R/PoisBG.R
In Nanostring-Biostats/GeoDiff: Count model based differential expression and normalization on GeoMx RNA data
#' Estimate Poisson background model for either single slide or multiple slides
#'
#' Estimate Poisson background model for either single slide or multiple slides
#'
#' @param object a valid GeoMx S4 object
#' @param groupvar the group variable name for slide
#' @param iterations maximum iterations to be run, default=10
#' @param tol tolerance to determine convergence, default = 1e-3
#' @param size_scale method to scale the sizefact, sum(sizefact)=1 when size_scale="sum", sizefact[1]=1 when size_scale="first"
#' @param ... additional argument list that might be used
#'
#' @importFrom Biobase exprs
#' @importFrom Biobase fData
#' @importFrom Biobase sampleNames
#' @importFrom Biobase featureNames
#'
#' @return a valid GeoMx S4 object if split is FALSE
#' \itemize{
#' \item sizefact - estimated size factor in phenoData
#' \item featfact - estimated feature factor in featureData
#' }
#'
#' a valid GeoMx S4 object if split is TRUE,
#' \itemize{
#' \item sizefact - estimated size factor in phenoData
#' \item featfact_XX - estimated feature factor vector, column name (denoted as XX) the same as the slide id, in featureData for each unique slide
#' \item fitPoisBG_sp_var - the column name for slide, in experimentData
#' }
#'
#' @examples
#'
#' data(demoData)
#' demoData <- fitPoisBG(demoData, size_scale = "sum")
#' data(demoData)
#' demoData <- fitPoisBG(demoData, groupvar = "slide name", size_scale = "sum")
#' @export
#' @docType methods
#' @rdname fitPoisBG-methods
setGeneric("fitPoisBG",
signature = c("object"),
function(object, ...) standardGeneric("fitPoisBG")
)
#' @rdname fitPoisBG-methods
#' @aliases fitPoisBG,NanoStringGeoMxSet-method
setMethod(
"fitPoisBG", "NanoStringGeoMxSet",
function(object, groupvar = NULL, iterations = 10, tol = 1e-3, size_scale = c("sum", "first"), ...) {
# check on tol
tol <- as.double(tol)
stopifnot(length(tol) == 1)
stopifnot(tol >= 0)
# extract the negative probes matrix
negdat <- object[which(Biobase::fData(object)$CodeClass == "Negative"), ]
countmat <- Biobase::exprs(negdat)
if (is.null(groupvar)) {
# fit the model as a single slide
split <- FALSE
} else if (!(groupvar %in% varLabels(object))) {
stop(sprintf("%s is not found in the S4 object.", groupvar))
} else {
# extract the groupvar
id <- object[[groupvar]]
if (length(unique(id)) == 1) {
# this is equivalent as fitting the model as a single slide
split <- FALSE
warning(sprintf("`%s` has only one value, %s", groupvar, unique(id)))
} else {
# fit the model for multiple slides
split <- TRUE
}
}
if (isFALSE(split)) {
# calling the fitPoisBG function when split is FALSE
result <- fitPoisBG(
object = countmat,
iterations = iterations,
tol = tol,
size_scale = size_scale
)
object[["sizefact"]] <- result$sizefact[Biobase::sampleNames(object)]
Biobase::fData(object)[["featfact"]] <- NA
Biobase::fData(object)[["featfact"]][match(names(result$featfact), Biobase::featureNames(object), nomatch = 0)] <- result$featfact
} else {
# calling the fitPoisBG_sp function when split is TRUE
result <- fitPoisBG_sp(
object = countmat,
id = id,
iterations = iterations,
tol = tol,
size_scale = size_scale
)
# append results to the object
object[["sizefact_sp"]] <- result$sizefact[Biobase::sampleNames(object)]
for (index in unique(result$id)) {
Biobase::fData(object)[[paste0("featfact_", index)]] <- NA
Biobase::fData(object)[[paste0("featfact_", index)]][match(rownames(result$featfact), Biobase::featureNames(object), nomatch = 0)] <- result$featfact[, index]
}
Biobase::notes(object)$fitPoisBG_sp_var <- groupvar
}
return(object)
}
)
#' Estimate Poisson background model
#'
#' Estimate Poisson background model:
#'
#' @param object count matrix with features in rows and samples in columns
#' @param iterations maximum iterations to be run, default=10
#' @param tol tolerance to determine convergence, default = 1e-3
#' @param size_scale method to scale the sizefact, sum(sizefact)=1 when size_scale="sum", sizefact[1]=1 when size_scale="first"
#'
#' @return a list of following items
#' \itemize{
#' \item sizefact - estimated size factor
#' \item featfact - estimated feature factor
#' \item countmat - the input count matrix
#' }
#'
#' @rdname fitPoisBG-methods
#' @aliases fitPoisBG,matrix-method
setMethod(
"fitPoisBG", "matrix",
function(object, iterations = 10, tol = 1e-3, size_scale = c("sum", "first")) {
size_scale <- match.arg(size_scale)
n_feature <- NROW(object)
n_sample <- NCOL(object)
ind_na <- which(is.na(object), arr.ind = TRUE)
featfact0 <- numeric(n_feature)
sizefact <- apply(object, 2, mean, na.rm = TRUE)
if (size_scale == "first") {
scale_fac <- sizefact[1]
} else if (size_scale == "sum") {
scale_fac <- sum(sizefact)
}
sizefact <- sizefact / scale_fac
sizefact0 <- sizefact
sizefact_mat <- matrix(rep(sizefact, n_feature), n_feature, n_sample, byrow = TRUE)
sizefact_mat[ind_na] <- NA
for (iter in seq_len(iterations)) {
featfact <- apply(object, 1, sum, na.rm = TRUE) / apply(sizefact_mat, 1, sum, na.rm = TRUE)
featfact_mat <- matrix(rep(featfact, n_sample), n_feature, n_sample)
featfact_mat[ind_na] <- NA
sizefact <- apply(object, 2, sum, na.rm = TRUE) / apply(featfact_mat, 2, sum, na.rm = TRUE)
if (size_scale == "first") {
scale_fac <- sizefact[1]
} else if (size_scale == "sum") {
scale_fac <- sum(sizefact)
}
sizefact <- sizefact / scale_fac
sizefact_mat <- matrix(rep(sizefact, n_feature), n_feature, n_sample, byrow = TRUE)
sizefact_mat[ind_na] <- NA
message(sprintf(
"Iteration = %s, squared error = %e",
iter,
sum((sizefact - sizefact0)^2) + sum((featfact - featfact0)^2)
))
if (sum((sizefact - sizefact0)^2) + sum((featfact - featfact0)^2) < tol) {
break
}
sizefact0 <- sizefact
featfact0 <- featfact
}
message("Model converged.")
return(list(
sizefact = sizefact,
featfact = featfact,
countmat = object
))
}
)
#' Estimate Poisson background model for multiple slides
#'
#' Estimate Poisson background model for multiple slides:
#'
#' @param object count matrix with features in rows and samples in columns
#' @param id character vector same size as sample size representing slide names of each sample
#' @param iterations maximum iterations to be run, default=10
#' @param tol tolerance to determine convergence, default = 1e-3
#' @param size_scale method to scale the sizefact, sum(sizefact)=1 when size_scale="sum", sizefact[1]=1 when size_scale="first"
#' @param ... additional argument list that might be used
#'
#' @return a list of following items
#' \itemize{
#' \item sizefact - estimated size factor
#' \item featfact - estimated feature factor matrix, column names the same as the slide id
#' \item countmat - the input count matrix
#' \item id - the input id
#' }
#'
#'
#' @docType methods
#' @rdname fitPoisBG_sp-methods
#'
setGeneric("fitPoisBG_sp",
signature = c("object"),
function(object, ...) standardGeneric("fitPoisBG_sp")
)
#' @rdname fitPoisBG_sp-methods
#' @aliases fitPoisBG_sp,matrix-method
setMethod(
"fitPoisBG_sp", "matrix",
function(object, id, iterations = 10, tol = 1e-3, size_scale = c("sum", "first")) {
size_scale <- match.arg(size_scale)
uniid <- unique(as.character(id))
n_feature <- NROW(object)
n_sample <- NCOL(object)
ind_na <- which(is.na(object), arr.ind = TRUE)
sizefact <- apply(object, 2, mean, na.rm = TRUE)
if (size_scale == "first") {
scale_fac <- sizefact[1]
} else if (size_scale == "sum") {
scale_fac <- sum(sizefact)
}
sizefact <- sizefact / scale_fac
sizefact0 <- sizefact
sizefact_mat <- matrix(rep(sizefact, n_feature), n_feature, n_sample, byrow = TRUE)
sizefact_mat[ind_na] <- NA
featfact0 <- matrix(0, n_feature, length(uniid))
for (iter in seq_len(iterations)) {
featfact <- sapply(uniid, function(x) {
apply(object[, x == id, drop = FALSE], 1, sum, na.rm = TRUE) /
apply(sizefact_mat[, x == id, drop = FALSE], 1, sum, na.rm = TRUE)
})
featfact_mat <- featfact[, id]
featfact_mat[ind_na] <- NA
sizefact <- apply(object, 2, sum, na.rm = TRUE) / apply(featfact_mat, 2, sum, na.rm = TRUE)
if (size_scale == "first") {
scale_fac <- sizefact[1]
} else if (size_scale == "sum") {
scale_fac <- sum(sizefact)
}
sizefact <- sizefact / scale_fac
sizefact_mat <- matrix(rep(sizefact, n_feature), n_feature, n_sample, byrow = TRUE)
sizefact_mat[ind_na] <- NA
message(sprintf(
"Iteration = %s, squared error = %e",
iter,
sum((sizefact - sizefact0)^2) + sum((featfact - featfact0)^2)
))
if (sum((sizefact - sizefact0)^2) + sum((featfact - featfact0)^2) < tol) {
break
}
sizefact0 <- sizefact
featfact0 <- featfact
}
message("Model converged.")
return(list(
sizefact = sizefact,
featfact = featfact,
countmat = object,
id = id
))
}
)
#' Perform diagnosis on Poisson background model
#'
#' Perform diagnosis on Poisson background model
#'
#'
#' @param object a valid GeoMx S4 object
#' @param split indicator variable on whether it is for multiple slides (Yes, TRUE; No, FALSE)
#' @param padj whether to adjust p value for outlier detection, default =TRUE
#' @param padj_method p value adjustment method, default ="BH"
#' @param cutoff p value(or adjusted p value) cutoff to determine outliers
#' @param generate_ppplot whether to generate ppplot, default =TRUE
#' @param ... additional argument list that might be used
#'
#' @importFrom Biobase pData
#' @importFrom Biobase fData
#' @importFrom Biobase exprs
#' @importFrom Biobase notes
#' @importFrom Biobase assayDataElement
#'
#'
#' @return a valid S4 object
#' \itemize{
#' \item lowtail - A matrix of lower tail probabilty, in assay slot
#' \item uptail - A matrix of upper tail probability, in assay slot
#' \item disper (or disper_sp if non single-valued groupvar is provided) - dispersion parameter in experimenetData
#' \item low_outlier - A matrix to indicate lower outliers (0:False, 1:True) in assay slot
#' \item upper_outlier - A matrix to indicate upper outliers (0:False, 1:True) in assay slot
#' }
#'
#' @examples
#' data(demoData)
#' demoData <- fitPoisBG(demoData, size_scale = "sum")
#' demoData <- diagPoisBG(demoData)
#' Biobase::notes(demoData)$disper
#' demoData <- fitPoisBG(demoData, groupvar = "slide name")
#' demoData <- diagPoisBG(demoData, split = TRUE)
#' Biobase::notes(demoData)$disper_sp
#' @export
#' @docType methods
#' @rdname diagPoisBG-methods
setGeneric("diagPoisBG",
signature = c("object"),
function(object, ...) standardGeneric("diagPoisBG")
)
#' @rdname diagPoisBG-methods
#' @aliases diagPoisBG,NanoStringGeoMxSet-method
setMethod(
"diagPoisBG", "NanoStringGeoMxSet",
function(object, split = FALSE, padj = FALSE, padj_method = "BH", cutoff = 1e-6, generate_ppplot = TRUE) {
negdat <- object[which(Biobase::fData(object)$CodeClass == "Negative"), ]
countmat <- Biobase::exprs(negdat)
pDat <- Biobase::pData(negdat)
fDat <- Biobase::fData(negdat)
if (isFALSE(split)) {
if (!any(c("sizefact" %in% colnames(pDat), "featfact" %in% colnames(fDat)))) {
stop("Please run `fitPoisBG` first. If you run `fitPoisBG` before, please specify `split = TRUE`.")
}
sizefact <- setNames(pDat[["sizefact"]], rownames(pDat))
featfact <- setNames(fDat[["featfact"]], rownames(fDat))
BGmod <- list(
sizefact = sizefact,
featfact = featfact,
countmat = countmat
)
} else {
if (!any(c("sizefact_sp" %in% colnames(pDat), "featfact_" %in% colnames(fDat)))) {
stop("Please run `fitPoisBG` first with `groupvar`.")
}
sizefact <- setNames(pDat[["sizefact_sp"]], rownames(pDat))
featfact <- fDat[, grep("featfact_", colnames(fDat))]
colnames(featfact) <- gsub("featfact_", "", colnames(featfact))
idvar <- Biobase::notes(object)[["fitPoisBG_sp_var"]]
id <- pDat[[idvar]]
message(sprintf("The results are based on stored `groupvar`, %s", idvar))
BGmod <- list(
sizefact = sizefact,
featfact = as.matrix(featfact),
countmat = countmat,
id = id
)
}
result <- diagPoisBG(BGmod,
padj = padj,
padj_method = padj_method,
cutoff = cutoff,
generate_ppplot = generate_ppplot
)
# add lowtail matrix
lowtail_mat <- matrix(NA,
nrow = nrow(object), ncol = ncol(object),
dimnames = dimnames(object)
)
lowtail_mat[rownames(result$uptail_prob), colnames(result$uptail_prob)] <- result$uptail_prob
Biobase::assayDataElement(object, "lowtail_prob") <- lowtail_mat
# add uptail matrix
uptail_mat <- matrix(NA,
nrow = nrow(object), ncol = ncol(object),
dimnames = dimnames(object)
)
uptail_mat[rownames(result$uptail_prob), colnames(result$uptail_prob)] <- result$uptail_prob
Biobase::assayDataElement(object, "uptail_prob") <- uptail_mat
# add disper parameter
if (isTRUE(split)) {
Biobase::notes(object)$disper_sp <- result$disper
} else {
Biobase::notes(object)$disper <- result$disper
}
# add upper tail outlier
low_outlier_mat <- matrix(0,
nrow = nrow(object), ncol = ncol(object),
dimnames = dimnames(object)
)
for (i in seq_len(nrow(result$outlier$low_outlier))) {
low_outlier_mat[rownames(result$outlier$low_outlier)[i], result$outlier$low_outlier[i, "col"]] <- 1
}
Biobase::assayDataElement(object, "low_outlier") <- low_outlier_mat
# add lower tail outlier
up_outlier_mat <- matrix(0,
nrow = nrow(object), ncol = ncol(object),
dimnames = dimnames(object)
)
for (i in seq_len(nrow(result$outlier$up_outlier))) {
up_outlier_mat[rownames(result$outlier$up_outlier)[i], result$outlier$up_outlier[i, "col"]] <- 1
}
Biobase::assayDataElement(object, "up_outlier") <- up_outlier_mat
return(object)
}
)
#' Perform diagnosis on Poisson background model
#'
#' Perform diagnosis on Poisson background model
#'
#' @param object a list of sizefact, featfact, countmat, or id (if it is for mutliple slides)
#' @param padj whether to adjust p value for outlier detection, default =TRUE
#' @param padj_method p value adjustment method, default ="BH"
#' @param cutoff p value(or adjusted p value) cutoff to determine outliers
#' @param generate_ppplot whether to generate ppplot, default =TRUE
#'
#'
#' @importFrom graphics abline
#'
#' @return a list of following items
#' \itemize{
#' \item lowtail - A matrix of lower tail probabilty
#' \item uptail - A matrix of upper tail probability
#' \item disper - dispersion parameter
#' \item outlier - A list of coodinates of lower and upper outliers
#' }
#' @rdname diagPoisBG-methods
#' @aliases diagPoisBG,list-method
setMethod(
"diagPoisBG", "list",
function(object, padj = FALSE, padj_method = "BH", cutoff = 1e-6, generate_ppplot = TRUE) {
countmat <- object$countmat
if (NCOL(object$featfact) == 1) {
countmat_expected <- (object$featfact %*% t(object$sizefact))
} else {
countmat_expected <- sweep(object$featfact[, object$id], 2, object$sizefact, FUN = "*")
}
countmat <- as.matrix(countmat)
lowtail_prob1 <- ppois(q = countmat, lambda = countmat_expected)
lowtail_prob2 <- ppois(q = countmat - 1, lambda = countmat_expected)
lowtail_prob <- (lowtail_prob1 + lowtail_prob2) / 2
uptail_prob <- 1 - lowtail_prob
# simualte data (do it only once)
countmat_simu <- t(apply(countmat_expected, 1, function(x) rpois(rep(1, ncol(countmat)), lambda = x)))
lowtail_prob1_simu <- ppois(q = countmat_simu, lambda = countmat_expected)
lowtail_prob2_simu <- ppois(q = countmat_simu - 1, lambda = countmat_expected)
lowtail_prob_simu <- (lowtail_prob1_simu + lowtail_prob2_simu) / 2
if (generate_ppplot) {
y <- sort(lowtail_prob, na.last = TRUE)
y_simu <- sort(lowtail_prob_simu, na.last = TRUE)
plot(y_simu, y, ylim = c(0, 1), xlab = "Empircal CDF from simulated data", ylab = "Empircal CDF", main = "Poisson model")
graphics::abline(a = 0, b = 1)
}
disper <- mean((countmat - countmat_expected)^2 / countmat_expected, na.rm = TRUE)
if (padj) {
lowtail_prob <- matrix(p.adjust(lowtail_prob, method = padj_method), nrow = nrow(lowtail_prob), ncol = ncol(lowtail_prob))
uptail_prob <- matrix(p.adjust(uptail_prob, method = padj_method), nrow = nrow(uptail_prob), ncol = ncol(uptail_prob))
}
low_outlier <- which(lowtail_prob < cutoff, arr.ind = TRUE)
up_outlier <- which(uptail_prob < cutoff, arr.ind = TRUE)
return(list(
lowtail_prob = lowtail_prob,
uptail_prob = uptail_prob,
disper = disper,
outlier = list(
low_outlier = low_outlier,
up_outlier = up_outlier
)
))
}
)
#' Compute Quantile Range
#'
#' Compute Quantile Range, a metric representing signal strength for QC purpose
#'
#' @param object a valid GeoMx S4 object
#' @param split indicator variable on whether it is for multiple slides
#' @param probs numeric vector of probabilities with values in [0,1] passed to quantile
#' @param removeoutlier indicator on whether to remove outliers, default: FALSE
#' @param ... additional argument list that might be used
#'
#' @importFrom Biobase pData
#' @importFrom Biobase fData
#' @importFrom Biobase exprs
#' @importFrom Biobase notes
#' @importFrom Biobase annotation
#'
#'
#' @return a valid S4 object with probabilities in phenoData
#'
#' @examples
#' data(demoData)
#' demoData <- fitPoisBG(demoData, size_scale = "sum")
#' demoData <- diagPoisBG(demoData)
#' demoData <- aggreprobe(demoData, use = "cor")
#' Biobase::notes(demoData)$disper
#' demoData <- QuanRange(demoData, split = FALSE, probs = c(0.75, 0.8, 0.9, 0.95))
#'
#' data(demoData)
#' demoData <- fitPoisBG(demoData, groupvar = "slide name")
#' demoData <- diagPoisBG(demoData, split = TRUE)
#' demoData <- aggreprobe(demoData, use = "cor")
#' Biobase::notes(demoData)$disper_sp
#' demoData <- QuanRange(demoData, split = TRUE, probs = c(0.75, 0.8, 0.9, 0.95))
#' @export
#' @docType methods
#' @rdname QuanRange-methods
setGeneric("QuanRange",
signature = c("object"),
function(object, ...) standardGeneric("QuanRange")
)
#' @rdname QuanRange-methods
#' @aliases QuanRange,NanoStringGeoMxSet-method
setMethod(
"QuanRange", "NanoStringGeoMxSet",
function(object, split = FALSE, probs, removeoutlier = FALSE, ...) {
fDat <- Biobase::fData(object)
pDat <- Biobase::pData(object)
# get the positive probes
posdat <- object[-which(fDat$CodeClass == "Negative"), ]
countmat <- Biobase::exprs(posdat)
# get the negative probes
negdat <- object[which(fDat$CodeClass == "Negative"), ]
pDatNeg <- Biobase::pData(negdat)
fDatNeg <- Biobase::fData(negdat)
if (isFALSE(split)) {
if (!any(c("sizefact" %in% colnames(pDat), "featfact" %in% colnames(fDat)))) {
stop("Please run `fitPoisBG` first. If you run `fitPoisBG` before, please specify `split = TRUE`.")
}
sizefact <- setNames(pDatNeg[["sizefact"]], rownames(pDatNeg))
featfact <- setNames(fDatNeg[["featfact"]], rownames(fDatNeg))
BGmod <- list(
sizefact = sizefact,
featfact = featfact,
countmat = countmat
)
} else {
if (!any(c("sizefact_sp" %in% colnames(pDatNeg), "featfact_" %in% colnames(fDatNeg)))) {
stop("Please run `fitPoisBG` first with `groupvar`.")
}
sizefact <- setNames(pDatNeg[["sizefact_sp"]], rownames(pDatNeg))
featfact <- fDatNeg[, grep("featfact_", colnames(fDatNeg))]
colnames(featfact) <- gsub("featfact_", "", colnames(featfact))
idvar <- Biobase::notes(object)[["fitPoisBG_sp_var"]]
id <- pDat[[idvar]]
message(sprintf("The results are based on stored `groupvar`, %s", idvar))
BGmod <- list(
sizefact = sizefact,
featfact = as.matrix(featfact),
countmat = countmat,
id = id
)
}
# calculate probenum for the dataset
if ("probenum" %in% fvarLabels(posdat)) {
probenum <- fData(posdat)[["probenum"]]
} else {
stop("No `probenum` is found. Run `aggreprobe` first.")
}
names(probenum) <- rownames(fData(posdat))
result <- QuanRange(
object = countmat,
probenum = probenum,
BGmod = BGmod,
probs = probs,
removeoutlier = removeoutlier
)
for (prob in as.character(probs)) {
object[[prob]] <- result[, prob]
}
return(object)
}
)
#' Compute Quantile Range
#'
#' Compute Quantile Range, a metric representing signal strength for QC purpose
#'
#' @param object count matrix with features in rows and samples in columns
#' @param BGmod a list of sizefact, sizefact, countmat, and id (if it is for multiple slides)
#' @param probenum a vector of numbers of probes in each gene
#' @param probs numeric vector of probabilities with values in [0,1] passed to quantile
#' @param removeoutlier indicator on whether to remove outliers, default: FALSE
#'
#'
#' @importFrom graphics boxplot
#'
#' @return a matrix of quantile range in rows and probs in columns
#'
#' @rdname QuanRange-methods
#' @aliases QuanRange,matrix-method
setMethod(
"QuanRange", "matrix",
function(object, probenum, BGmod, probs, removeoutlier = FALSE) {
if (NCOL(BGmod$featfact) == 1) {
if (removeoutlier == TRUE) {
boxobj <- graphics::boxplot(BGmod$featfact, plot = FALSE)
if (length(boxobj$out) > 0) {
featfact <- BGmod$featfact[-which(BGmod$featfact %in% boxobj$out)]
} else {
featfact <- BGmod$featfact
}
message(sprintf("%s negative probes are removed prior to the score test.", length(boxobj$out)))
} else {
featfact <- BGmod$featfact
}
back <- mean(featfact) * BGmod$sizefact
} else {
if (removeoutlier == TRUE) {
featfact <- apply(BGmod$featfact, 2, function(x) {
boxobj <- graphics::boxplot(x, plot = FALSE)
message(sprintf("%s negative probes are removed prior to the score test.", length(boxobj$out)))
x[which(x %in% boxobj$out)] <- NA
x
})
} else {
featfact <- BGmod$featfact
}
back <- colMeans(featfact[, BGmod$id], na.rm = TRUE) * BGmod$sizefact
}
object <- sweep(object, 1, probenum, FUN = "/")
quan <- sapply(probs, function(y) apply(object, 2, function(x) quantile(x, probs = y)))
colnames(quan) <- probs
quanrange <- sweep(quan, 1, back, FUN = "-")
return(quanrange)
}
)
Nanostring-Biostats/GeoDiff documentation built on Dec. 19, 2024, 7:22 p.m.
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#' Estimate Poisson background model for either single slide or multiple slides
#'
#' Estimate Poisson background model for either single slide or multiple slides
#'
#' @param object a valid GeoMx S4 object
#' @param groupvar the group variable name for slide
#' @param iterations maximum iterations to be run, default=10
#' @param tol tolerance to determine convergence, default = 1e-3
#' @param size_scale method to scale the sizefact, sum(sizefact)=1 when size_scale="sum", sizefact[1]=1 when size_scale="first"
#' @param ... additional argument list that might be used
#'
#' @importFrom Biobase exprs
#' @importFrom Biobase fData
#' @importFrom Biobase sampleNames
#' @importFrom Biobase featureNames
#'
#' @return a valid GeoMx S4 object if split is FALSE
#' \itemize{
#' \item sizefact - estimated size factor in phenoData
#' \item featfact - estimated feature factor in featureData
#' }
#'
#' a valid GeoMx S4 object if split is TRUE,
#' \itemize{
#' \item sizefact - estimated size factor in phenoData
#' \item featfact_XX - estimated feature factor vector, column name (denoted as XX) the same as the slide id, in featureData for each unique slide
#' \item fitPoisBG_sp_var - the column name for slide, in experimentData
#' }
#'
#' @examples
#'
#' data(demoData)
#' demoData <- fitPoisBG(demoData, size_scale = "sum")
#' data(demoData)
#' demoData <- fitPoisBG(demoData, groupvar = "slide name", size_scale = "sum")
#' @export
#' @docType methods
#' @rdname fitPoisBG-methods
setGeneric("fitPoisBG",
signature = c("object"),
function(object, ...) standardGeneric("fitPoisBG")
)
#' @rdname fitPoisBG-methods
#' @aliases fitPoisBG,NanoStringGeoMxSet-method
setMethod(
"fitPoisBG", "NanoStringGeoMxSet",
function(object, groupvar = NULL, iterations = 10, tol = 1e-3, size_scale = c("sum", "first"), ...) {
# check on tol
tol <- as.double(tol)
stopifnot(length(tol) == 1)
stopifnot(tol >= 0)
# extract the negative probes matrix
negdat <- object[which(Biobase::fData(object)$CodeClass == "Negative"), ]
countmat <- Biobase::exprs(negdat)
if (is.null(groupvar)) {
# fit the model as a single slide
split <- FALSE
} else if (!(groupvar %in% varLabels(object))) {
stop(sprintf("%s is not found in the S4 object.", groupvar))
} else {
# extract the groupvar
id <- object[[groupvar]]
if (length(unique(id)) == 1) {
# this is equivalent as fitting the model as a single slide
split <- FALSE
warning(sprintf("`%s` has only one value, %s", groupvar, unique(id)))
} else {
# fit the model for multiple slides
split <- TRUE
}
}
if (isFALSE(split)) {
# calling the fitPoisBG function when split is FALSE
result <- fitPoisBG(
object = countmat,
iterations = iterations,
tol = tol,
size_scale = size_scale
)
object[["sizefact"]] <- result$sizefact[Biobase::sampleNames(object)]
Biobase::fData(object)[["featfact"]] <- NA
Biobase::fData(object)[["featfact"]][match(names(result$featfact), Biobase::featureNames(object), nomatch = 0)] <- result$featfact
} else {
# calling the fitPoisBG_sp function when split is TRUE
result <- fitPoisBG_sp(
object = countmat,
id = id,
iterations = iterations,
tol = tol,
size_scale = size_scale
)
# append results to the object
object[["sizefact_sp"]] <- result$sizefact[Biobase::sampleNames(object)]
for (index in unique(result$id)) {
Biobase::fData(object)[[paste0("featfact_", index)]] <- NA
Biobase::fData(object)[[paste0("featfact_", index)]][match(rownames(result$featfact), Biobase::featureNames(object), nomatch = 0)] <- result$featfact[, index]
}
Biobase::notes(object)$fitPoisBG_sp_var <- groupvar
}
return(object)
}
)
#' Estimate Poisson background model
#'
#' Estimate Poisson background model:
#'
#' @param object count matrix with features in rows and samples in columns
#' @param iterations maximum iterations to be run, default=10
#' @param tol tolerance to determine convergence, default = 1e-3
#' @param size_scale method to scale the sizefact, sum(sizefact)=1 when size_scale="sum", sizefact[1]=1 when size_scale="first"
#'
#' @return a list of following items
#' \itemize{
#' \item sizefact - estimated size factor
#' \item featfact - estimated feature factor
#' \item countmat - the input count matrix
#' }
#'
#' @rdname fitPoisBG-methods
#' @aliases fitPoisBG,matrix-method
setMethod(
"fitPoisBG", "matrix",
function(object, iterations = 10, tol = 1e-3, size_scale = c("sum", "first")) {
size_scale <- match.arg(size_scale)
n_feature <- NROW(object)
n_sample <- NCOL(object)
ind_na <- which(is.na(object), arr.ind = TRUE)
featfact0 <- numeric(n_feature)
sizefact <- apply(object, 2, mean, na.rm = TRUE)
if (size_scale == "first") {
scale_fac <- sizefact[1]
} else if (size_scale == "sum") {
scale_fac <- sum(sizefact)
}
sizefact <- sizefact / scale_fac
sizefact0 <- sizefact
sizefact_mat <- matrix(rep(sizefact, n_feature), n_feature, n_sample, byrow = TRUE)
sizefact_mat[ind_na] <- NA
for (iter in seq_len(iterations)) {
featfact <- apply(object, 1, sum, na.rm = TRUE) / apply(sizefact_mat, 1, sum, na.rm = TRUE)
featfact_mat <- matrix(rep(featfact, n_sample), n_feature, n_sample)
featfact_mat[ind_na] <- NA
sizefact <- apply(object, 2, sum, na.rm = TRUE) / apply(featfact_mat, 2, sum, na.rm = TRUE)
if (size_scale == "first") {
scale_fac <- sizefact[1]
} else if (size_scale == "sum") {
scale_fac <- sum(sizefact)
}
sizefact <- sizefact / scale_fac
sizefact_mat <- matrix(rep(sizefact, n_feature), n_feature, n_sample, byrow = TRUE)
sizefact_mat[ind_na] <- NA
message(sprintf(
"Iteration = %s, squared error = %e",
iter,
sum((sizefact - sizefact0)^2) + sum((featfact - featfact0)^2)
))
if (sum((sizefact - sizefact0)^2) + sum((featfact - featfact0)^2) < tol) {
break
}
sizefact0 <- sizefact
featfact0 <- featfact
}
message("Model converged.")
return(list(
sizefact = sizefact,
featfact = featfact,
countmat = object
))
}
)
#' Estimate Poisson background model for multiple slides
#'
#' Estimate Poisson background model for multiple slides:
#'
#' @param object count matrix with features in rows and samples in columns
#' @param id character vector same size as sample size representing slide names of each sample
#' @param iterations maximum iterations to be run, default=10
#' @param tol tolerance to determine convergence, default = 1e-3
#' @param size_scale method to scale the sizefact, sum(sizefact)=1 when size_scale="sum", sizefact[1]=1 when size_scale="first"
#' @param ... additional argument list that might be used
#'
#' @return a list of following items
#' \itemize{
#' \item sizefact - estimated size factor
#' \item featfact - estimated feature factor matrix, column names the same as the slide id
#' \item countmat - the input count matrix
#' \item id - the input id
#' }
#'
#'
#' @docType methods
#' @rdname fitPoisBG_sp-methods
#'
setGeneric("fitPoisBG_sp",
signature = c("object"),
function(object, ...) standardGeneric("fitPoisBG_sp")
)
#' @rdname fitPoisBG_sp-methods
#' @aliases fitPoisBG_sp,matrix-method
setMethod(
"fitPoisBG_sp", "matrix",
function(object, id, iterations = 10, tol = 1e-3, size_scale = c("sum", "first")) {
size_scale <- match.arg(size_scale)
uniid <- unique(as.character(id))
n_feature <- NROW(object)
n_sample <- NCOL(object)
ind_na <- which(is.na(object), arr.ind = TRUE)
sizefact <- apply(object, 2, mean, na.rm = TRUE)
if (size_scale == "first") {
scale_fac <- sizefact[1]
} else if (size_scale == "sum") {
scale_fac <- sum(sizefact)
}
sizefact <- sizefact / scale_fac
sizefact0 <- sizefact
sizefact_mat <- matrix(rep(sizefact, n_feature), n_feature, n_sample, byrow = TRUE)
sizefact_mat[ind_na] <- NA
featfact0 <- matrix(0, n_feature, length(uniid))
for (iter in seq_len(iterations)) {
featfact <- sapply(uniid, function(x) {
apply(object[, x == id, drop = FALSE], 1, sum, na.rm = TRUE) /
apply(sizefact_mat[, x == id, drop = FALSE], 1, sum, na.rm = TRUE)
})
featfact_mat <- featfact[, id]
featfact_mat[ind_na] <- NA
sizefact <- apply(object, 2, sum, na.rm = TRUE) / apply(featfact_mat, 2, sum, na.rm = TRUE)
if (size_scale == "first") {
scale_fac <- sizefact[1]
} else if (size_scale == "sum") {
scale_fac <- sum(sizefact)
}
sizefact <- sizefact / scale_fac
sizefact_mat <- matrix(rep(sizefact, n_feature), n_feature, n_sample, byrow = TRUE)
sizefact_mat[ind_na] <- NA
message(sprintf(
"Iteration = %s, squared error = %e",
iter,
sum((sizefact - sizefact0)^2) + sum((featfact - featfact0)^2)
))
if (sum((sizefact - sizefact0)^2) + sum((featfact - featfact0)^2) < tol) {
break
}
sizefact0 <- sizefact
featfact0 <- featfact
}
message("Model converged.")
return(list(
sizefact = sizefact,
featfact = featfact,
countmat = object,
id = id
))
}
)
#' Perform diagnosis on Poisson background model
#'
#' Perform diagnosis on Poisson background model
#'
#'
#' @param object a valid GeoMx S4 object
#' @param split indicator variable on whether it is for multiple slides (Yes, TRUE; No, FALSE)
#' @param padj whether to adjust p value for outlier detection, default =TRUE
#' @param padj_method p value adjustment method, default ="BH"
#' @param cutoff p value(or adjusted p value) cutoff to determine outliers
#' @param generate_ppplot whether to generate ppplot, default =TRUE
#' @param ... additional argument list that might be used
#'
#' @importFrom Biobase pData
#' @importFrom Biobase fData
#' @importFrom Biobase exprs
#' @importFrom Biobase notes
#' @importFrom Biobase assayDataElement
#'
#'
#' @return a valid S4 object
#' \itemize{
#' \item lowtail - A matrix of lower tail probabilty, in assay slot
#' \item uptail - A matrix of upper tail probability, in assay slot
#' \item disper (or disper_sp if non single-valued groupvar is provided) - dispersion parameter in experimenetData
#' \item low_outlier - A matrix to indicate lower outliers (0:False, 1:True) in assay slot
#' \item upper_outlier - A matrix to indicate upper outliers (0:False, 1:True) in assay slot
#' }
#'
#' @examples
#' data(demoData)
#' demoData <- fitPoisBG(demoData, size_scale = "sum")
#' demoData <- diagPoisBG(demoData)
#' Biobase::notes(demoData)$disper
#' demoData <- fitPoisBG(demoData, groupvar = "slide name")
#' demoData <- diagPoisBG(demoData, split = TRUE)
#' Biobase::notes(demoData)$disper_sp
#' @export
#' @docType methods
#' @rdname diagPoisBG-methods
setGeneric("diagPoisBG",
signature = c("object"),
function(object, ...) standardGeneric("diagPoisBG")
)
#' @rdname diagPoisBG-methods
#' @aliases diagPoisBG,NanoStringGeoMxSet-method
setMethod(
"diagPoisBG", "NanoStringGeoMxSet",
function(object, split = FALSE, padj = FALSE, padj_method = "BH", cutoff = 1e-6, generate_ppplot = TRUE) {
negdat <- object[which(Biobase::fData(object)$CodeClass == "Negative"), ]
countmat <- Biobase::exprs(negdat)
pDat <- Biobase::pData(negdat)
fDat <- Biobase::fData(negdat)
if (isFALSE(split)) {
if (!any(c("sizefact" %in% colnames(pDat), "featfact" %in% colnames(fDat)))) {
stop("Please run `fitPoisBG` first. If you run `fitPoisBG` before, please specify `split = TRUE`.")
}
sizefact <- setNames(pDat[["sizefact"]], rownames(pDat))
featfact <- setNames(fDat[["featfact"]], rownames(fDat))
BGmod <- list(
sizefact = sizefact,
featfact = featfact,
countmat = countmat
)
} else {
if (!any(c("sizefact_sp" %in% colnames(pDat), "featfact_" %in% colnames(fDat)))) {
stop("Please run `fitPoisBG` first with `groupvar`.")
}
sizefact <- setNames(pDat[["sizefact_sp"]], rownames(pDat))
featfact <- fDat[, grep("featfact_", colnames(fDat))]
colnames(featfact) <- gsub("featfact_", "", colnames(featfact))
idvar <- Biobase::notes(object)[["fitPoisBG_sp_var"]]
id <- pDat[[idvar]]
message(sprintf("The results are based on stored `groupvar`, %s", idvar))
BGmod <- list(
sizefact = sizefact,
featfact = as.matrix(featfact),
countmat = countmat,
id = id
)
}
result <- diagPoisBG(BGmod,
padj = padj,
padj_method = padj_method,
cutoff = cutoff,
generate_ppplot = generate_ppplot
)
# add lowtail matrix
lowtail_mat <- matrix(NA,
nrow = nrow(object), ncol = ncol(object),
dimnames = dimnames(object)
)
lowtail_mat[rownames(result$uptail_prob), colnames(result$uptail_prob)] <- result$uptail_prob
Biobase::assayDataElement(object, "lowtail_prob") <- lowtail_mat
# add uptail matrix
uptail_mat <- matrix(NA,
nrow = nrow(object), ncol = ncol(object),
dimnames = dimnames(object)
)
uptail_mat[rownames(result$uptail_prob), colnames(result$uptail_prob)] <- result$uptail_prob
Biobase::assayDataElement(object, "uptail_prob") <- uptail_mat
# add disper parameter
if (isTRUE(split)) {
Biobase::notes(object)$disper_sp <- result$disper
} else {
Biobase::notes(object)$disper <- result$disper
}
# add upper tail outlier
low_outlier_mat <- matrix(0,
nrow = nrow(object), ncol = ncol(object),
dimnames = dimnames(object)
)
for (i in seq_len(nrow(result$outlier$low_outlier))) {
low_outlier_mat[rownames(result$outlier$low_outlier)[i], result$outlier$low_outlier[i, "col"]] <- 1
}
Biobase::assayDataElement(object, "low_outlier") <- low_outlier_mat
# add lower tail outlier
up_outlier_mat <- matrix(0,
nrow = nrow(object), ncol = ncol(object),
dimnames = dimnames(object)
)
for (i in seq_len(nrow(result$outlier$up_outlier))) {
up_outlier_mat[rownames(result$outlier$up_outlier)[i], result$outlier$up_outlier[i, "col"]] <- 1
}
Biobase::assayDataElement(object, "up_outlier") <- up_outlier_mat
return(object)
}
)
#' Perform diagnosis on Poisson background model
#'
#' Perform diagnosis on Poisson background model
#'
#' @param object a list of sizefact, featfact, countmat, or id (if it is for mutliple slides)
#' @param padj whether to adjust p value for outlier detection, default =TRUE
#' @param padj_method p value adjustment method, default ="BH"
#' @param cutoff p value(or adjusted p value) cutoff to determine outliers
#' @param generate_ppplot whether to generate ppplot, default =TRUE
#'
#'
#' @importFrom graphics abline
#'
#' @return a list of following items
#' \itemize{
#' \item lowtail - A matrix of lower tail probabilty
#' \item uptail - A matrix of upper tail probability
#' \item disper - dispersion parameter
#' \item outlier - A list of coodinates of lower and upper outliers
#' }
#' @rdname diagPoisBG-methods
#' @aliases diagPoisBG,list-method
setMethod(
"diagPoisBG", "list",
function(object, padj = FALSE, padj_method = "BH", cutoff = 1e-6, generate_ppplot = TRUE) {
countmat <- object$countmat
if (NCOL(object$featfact) == 1) {
countmat_expected <- (object$featfact %*% t(object$sizefact))
} else {
countmat_expected <- sweep(object$featfact[, object$id], 2, object$sizefact, FUN = "*")
}
countmat <- as.matrix(countmat)
lowtail_prob1 <- ppois(q = countmat, lambda = countmat_expected)
lowtail_prob2 <- ppois(q = countmat - 1, lambda = countmat_expected)
lowtail_prob <- (lowtail_prob1 + lowtail_prob2) / 2
uptail_prob <- 1 - lowtail_prob
# simualte data (do it only once)
countmat_simu <- t(apply(countmat_expected, 1, function(x) rpois(rep(1, ncol(countmat)), lambda = x)))
lowtail_prob1_simu <- ppois(q = countmat_simu, lambda = countmat_expected)
lowtail_prob2_simu <- ppois(q = countmat_simu - 1, lambda = countmat_expected)
lowtail_prob_simu <- (lowtail_prob1_simu + lowtail_prob2_simu) / 2
if (generate_ppplot) {
y <- sort(lowtail_prob, na.last = TRUE)
y_simu <- sort(lowtail_prob_simu, na.last = TRUE)
plot(y_simu, y, ylim = c(0, 1), xlab = "Empircal CDF from simulated data", ylab = "Empircal CDF", main = "Poisson model")
graphics::abline(a = 0, b = 1)
}
disper <- mean((countmat - countmat_expected)^2 / countmat_expected, na.rm = TRUE)
if (padj) {
lowtail_prob <- matrix(p.adjust(lowtail_prob, method = padj_method), nrow = nrow(lowtail_prob), ncol = ncol(lowtail_prob))
uptail_prob <- matrix(p.adjust(uptail_prob, method = padj_method), nrow = nrow(uptail_prob), ncol = ncol(uptail_prob))
}
low_outlier <- which(lowtail_prob < cutoff, arr.ind = TRUE)
up_outlier <- which(uptail_prob < cutoff, arr.ind = TRUE)
return(list(
lowtail_prob = lowtail_prob,
uptail_prob = uptail_prob,
disper = disper,
outlier = list(
low_outlier = low_outlier,
up_outlier = up_outlier
)
))
}
)
#' Compute Quantile Range
#'
#' Compute Quantile Range, a metric representing signal strength for QC purpose
#'
#' @param object a valid GeoMx S4 object
#' @param split indicator variable on whether it is for multiple slides
#' @param probs numeric vector of probabilities with values in [0,1] passed to quantile
#' @param removeoutlier indicator on whether to remove outliers, default: FALSE
#' @param ... additional argument list that might be used
#'
#' @importFrom Biobase pData
#' @importFrom Biobase fData
#' @importFrom Biobase exprs
#' @importFrom Biobase notes
#' @importFrom Biobase annotation
#'
#'
#' @return a valid S4 object with probabilities in phenoData
#'
#' @examples
#' data(demoData)
#' demoData <- fitPoisBG(demoData, size_scale = "sum")
#' demoData <- diagPoisBG(demoData)
#' demoData <- aggreprobe(demoData, use = "cor")
#' Biobase::notes(demoData)$disper
#' demoData <- QuanRange(demoData, split = FALSE, probs = c(0.75, 0.8, 0.9, 0.95))
#'
#' data(demoData)
#' demoData <- fitPoisBG(demoData, groupvar = "slide name")
#' demoData <- diagPoisBG(demoData, split = TRUE)
#' demoData <- aggreprobe(demoData, use = "cor")
#' Biobase::notes(demoData)$disper_sp
#' demoData <- QuanRange(demoData, split = TRUE, probs = c(0.75, 0.8, 0.9, 0.95))
#' @export
#' @docType methods
#' @rdname QuanRange-methods
setGeneric("QuanRange",
signature = c("object"),
function(object, ...) standardGeneric("QuanRange")
)
#' @rdname QuanRange-methods
#' @aliases QuanRange,NanoStringGeoMxSet-method
setMethod(
"QuanRange", "NanoStringGeoMxSet",
function(object, split = FALSE, probs, removeoutlier = FALSE, ...) {
fDat <- Biobase::fData(object)
pDat <- Biobase::pData(object)
# get the positive probes
posdat <- object[-which(fDat$CodeClass == "Negative"), ]
countmat <- Biobase::exprs(posdat)
# get the negative probes
negdat <- object[which(fDat$CodeClass == "Negative"), ]
pDatNeg <- Biobase::pData(negdat)
fDatNeg <- Biobase::fData(negdat)
if (isFALSE(split)) {
if (!any(c("sizefact" %in% colnames(pDat), "featfact" %in% colnames(fDat)))) {
stop("Please run `fitPoisBG` first. If you run `fitPoisBG` before, please specify `split = TRUE`.")
}
sizefact <- setNames(pDatNeg[["sizefact"]], rownames(pDatNeg))
featfact <- setNames(fDatNeg[["featfact"]], rownames(fDatNeg))
BGmod <- list(
sizefact = sizefact,
featfact = featfact,
countmat = countmat
)
} else {
if (!any(c("sizefact_sp" %in% colnames(pDatNeg), "featfact_" %in% colnames(fDatNeg)))) {
stop("Please run `fitPoisBG` first with `groupvar`.")
}
sizefact <- setNames(pDatNeg[["sizefact_sp"]], rownames(pDatNeg))
featfact <- fDatNeg[, grep("featfact_", colnames(fDatNeg))]
colnames(featfact) <- gsub("featfact_", "", colnames(featfact))
idvar <- Biobase::notes(object)[["fitPoisBG_sp_var"]]
id <- pDat[[idvar]]
message(sprintf("The results are based on stored `groupvar`, %s", idvar))
BGmod <- list(
sizefact = sizefact,
featfact = as.matrix(featfact),
countmat = countmat,
id = id
)
}
# calculate probenum for the dataset
if ("probenum" %in% fvarLabels(posdat)) {
probenum <- fData(posdat)[["probenum"]]
} else {
stop("No `probenum` is found. Run `aggreprobe` first.")
}
names(probenum) <- rownames(fData(posdat))
result <- QuanRange(
object = countmat,
probenum = probenum,
BGmod = BGmod,
probs = probs,
removeoutlier = removeoutlier
)
for (prob in as.character(probs)) {
object[[prob]] <- result[, prob]
}
return(object)
}
)
#' Compute Quantile Range
#'
#' Compute Quantile Range, a metric representing signal strength for QC purpose
#'
#' @param object count matrix with features in rows and samples in columns
#' @param BGmod a list of sizefact, sizefact, countmat, and id (if it is for multiple slides)
#' @param probenum a vector of numbers of probes in each gene
#' @param probs numeric vector of probabilities with values in [0,1] passed to quantile
#' @param removeoutlier indicator on whether to remove outliers, default: FALSE
#'
#'
#' @importFrom graphics boxplot
#'
#' @return a matrix of quantile range in rows and probs in columns
#'
#' @rdname QuanRange-methods
#' @aliases QuanRange,matrix-method
setMethod(
"QuanRange", "matrix",
function(object, probenum, BGmod, probs, removeoutlier = FALSE) {
if (NCOL(BGmod$featfact) == 1) {
if (removeoutlier == TRUE) {
boxobj <- graphics::boxplot(BGmod$featfact, plot = FALSE)
if (length(boxobj$out) > 0) {
featfact <- BGmod$featfact[-which(BGmod$featfact %in% boxobj$out)]
} else {
featfact <- BGmod$featfact
}
message(sprintf("%s negative probes are removed prior to the score test.", length(boxobj$out)))
} else {
featfact <- BGmod$featfact
}
back <- mean(featfact) * BGmod$sizefact
} else {
if (removeoutlier == TRUE) {
featfact <- apply(BGmod$featfact, 2, function(x) {
boxobj <- graphics::boxplot(x, plot = FALSE)
message(sprintf("%s negative probes are removed prior to the score test.", length(boxobj$out)))
x[which(x %in% boxobj$out)] <- NA
x
})
} else {
featfact <- BGmod$featfact
}
back <- colMeans(featfact[, BGmod$id], na.rm = TRUE) * BGmod$sizefact
}
object <- sweep(object, 1, probenum, FUN = "/")
quan <- sapply(probs, function(y) apply(object, 2, function(x) quantile(x, probs = y)))
colnames(quan) <- probs
quanrange <- sweep(quan, 1, back, FUN = "-")
return(quanrange)
}
)
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