (2005). Limma: linear models for microarray data.",
+                "In: 'Bioinformatics and Computational Biology Solutions using",
+                "R and Bioconductor'. R. Gentleman, V. Carey, S. doit,.",
+                "Irizarry, W. Huber (eds), Springer, New York, pages 397-420.")
+cit[5] <- paste("Please cite the first paper for the software itself and the",
+                "other papers for the various original statistical methods",
+                "implemented in edgeR.  See Section 1.2 in the", link[2],
+                "for more detail.")
+cit[6] <- paste("Robinson MD, McCarthy DJ and Smyth GK (2010). edgeR: a",
+                "Bioconductor package for differential expression analysis",
+                "of digital gene expression data. Bioinformatics 26, 139-140")
+cit[7] <- paste("Robinson MD and Smyth GK (2007). Moderated statistical tests",
+                "for assessing differences in tag abundance. Bioinformatics",
+                "23, 2881-2887")
+cit[8] <- paste("Robinson MD and Smyth GK (2008). Small-sample estimation of",
+                "negative binomial dispersion, with applications to SAGE data.",
+                "Biostatistics, 9, 321-332")
+cit[9] <- paste("McCarthy DJ, Chen Y and Smyth GK (2012). Differential",
+                "expression analysis of multifactor RNA-Seq experiments with",
+                "respect to biological variation. Nucleic Acids Research 40,",
+                "4288-4297")
+cit[10] <- paste("Law CW, Chen Y, Shi W, and Smyth GK (2014). Voom:",
+                "precision weights unlock linear model analysis tools for",
+                "RNA-seq read counts. Genome Biology 15, R29.")
+cit[11] <- paste("Ritchie ME, Diyagama D, Neilson J, van Laar R,", 
+                "Dobrovic A, Holloway A and Smyth GK (2006).",
+                "Empirical array quality weights for microarray data.",
+                "BMC Bioinformatics 7, Article 261.")
+cata("<h3>Citations</h3>\n")
+cata(cit[1], "\n")
+cata("<br>\n")
+cata(cit[2], "\n")
+
+cata("<h4>limma</h4>\n")
+cata(cit[3], "\n")
+cata("<ol>\n")
+ListItem(cit[4])
+ListItem(cit[10])
+ListItem(cit[11])
+cata("</ol>\n")
+
+cata("<h4>edgeR</h4>\n")
+cata(cit[5], "\n")
+cata("<ol>\n")
+ListItem(cit[6])
+ListItem(cit[7])
+ListItem(cit[8])
+ListItem(cit[9])
+cata("</ol>\n")
+
+cata("<p>Please report problems or suggestions to: su.s@wehi.edu.au</p>\n")
+
+for (i in 1:nrow(linkData)) {
+  if (grepl("session_info", linkData$Link[i])) {
+    HtmlLink(linkData$Link[i], linkData$Label[i])
+  }
+}
+
+cata("<table border=\"0\">\n")
+cata("<tr>\n")
+TableItem("Task started at:"); TableItem(timeStart)
+cata("</tr>\n")
+cata("<tr>\n")
+TableItem("Task ended at:"); TableItem(timeEnd)
+cata("</tr>\n")
+cata("<tr>\n")
+TableItem("Task run time:"); TableItem(timeTaken)
+cata("<tr>\n")
+cata("</table>\n")
+
+cata("</body>\n")
+cata("</html>")