%\VignetteIndexEntry{Seurat pbmc_small log normalization example}
\documentclass[11pt, nogin]{article}
\usepackage[noae]{Sweave}
\usepackage[margin=0.75in]{geometry}
\SweaveOpts{keep.source=T}
\title{Application of VAM to Seurat pbmc\_small scRNA-seq data using Seurat log normalization.}
\author{H. Robert Frost}
\begin{document}
\date{}
\setkeys{Gin}{width=1\textwidth} 
\maketitle

\section{Load the VAM package}

<<fig=F, echo=T>>=
library(VAM)
@

\section{Summary statistics for the pbmc\_small scRNA-seq data}

This example uses the pbmc\_small data set included in the SeuratObject package and a single contrived gene set. Please see the other vignettes for more realistic examples using larger scRNA-seq data sets and gene set collections based on MSigDB.

<<fig=F, echo=T>>=
if (requireNamespace("Seurat", quietly=TRUE)) {
	SeuratObject::pbmc_small
	gene.names = rownames(SeuratObject::pbmc_small)
	gene.names[1:5]
	Seurat::VariableFeatures(SeuratObject::pbmc_small)[1:5]
} else {
	message("Seurat package not available! Not executing associated vignette content.")
}	
@

\section{Define gene set collection}

A gene set collection containing just a single contrived set (containing the top 5 variable genes) will be used for this example. 

<<fig=F, echo=T>>=
if (requireNamespace("Seurat", quietly=TRUE)) {
	gene.set.name = "Test"
	gene.ids = c("PPBP", "IGLL5", "VDAC3", "CD1C", "AKR1C3")
	# Create a collection list for this gene set
	gene.set.id.list = list()
	gene.set.id.list[[1]] = gene.ids
	names(gene.set.id.list)[1] = gene.set.name
	gene.set.id.list
	# Create the list of gene indices required by vamForSeurat()
	(gene.set.collection = createGeneSetCollection(gene.ids=gene.names,
		gene.set.collection=gene.set.id.list))
	gene.indices = gene.set.collection[[1]]
(gene.names = gene.names[gene.indices])
} else {
	message("Seurat package not available! Not executing associated vignette content.")
}	
@

\section{Execute VAM method}

Since the scRNA-seq data has been processed using Seurat, we execute VAM using the vamForSeurat() function. We have set return.dist=T so that the squared adjusted Mahalanobis distances will be returned in a "VAMdist" Assay.

<<fig=F, echo=T>>=
if (requireNamespace("Seurat", quietly=TRUE)) {
	pbmc.vam = vamForSeurat(seurat.data=SeuratObject::pbmc_small,
	    gene.set.collection=gene.set.collection,
	    center=F, gamma=T, sample.cov=F, return.dist=T)
} else {
	message("Seurat package not available! Not executing associated vignette content.")
}	
@

Look at the first few entries in the "VAMdist" and "VAMcdf" Assays.

<<fig=F, echo=T>>=
if (requireNamespace("Seurat", quietly=TRUE)) {
	pbmc.vam@assays$VAMdist[1,1:10]
	pbmc.vam@assays$VAMcdf[1,1:10]
} else {
	message("Seurat package not available! Not executing associated vignette content.")
}	
@

\section{Visualize VAM scores}

Visualize VAM scores using Seurat FeaturePlot(). The default Assay must first be changed to "VAMcdf".

<<fig=T, echo=T>>=
if (requireNamespace("Seurat", quietly=TRUE)) {
	Seurat::DefaultAssay(object = pbmc.vam) = "VAMcdf"
	Seurat::FeaturePlot(pbmc.vam, reduction="tsne", features=gene.set.name)
} else {
	message("Seurat package not available! Not executing associated vignette content.")
	par(mar = c(0,0,0,0))
	plot(c(0, 1), c(0, 1), ann = F, bty = 'n', type = 'n', xaxt = 'n', yaxt = 'n')
	text(x = 0.5, y = 0.5,paste("Seurat package not available!\n",
					 "FeaturePlot not generated."),
	cex = 1.6, col = "black")
}	
@

\end{document}