aVirtualTwins/R/tree.R

344 lines
12 KiB
R

#' Tree to find subgroup
#'
#' An abstract reference class to compute tree
#'
#' \code{VT.tree.class} and \code{VT.tree.reg} are children of \code{VT.tree}.
#' \code{VT.tree.class} and \code{VT.tree.reg} try to find a strong association
#' between \code{difft} (in \code{VT.difft} object) and RCT variables.
#'
#' In \code{VT.tree.reg}, a regression tree is computed on \code{difft} values.
#' Then, thanks to the \code{threshold} it flags leafs of the \code{tree} which
#' are above the \code{threshold} (when \code{sens} is ">"). Or it flags leafs
#' which are below the \code{threshold} (when \code{sens} = "<").
#'
#' In \code{VT.tree.class}, it first flags \code{difft} above or below
#' (depending on the \code{sens}) the given \code{threshold}. Then a
#' classification tree is computed to find which variables explain flagged
#' \code{difft}.
#'
#' To sum up, \code{VT.tree} try to understand which variables are associated
#' with a big change of \code{difft}.
#'
#' Results are shown with \code{getRules()} function. \code{only.leaf} parameter
#' allows to obtain only the leaf of the \code{tree}. \code{only.fav} parameter
#' select only favorable nodes. \code{tables} shows incidence table of the rule.
#' \code{verbose} allow \code{getRules()} to be quiet. And \code{compete} show
#' also rules with \code{maxcompete} competitors from the \code{tree}.
#'
#' @include difft.R setClass.R
#'
#' @field vt.difft \code{VT.difft} object
#' @field outcome outcome vector from \code{rpart} function
#' @field threshold numeric Threshold for difft calculation (c)
#' @field screening Logical. TRUE if using varimp. Default is VT.object
#' screening field
#' @field sens character Sens can be ">" (default) or "<". Meaning :
#' \code{difft} > \code{threshold} or \code{difft} < \code{threshold}
#' @field name character Names of the tree
#' @field tree rpart Rpart object to construct the tree
#' @field Ahat vector Indicator of beglonging to Ahat
#'
#' @seealso \code{\link{VT.tree.reg}}, \code{\link{VT.tree.class}}
#'
#' @name VT.tree
#'
#' @import methods
#'
#' @rdname VT.tree-abstract
VT.tree <- setRefClass(
Class = "VT.tree",
fields = list(
vt.difft = "VT.difft",
outcome = "vector",
threshold = "numeric",
screening = "logical",
sens = "character",
name = "character",
tree = "rpart",
competitors = "data.frame",
Ahat = "vector"
),
methods = list(
initialize = function(vt.difft = VT.difft(), threshold = 0.05, sens = ">", screening = NULL){
.self$vt.difft <- vt.difft
.self$threshold <- threshold
.self$sens <- sens
.self$screening <- ifelse(is.null(screening), vt.difft$vt.object$screening, screening)
},
getData = function(){
"Return data used for tree computation"
d <- .self$vt.difft$vt.object$data[, 3:ncol(.self$vt.difft$vt.object$data)]
if(.self$screening == T){
d.tmp <- d
d <- d.tmp[, colnames(d.tmp) %in% .self$vt.difft$vt.object$varimp]
}
d <- data.frame(.self$outcome, d)
names(d) <- c(.self$name, colnames(d)[-1])
return(d)
},
computeNameOfTree = function(type){
"return label of response variable of the tree"
return(type)
if(.self$threshold < 0 ){
threshold.chr <- paste0("m", -.self$threshold)
}else{
threshold.chr <- as.character(.self$threshold)
}
tmp = strsplit(threshold.chr, "[.]")[[1]]
return(paste(type, tmp[1], tmp[2], sep = ""))
},
run = function(...){
"Compute tree with rpart parameters"
if(length(.self$vt.difft$difft) == 0) stop("VT.difft::difft is an empty vector")
},
getInfos = function(){
"Return infos about tree"
cat("\n")
cat(sprintf("Threshold = %0.4f", .self$threshold))
cat("\n")
cat(sprintf("Delta = %0.4f", .self$vt.difft$vt.object$delta))
cat("\n")
cat(sprintf("Sens : %s", .self$sens))
cat("\n")
cat(sprintf("Size of Ahat : %i", (sum(.self$Ahat))))
return(invisible(NULL))
},
getRules = function(only.leaf = F, only.fav = F, tables = T, verbose = T, compete = F){
"Return subgroups discovered by the tree. See details."
# No tree ?
if (length(.self$tree) == 0){
warning("VT.tree : no tree"); return(invisible(NULL));
}
# No rules ?
if(nrow(.self$tree$frame) < 2){
warning("VT.tree : no nodes"); return(invisible(NULL));
}
# delete root node
full.frame <- .self$tree$frame[-1, ]
if (only.fav == T){
if(inherits(.self, "VT.tree.reg")){
if(.self$sens == ">"){
frm.only.fav <- full.frame[full.frame$yval >= (.self$threshold), ]
} else {
frm.only.fav <- full.frame[full.frame$yval <= (.self$threshold), ]
}
}else if(inherits(.self, "VT.tree.class")){
frm.only.fav <- full.frame[full.frame$yval == 2, ]
}
frm <- frm.only.fav
}
if (only.leaf == T){
if(inherits(.self, "VT.tree.reg")){
frm.only.leaf <- full.frame[full.frame$var == "<leaf>", ]
}else if(inherits(.self, "VT.tree.class")){
frm.only.leaf <- full.frame[full.frame$var == "<leaf>", ]
}
frm <- frm.only.leaf
}
if (only.fav == T & only.leaf == T){
frm <- frm.only.leaf[ intersect(rownames(frm.only.leaf), rownames(frm.only.fav)) , ]
}else if (only.fav == F & only.leaf == F){
frm <- full.frame
}
# in case tree is empty or doesn't exist
if (ncol(frm) == 0){
warning("VT.tree : no rules"); return(invisible(NULL));
}
pth <- rpart::path.rpart(.self$tree, nodes = row.names(frm), print.it = F)
# Delete 'root' node of rule
pth <- lapply(pth, FUN = function(d) return(d[-1]))
nodes <- c()
if(isTRUE(compete)){
comp.df <- .self$createCompetitors()
comp <- comp.df$path
for(i in names(pth)){
tmp <- length(comp[comp == i][-1])
if(tmp>0){
tmp <- 1:tmp
tmp <- paste(i, tmp, sep = ".")
nodes <- c(nodes, i, tmp)
}else
nodes <- c(nodes, i)
}
}else
nodes <- names(pth)
rules <- data.frame(replicate(6, character(0), simplify = T), replicate(2, numeric(0), simplify = T), stringsAsFactors = F)
colnames(rules) <- c("Subgroup", "Subgroup size", "Treatement event rate", "Control event rate",
"Treatment sample size", "Control sample size", "RR (resub)", "RR (snd)")
for(i in nodes){
is.comp <- FALSE
if (isTRUE(length(grep("^\\d+\\.\\d+$", i)) > 0)){
tmp.str <- strsplit(x = i, split = ".", fixed = T)[[1]]
tmp.path <- as.numeric(tmp.str[1])
tmp.path.str <- tmp.str[1]
tmp.comp <- as.numeric(tmp.str[2])
l <- length(pth[[tmp.path.str]])
pth.text.c <- c(pth[[tmp.path.str]][-l], comp.df[comp.df$path == tmp.path, ][(tmp.comp+1), "string"])
pth.text <- paste(pth.text.c, collapse = " & ")
is.comp <- TRUE
}else{
pth.text <- paste(pth[[i]], collapse = " & ")
}
incid <- .self$getIncidences(pth.text)
rules[i, 1] <- pth.text
rules[i, 2] <- incid$table.selected$table[3, 3] #size subgroupg
rules[i, 3] <- incid$table.selected$table[4, 2] #treatment event rate
rules[i, 4] <- incid$table.selected$table[4, 1] #control event rate
rules[i, 5] <- incid$table.selected$table[3, 2] #treatment sample size
rules[i, 6] <- incid$table.selected$table[3, 1] #control sample size
rules[i, 7] <- round(incid$table.selected$rr, digits = 3) # rr (resub)
rules[i, 8] <- round(incid$table.selected$rr.snd, digits = 3) # rr (snd)
if(isTRUE(verbose)){
cat("----------------------------\n")
cat(sprintf("| Rule number %s : ", i))
if(isTRUE(!is.comp)){
if(inherits(.self, "VT.tree.reg")){
cat(sprintf("Y val = %0.3f \n", frm[i, ]$yval))
}else{
cat(sprintf("Y val = %i \n", frm[i, ]$yval))
}
cat("----------------------------\n")
cat(sprintf("[n = %i", frm[i, ]$n))
cat(sprintf(", loss = %s, prob = %0.2f",
frm[i, ]$dev,
frm[i, ]$yval2[, 5]))
cat("] \n")
cat("\t\t")
cat(pth[[i]], sep="\n\t\t")
} else {
cat("\n----------------------------\n")
cat("\t\t")
cat(pth.text.c, sep="\n\t\t")
}
if(isTRUE(tables)){
cat("\n")
cat(sprintf("Incidence in selection \n"))
print(incid$table.selected$table)
cat("\n")
cat(sprintf("Relative risk (resub) : %0.3f \n", incid$table.selected$rr))
cat(sprintf("Relative risk (snd) : %0.3f \n\n", incid$table.selected$rr.snd))
cat(sprintf("Incidence in complement\n"))
print(incid$table.not.selected$table)
cat("\n")
cat(sprintf("Relative risk (resub) : %0.3f \n", incid$table.not.selected$rr))
cat(sprintf("Relative risk (snd) : %0.3f \n\n", incid$table.not.selected$rr.snd))
}
cat("\n\n")
}
}
return(invisible(rules))
},
createCompetitors = function(){
"Create competitors table"
fr <- .self$tree$frame
fr <- fr[fr$var != "<leaf>",]
sp <- .self$tree$splits
sp <- as.data.frame(sp)
sp$var <- row.names(sp)
row.names(sp) <- NULL
sp$path <- rep(as.numeric(row.names(fr)), (fr$ncompete+fr$nsurrogate+1))
sp$string <- paste(sp$var, ifelse(sp$ncat == -1L, "<", ">="), round(sp$index, digits = 3))
sp <- with(sp, sp[adj==0, ])
sp <- with(sp, sp[, -5])
sp.2 <- sp.3 <- sp
sp.2$path <- sp$path*2
sp.2$string <- paste(sp.2$var, ifelse(sp.2$ncat == -1L, "<", ">="), round(sp.2$index, digits = 3))
sp.3$path <- sp$path*2+1
sp.3$string <- paste(sp.3$var, ifelse(sp.3$ncat == -1L, ">=", "<"), round(sp.3$index, digits = 3))
.self$competitors <- rbind(sp.2, sp.3)
return(invisible(.self$competitors))
},
getIncidences = function(rule, rr.snd = T){
"Return incidence of the rule"
return(VT.incidences(.self$vt.difft, rule, rr.snd))
},
getAhatIncidence = function(){
"Return Ahat incidence"
if(sum(.self$Ahat)!=0){
table.inc <- VT.incidences(vt.difft = .self$vt.difft, select = .self$Ahat, F)
table.A <- table.inc$table.selected
table.A.cmpl <- table.inc$table.not.selected
cat(sprintf("Incidence in subgroup A\n"))
print(table.A$table)
cat("\n")
cat(sprintf("Relative risk : %0.3f \n\n", table.A$risque_relatif))
cat(sprintf("Incidence in complement subgroup of A\n"))
print(table.A.cmpl$table)
cat("\n")
cat(sprintf("Relative risk : %0.3f \n\n", table.A.cmpl$risque_relatif))
}else{
return("Empty set")
}
},
getAhatQuality = function(){
"Return Ahat quality"
resub <- vt.getQAOriginal(.self$Ahat, response = .self$vt.difft$vt.object$getY(), trt = .self$vt.difft$vt.object$data[, 2])
snd <- vt.getQAOriginal(.self$Ahat, response = .self$vt.difft$twin1, trt = .self$vt.difft$vt.object$data[, 2])
# on ajoute la taille de Ahat
size <- sum(.self$Ahat)
res <- cbind(size, resub, snd)
names(res) <- c("size", "resub", "snd")
return(res)
}
)
)