#' Compute the importance of variables (VIMP) statistic
#'
#' @param dynforest_obj dynforest_obj \code{dynforest} object
#' @param IBS.min (Only with survival outcome) Minimal time to compute the Integrated Brier Score. Default value is set to 0.
#' @param IBS.max (Only with survival outcome) Maximal time to compute the Integrated Brier Score. Default value is set to the maximal time-to-event found.
#' @param ncores Number of cores used to grow trees in parallel. Default value is the number of cores of the computer-1.
#' @param seed Seed to replicate results
#'
#' @importFrom methods is
#' @import doRNG
#'
#' @return \code{compute_vimp()} function returns a list with the following elements:\tabular{ll}{
#' \code{Inputs} \tab A list of 3 elements: \code{Longitudinal}, \code{Numeric} and \code{Factor}. Each element contains the names of the predictors \cr
#' \tab \cr
#' \code{Importance} \tab A list of 3 elements: \code{Longitudinal}, \code{Numeric} and \code{Factor}. Each element contains a numeric vector of VIMP statistic predictor in \code{Inputs} value \cr
#' \tab \cr
#' \code{tree_oob_err} \tab A numeric vector containing the OOB error for each tree needed to compute the VIMP statistic \cr
#' \tab \cr
#' \code{IBS.range} \tab A vector containing the IBS min and max \cr
#' }
#'
#' @export
#'
#' @seealso [dynforest()]
#'
#' @examples
#' \donttest{
#' data(pbc2)
#'
#' # Get Gaussian distribution for longitudinal predictors
#' pbc2$serBilir <- log(pbc2$serBilir)
#' pbc2$SGOT <- log(pbc2$SGOT)
#' pbc2$albumin <- log(pbc2$albumin)
#' pbc2$alkaline <- log(pbc2$alkaline)
#'
#' # Sample 100 subjects
#' set.seed(1234)
#' id <- unique(pbc2$id)
#' id_sample <- sample(id, 100)
#' id_row <- which(pbc2$id%in%id_sample)
#'
#' pbc2_train <- pbc2[id_row,]
#'
# Build longitudinal data
#' timeData_train <- pbc2_train[,c("id","time",
#' "serBilir","SGOT",
#' "albumin","alkaline")]
#'
#' # Create object with longitudinal association for each predictor
#' timeVarModel <- list(serBilir = list(fixed = serBilir ~ time,
#' random = ~ time),
#' SGOT = list(fixed = SGOT ~ time + I(time^2),
#' random = ~ time + I(time^2)),
#' albumin = list(fixed = albumin ~ time,
#' random = ~ time),
#' alkaline = list(fixed = alkaline ~ time,
#' random = ~ time))
#'
#' # Build fixed data
#' fixedData_train <- unique(pbc2_train[,c("id","age","drug","sex")])
#'
#' # Build outcome data
#' Y <- list(type = "surv",
#' Y = unique(pbc2_train[,c("id","years","event")]))
#'
#' # Run dynforest function
#' res_dyn <- dynforest(timeData = timeData_train, fixedData = fixedData_train,
#' timeVar = "time", idVar = "id",
#' timeVarModel = timeVarModel, Y = Y,
#' ntree = 50, nodesize = 5, minsplit = 5,
#' cause = 2, ncores = 2, seed = 1234)
#'
#' # Compute VIMP statistic
#' res_dyn_VIMP <- compute_vimp(dynforest_obj = res_dyn, ncores = 2, seed = 1234)
#'
#' }
compute_vimp <- function(dynforest_obj, IBS.min = 0, IBS.max = NULL,
ncores = NULL, seed = 1234){
if (!methods::is(dynforest_obj,"dynforest")){
cli_abort(c(
"{.var dynforest_obj} must be a dynforest object",
"x" = "You've supplied a {.cls {class(dynforest_obj)}} object"
))
}
if (dynforest_obj$type=="surv"){
if (is.null(IBS.max)){
IBS.max <- max(dynforest_obj$data$Y$Y[,1])
}
}
rf <- dynforest_obj
Longitudinal <- rf$data$Longitudinal
Numeric <- rf$data$Numeric
Factor <- rf$data$Factor
Y <- rf$data$Y
timeVar <- rf$timeVar
ntree <- ncol(rf$rf)
Inputs <- names(rf$Inputs[!sapply(rf$Inputs,is.null)])
# ncores
if (is.null(ncores)==TRUE){
ncores <- parallel::detectCores()-1
}
##############################
pbapply::pboptions(type="none")
cl <- parallel::makeCluster(ncores)
doParallel::registerDoParallel(cl)
pck <- .packages()
dir0 <- find.package()
dir <- sapply(1:length(pck),function(k){gsub(pck[k],"",dir0[k])})
parallel::clusterExport(cl,list("pck","dir"),envir=environment())
parallel::clusterEvalQ(cl,sapply(1:length(pck),function(k){require(pck[k],lib.loc=dir[k],character.only=TRUE)}))
tree_oob_err <- pbsapply(1:ntree,
FUN=function(i){OOB.tree(rf$rf[,i], Longitudinal = Longitudinal, Numeric = Numeric, Factor = Factor, Y = Y,
timeVar = timeVar, IBS.min = IBS.min, IBS.max = IBS.max, cause = rf$cause)},cl=cl)
parallel::stopCluster(cl)
# tree_oob_err <- rep(NA, ntree)
# for (i in 1:ntree){
# tree_oob_err[i] = OOB.tree(rf$rf[,i], Longitudinal=Longitudinal,Numeric=Numeric,Factor = Factor, Y=Y,
# IBS.min = IBS.min, IBS.max = IBS.max, cause = rf$cause)
# }
#####################
Longitudinal.perm <- Longitudinal
Numeric.perm <- Numeric
Factor.perm <- Factor
p <- NULL
Importance.Longitudinal <- NULL
Importance.Numeric <- NULL
Importance.Factor <- NULL
if (is.element("Longitudinal",Inputs)==TRUE){
Longitudinal.err <- matrix(NA, ntree, ncol(Longitudinal$X))
cl <- parallel::makeCluster(ncores)
doParallel::registerDoParallel(cl)
pck <- .packages()
dir0 <- find.package()
dir <- sapply(1:length(pck),function(k){gsub(pck[k],"",dir0[k])})
parallel::clusterExport(cl,list("pck","dir"),envir=environment())
parallel::clusterEvalQ(cl,sapply(1:length(pck),function(k){require(pck[k],lib.loc=dir[k],character.only=TRUE)}))
Importance.Longitudinal <- foreach::foreach(p=1:ncol(Longitudinal$X),
.combine = "c", .options.RNG = seed) %dorng% {
# for (p in 1:ncol(Longitudinal$X)){
Longitudinal.perm$X[,p] <- sample(x = na.omit(Longitudinal$X[,p]),
size = length(Longitudinal$X[,p]),
replace = TRUE) # avoid NA issue with permut
for (k in 1:ntree){
Longitudinal.err[k,p] <- OOB.tree(rf$rf[,k], Longitudinal = Longitudinal.perm, Numeric = Numeric, Factor = Factor, Y,
timeVar = timeVar, IBS.min = IBS.min, IBS.max = IBS.max, cause = rf$cause)
}
Longitudinal.perm$X[,p] <- Longitudinal$X[,p]
res <- mean(Longitudinal.err[,p]- tree_oob_err)
}
parallel::stopCluster(cl)
}
if (is.element("Numeric",Inputs)==TRUE){
Numeric.err <- matrix(NA, ntree, dim(Numeric$X)[2])
cl <- parallel::makeCluster(ncores)
doParallel::registerDoParallel(cl)
pck <- .packages()
dir0 <- find.package()
dir <- sapply(1:length(pck),function(k){gsub(pck[k],"",dir0[k])})
parallel::clusterExport(cl,list("pck","dir"),envir=environment())
parallel::clusterEvalQ(cl,sapply(1:length(pck),function(k){require(pck[k],lib.loc=dir[k],character.only=TRUE)}))
Importance.Numeric <- foreach::foreach(p=1:ncol(Numeric$X),
.combine = "c", .options.RNG = seed) %dorng% {
Numeric.perm$X[,p] <- sample(Numeric$X[,p])
# for (p in 1:ncol(Numeric$X)){
for (k in 1:ntree){
Numeric.err[k,p] <- OOB.tree(rf$rf[,k], Longitudinal = Longitudinal, Numeric = Numeric.perm, Factor = Factor, Y,
timeVar = timeVar, IBS.min = IBS.min, IBS.max = IBS.max, cause = rf$cause)
}
Numeric.perm$X[,p] <- Numeric$X[,p]
res <- mean(Numeric.err[,p]- tree_oob_err)
}
parallel::stopCluster(cl)
}
if (is.element("Factor",Inputs)==TRUE){
Factor.err <- matrix(NA, ntree, dim(Factor$X)[2])
cl <- parallel::makeCluster(ncores)
doParallel::registerDoParallel(cl)
pck <- .packages()
dir0 <- find.package()
dir <- sapply(1:length(pck),function(k){gsub(pck[k],"",dir0[k])})
parallel::clusterExport(cl,list("pck","dir"),envir=environment())
parallel::clusterEvalQ(cl,sapply(1:length(pck),function(k){require(pck[k],lib.loc=dir[k],character.only=TRUE)}))
Importance.Factor <- foreach::foreach(p=1:ncol(Factor$X),
.combine = "c", .options.RNG = seed) %dorng% {
Factor.perm$X[,p] <- sample(Factor$X[,p])
#for (p in 1:ncol(Factor$X)){
for (k in 1:ntree){
Factor.err[k,p] <- OOB.tree(rf$rf[,k], Longitudinal=Longitudinal, Numeric = Numeric, Factor=Factor.perm , Y,
timeVar = timeVar, IBS.min = IBS.min, IBS.max = IBS.max, cause = rf$cause)
}
Factor.perm$X[,p] <- Factor$X[,p]
res <- mean(Factor.err[,p]- tree_oob_err)
}
parallel::stopCluster(cl)
}
Importance <- list(Longitudinal=as.vector(Importance.Longitudinal), Numeric=as.vector(Importance.Numeric), Factor=as.vector(Importance.Factor))
out <- list(Inputs = dynforest_obj$Inputs,
Importance = Importance,
tree_oob_err = tree_oob_err,
IBS.range = c(IBS.min, IBS.max))
class(out) <- c("dynforestvimp")
return(out)
}
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.