[R] Set number of threads in demos.

R-package/R/xgb.Booster.R

@@ -628,10 +628,15 @@ xgb.attributes <- function(object) {
 #'
 #' @examples
 #' data(agaricus.train, package='xgboost')
+#' ## Keep the number of threads to 2 for examples
+#' nthread <- 2
+#' data.table::setDTthreads(nthread)
 #' train <- agaricus.train
 #'
-#' bst <- xgboost(data = train$data, label = train$label, max_depth = 2,
-#' eta = 1, nthread = 2, nrounds = 2, objective = "binary:logistic")
+#' bst <- xgboost(
+#' data = train$data, label = train$label, max_depth = 2,
+#' eta = 1, nthread = nthread, nrounds = 2, objective = "binary:logistic"
+#' )
 #' config <- xgb.config(bst)
 #'
 #' @rdname xgb.config

R-package/R/xgb.DMatrix.R

@@ -18,7 +18,12 @@
 #'
 #' @examples
 #' data(agaricus.train, package='xgboost')
-#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
+#' ## Keep the number of threads to 2 for examples
+#' nthread <- 2
+#' data.table::setDTthreads(nthread)
+#' dtrain <- with(
+#' agaricus.train, xgb.DMatrix(data, label = label, nthread = nthread)
+#' )
 #' xgb.DMatrix.save(dtrain, 'xgb.DMatrix.data')
 #' dtrain <- xgb.DMatrix('xgb.DMatrix.data')
 #' if (file.exists('xgb.DMatrix.data')) file.remove('xgb.DMatrix.data')

R-package/R/xgb.model.dt.tree.R

@@ -46,9 +46,12 @@
 #' # Basic use:
 #'
 #' data(agaricus.train, package='xgboost')
+#' ## Keep the number of threads to 2 for examples
+#' nthread <- 2
+#' data.table::setDTthreads(nthread)
 #'
 #' bst <- xgboost(data = agaricus.train$data, label = agaricus.train$label, max_depth = 2,
-#' eta = 1, nthread = 2, nrounds = 2,objective = "binary:logistic")
+#' eta = 1, nthread = nthread, nrounds = 2,objective = "binary:logistic")
 #'
 #' (dt <- xgb.model.dt.tree(colnames(agaricus.train$data), bst))
 #'

R-package/R/xgb.plot.deepness.R

@@ -45,10 +45,13 @@
 #' @examples
 #'
 #' data(agaricus.train, package='xgboost')
+#' ## Keep the number of threads to 2 for examples
+#' nthread <- 2
+#' data.table::setDTthreads(nthread)
 #'
-#' # Change max_depth to a higher number to get a more significant result
+#' ## Change max_depth to a higher number to get a more significant result
 #' bst <- xgboost(data = agaricus.train$data, label = agaricus.train$label, max_depth = 6,
-#' eta = 0.1, nthread = 2, nrounds = 50, objective = "binary:logistic",
+#' eta = 0.1, nthread = nthread, nrounds = 50, objective = "binary:logistic",
 #' subsample = 0.5, min_child_weight = 2)
 #'
 #' xgb.plot.deepness(bst)

R-package/R/xgb.plot.importance.R

@@ -45,9 +45,14 @@
 #'
 #' @examples
 #' data(agaricus.train)
+#' ## Keep the number of threads to 2 for examples
+#' nthread <- 2
+#' data.table::setDTthreads(nthread)
 #'
-#' bst <- xgboost(data = agaricus.train$data, label = agaricus.train$label, max_depth = 3,
-#' eta = 1, nthread = 2, nrounds = 2, objective = "binary:logistic")
+#' bst <- xgboost(
+#' data = agaricus.train$data, label = agaricus.train$label, max_depth = 3,
+#' eta = 1, nthread = nthread, nrounds = 2, objective = "binary:logistic"
+#' )
 #'
 #' importance_matrix <- xgb.importance(colnames(agaricus.train$data), model = bst)
 #'

R-package/R/xgb.plot.multi.trees.R

@@ -43,10 +43,15 @@
 #' @examples
 #'
 #' data(agaricus.train, package='xgboost')
-#'
-#' bst <- xgboost(data = agaricus.train$data, label = agaricus.train$label, max_depth = 15,
-#' eta = 1, nthread = 2, nrounds = 30, objective = "binary:logistic",
-#' min_child_weight = 50, verbose = 0)
+#' ## Keep the number of threads to 2 for examples
+#' nthread <- 2
+#' data.table::setDTthreads(nthread)
+#'
+#' bst <- xgboost(
+#' data = agaricus.train$data, label = agaricus.train$label, max_depth = 15,
+#' eta = 1, nthread = nthread, nrounds = 30, objective = "binary:logistic",
+#' min_child_weight = 50, verbose = 0
+#' )
 #'
 #' p <- xgb.plot.multi.trees(model = bst, features_keep = 3)
 #' print(p)

R-package/R/xgb.plot.shap.R

@@ -74,9 +74,14 @@
 #' data(agaricus.train, package='xgboost')
 #' data(agaricus.test, package='xgboost')
 #'
-#' bst <- xgboost(agaricus.train$data, agaricus.train$label, nrounds = 50,
+#' ## Keep the number of threads to 2 for examples
+#' nthread <- 2
+#' data.table::setDTthreads(nthread)
+#' nrounds <- 20
+#'
+#' bst <- xgboost(agaricus.train$data, agaricus.train$label, nrounds = nrounds,
 #' eta = 0.1, max_depth = 3, subsample = .5,
-#' method = "hist", objective = "binary:logistic", nthread = 2, verbose = 0)
+#' method = "hist", objective = "binary:logistic", nthread = nthread, verbose = 0)
 #'
 #' xgb.plot.shap(agaricus.test$data, model = bst, features = "odor=none")
 #' contr <- predict(bst, agaricus.test$data, predcontrib = TRUE)
@@ -85,12 +90,11 @@
 #'
 #' # multiclass example - plots for each class separately:
 #' nclass <- 3
-#' nrounds <- 20
 #' x <- as.matrix(iris[, -5])
 #' set.seed(123)
 #' is.na(x[sample(nrow(x) * 4, 30)]) <- TRUE # introduce some missing values
 #' mbst <- xgboost(data = x, label = as.numeric(iris$Species) - 1, nrounds = nrounds,
-#' max_depth = 2, eta = 0.3, subsample = .5, nthread = 2,
+#' max_depth = 2, eta = 0.3, subsample = .5, nthread = nthread,
 #' objective = "multi:softprob", num_class = nclass, verbose = 0)
 #' trees0 <- seq(from=0, by=nclass, length.out=nrounds)
 #' col <- rgb(0, 0, 1, 0.5)

R-package/R/xgb.train.R

@@ -168,7 +168,8 @@
 #' than the \code{xgboost} interface.
 #'
 #' Parallelization is automatically enabled if \code{OpenMP} is present.
-#' Number of threads can also be manually specified via \code{nthread} parameter.
+#' Number of threads can also be manually specified via the \code{nthread}
+#' parameter.
 #'
 #' The evaluation metric is chosen automatically by XGBoost (according to the objective)
 #' when the \code{eval_metric} parameter is not provided.
@@ -237,17 +238,25 @@
 #' data(agaricus.train, package='xgboost')
 #' data(agaricus.test, package='xgboost')
 #'
-#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
-#' dtest <- with(agaricus.test, xgb.DMatrix(data, label = label, nthread = 2))
+#' ## Keep the number of threads to 2 for examples
+#' nthread <- 2
+#' data.table::setDTthreads(nthread)
+#'
+#' dtrain <- with(
+#' agaricus.train, xgb.DMatrix(data, label = label, nthread = nthread)
+#' )
+#' dtest <- with(
+#' agaricus.test, xgb.DMatrix(data, label = label, nthread = nthread)
+#' )
 #' watchlist <- list(train = dtrain, eval = dtest)
 #'
 #' ## A simple xgb.train example:
-#' param <- list(max_depth = 2, eta = 1, verbose = 0, nthread = 2,
+#' param <- list(max_depth = 2, eta = 1, verbose = 0, nthread = nthread,
 #' objective = "binary:logistic", eval_metric = "auc")
 #' bst <- xgb.train(param, dtrain, nrounds = 2, watchlist)
 #'
-#'
-#' ## An xgb.train example where custom objective and evaluation metric are used:
+#' ## An xgb.train example where custom objective and evaluation metric are
+#' ## used:
 #' logregobj <- function(preds, dtrain) {
 #' labels <- getinfo(dtrain, "label")
 #' preds <- 1/(1 + exp(-preds))
@@ -263,12 +272,12 @@
 #'
 #' # These functions could be used by passing them either:
 #' # as 'objective' and 'eval_metric' parameters in the params list:
-#' param <- list(max_depth = 2, eta = 1, verbose = 0, nthread = 2,
+#' param <- list(max_depth = 2, eta = 1, verbose = 0, nthread = nthread,
 #' objective = logregobj, eval_metric = evalerror)
 #' bst <- xgb.train(param, dtrain, nrounds = 2, watchlist)
 #'
 #' # or through the ... arguments:
-#' param <- list(max_depth = 2, eta = 1, verbose = 0, nthread = 2)
+#' param <- list(max_depth = 2, eta = 1, verbose = 0, nthread = nthread)
 #' bst <- xgb.train(param, dtrain, nrounds = 2, watchlist,
 #' objective = logregobj, eval_metric = evalerror)
 #'
@@ -278,7 +287,7 @@
 #'
 #'
 #' ## An xgb.train example of using variable learning rates at each iteration:
-#' param <- list(max_depth = 2, eta = 1, verbose = 0, nthread = 2,
+#' param <- list(max_depth = 2, eta = 1, verbose = 0, nthread = nthread,
 #' objective = "binary:logistic", eval_metric = "auc")
 #' my_etas <- list(eta = c(0.5, 0.1))
 #' bst <- xgb.train(param, dtrain, nrounds = 2, watchlist,
@@ -290,7 +299,7 @@
 #'
 #' ## An 'xgboost' interface example:
 #' bst <- xgboost(data = agaricus.train$data, label = agaricus.train$label,
-#' max_depth = 2, eta = 1, nthread = 2, nrounds = 2,
+#' max_depth = 2, eta = 1, nthread = nthread, nrounds = 2,
 #' objective = "binary:logistic")
 #' pred <- predict(bst, agaricus.test$data)
 #'