Github user felixcheung commented on a diff in the pull request:
https://github.com/apache/spark/pull/16951#discussion_r101454231
--- Diff: R/pkg/R/stats.R ---
@@ -149,15 +149,18 @@ setMethod("freqItems", signature(x =
"SparkDataFrame", cols = "character"),
#' This method implements a variation of the Greenwald-Khanna algorithm
(with some speed
#' optimizations). The algorithm was first present in
[[http://dx.doi.org/10.1145/375663.375670
#' Space-efficient Online Computation of Quantile Summaries]] by Greenwald
and Khanna.
+#' Note that rows containing any NA values will be removed before
calculation.
#'
#' @param x A SparkDataFrame.
-#' @param col The name of the numerical column.
+#' @param cols The names of the numerical columns.
#' @param probabilities A list of quantile probabilities. Each number must
belong to [0, 1].
#' For example 0 is the minimum, 0.5 is the median, 1
is the maximum.
#' @param relativeError The relative target precision to achieve (>= 0).
If set to zero,
#' the exact quantiles are computed, which could be
very expensive.
#' Note that values greater than 1 are accepted but
give the same result as 1.
-#' @return The approximate quantiles at the given probabilities.
+#' @return The approximate quantiles at the given probabilities. The
output should be a list,
+#' and each element in it is a list of numeric values which
represents the approximate
+#' quantiles in corresponding column.
--- End diff --
another alternative is to convert the results back into a vector of length
1 iff cols is length of 1, which matches the previous behavior
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org
For additional commands, e-mail: reviews-h...@spark.apache.org
