From e5f2da86712870daac66d45cdff60247efcec22c Mon Sep 17 00:00:00 2001
From: s-kganz <ganzkeenan1@gmail.com>
Date: Wed, 23 Jun 2021 18:27:46 -0700
Subject: [PATCH] add disclaimer for ncores on Windows in tests, prevent
 SCUT_parallel example from triggering a warning

---
 R/scut.R                   | 7 ++++---
 man/SCUT.Rd                | 6 ++++--
 tests/testthat/test-scut.R | 7 ++-----
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/R/scut.R b/R/scut.R
index ad9a676..559db6d 100644
--- a/R/scut.R
+++ b/R/scut.R
@@ -105,7 +105,9 @@ SCUT <- function(data, cls_col, oversample = oversample_smote,
 #' @importFrom parallel detectCores mclapply
 #'
 #' @examples
-#' ret <- SCUT_parallel(wine, "type", ncores = 2, undersample = undersample_kmeans)
+#' # SCUT_parallel fires a warning if ncores > 1 on Windows and will run on
+#' # one core only.
+#' ret <- SCUT_parallel(wine, "type", ncores = 1, undersample = undersample_kmeans)
 #' table(ret$type)
 SCUT_parallel <- function(data, cls_col, ncores = detectCores() %/% 2,
                           oversample = oversample_smote,
@@ -115,8 +117,7 @@ SCUT_parallel <- function(data, cls_col, ncores = detectCores() %/% 2,
 
   # windows does not support mclapply, so we have to do this serially
   if (.Platform$OS.type == "windows") {
-    warning("SCUT_parallel is not supported on Windows and will run on
-             one core.")
+    warning("SCUT_parallel runs on one core only on Windows.")
     ncores <- 1
   }
 
diff --git a/man/SCUT.Rd b/man/SCUT.Rd
index ea25b3c..ab64a7f 100644
--- a/man/SCUT.Rd
+++ b/man/SCUT.Rd
@@ -43,7 +43,7 @@ SCUT_parallel(
 A dataframe with equal class distribution.
 }
 \description{
-This function balances multiclass training datasets. In a dataframe with \code{n} classes and \code{m} rows, the resulting dataframe will have \code{m / n} rows per class. \code{\link{SCUT_parallel}()} distributes each over/undersampling task across multiple cores. Speedup usually occurs only if there are many classes using one of the slower resampling techniques (e.g. \code{\link{undersample_mclust}()}).
+This function balances multiclass training datasets. In a dataframe with \code{n} classes and \code{m} rows, the resulting dataframe will have \code{m / n} rows per class. \code{\link{SCUT_parallel}()} distributes each over/undersampling task across multiple cores. Speedup usually occurs only if there are many classes using one of the slower resampling techniques (e.g. \code{\link{undersample_mclust}()}). Note that \code{\link{SCUT_parallel}()} will always run on one core on Windows.
 }
 \details{
 Custom functions can be used to perform under/oversampling (see the required signature below). Parameters represented by \code{...} should be passsed via \code{osamp_opts} or \code{usamp_opts} as a list.
@@ -54,7 +54,9 @@ ret <- SCUT(iris, "Species", undersample = undersample_hclust,
 ret2 <- SCUT(chickwts, "feed", undersample = undersample_kmeans)
 table(ret$Species)
 table(ret2$feed)
-ret <- SCUT_parallel(wine, "type", ncores = 2, undersample = undersample_kmeans)
+# SCUT_parallel fires a warning if ncores > 1 on Windows and will run on
+# one core only.
+ret <- SCUT_parallel(wine, "type", ncores = 1, undersample = undersample_kmeans)
 table(ret$type)
 }
 \references{
diff --git a/tests/testthat/test-scut.R b/tests/testthat/test-scut.R
index 1066a19..9ae4ca9 100644
--- a/tests/testthat/test-scut.R
+++ b/tests/testthat/test-scut.R
@@ -28,10 +28,7 @@ for (i in 1:length(undersamplers)) {
 
   test_that(paste(osamp, usamp, "(parallel) have equal class distribution"),
             {
-              # During R CMD check, doParallel sometimes fails to export the
-              # package to parallel workers on Windows. This is not a problem
-              # once the package is installed, so the parallel version is
-              # skipped on Windows.
+              # Skip to avoid triggering a warning on > 1 core
               skip_on_os("windows")
 
 
@@ -52,7 +49,7 @@ for (i in 1:length(undersamplers)) {
 if (.Platform$OS.type == "windows") {
   expect_warning(
     SCUT_parallel(wine, "type"),
-    regexp=""
+    regexp="SCUT_parallel runs on one core only on Windows."
   )
 }