From 082266ddaebe3ce7d12019fcff56f7b9d418b5f6 Mon Sep 17 00:00:00 2001 From: Stephan Hageboeck Date: Mon, 15 Sep 2025 17:20:20 +0200 Subject: [PATCH] [RDF][Docs] Explain that RDF uses Kahan sums for the mean. --- tree/dataframe/inc/ROOT/RDF/RInterface.hxx | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tree/dataframe/inc/ROOT/RDF/RInterface.hxx b/tree/dataframe/inc/ROOT/RDF/RInterface.hxx index 70c85ff84ac9f..8153f6dee9ded 100644 --- a/tree/dataframe/inc/ROOT/RDF/RInterface.hxx +++ b/tree/dataframe/inc/ROOT/RDF/RInterface.hxx @@ -2788,6 +2788,8 @@ public: /// /// If T is not specified, RDataFrame will infer it from the data and just-in-time compile the correct /// template specialization of this method. + /// Note that internally, the summations are executed with Kahan sums in double precision, irrespective + /// of the type of column that is read. /// /// This action is *lazy*: upon invocation of this method the calculation is /// booked but not executed. Also see RResultPtr.