From e5d69ae49e7177c3e20de9a4ab8a445fd8b50559 Mon Sep 17 00:00:00 2001
From: Sebastian Krantz <sebastian.krantz@graduateinstitute.ch>
Date: Sat, 7 Sep 2024 13:35:50 +0200
Subject: [PATCH] Fix `fmean(c(1L, NA), na.rm = F, g = c(1L, 1L))` issue
 (#628).

---
 src/fmean.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/fmean.c b/src/fmean.c
index cea87e69..e5e5aa1e 100644
--- a/src/fmean.c
+++ b/src/fmean.c
@@ -208,7 +208,9 @@ void fmean_int_g_impl(double *restrict pout, const int *restrict px, const int n
     R_Free(n);
   } else {
     --pout;
-    for(int i = l; i--; ) pout[pg[i]] += px[i]; // Used to stop loop when all groups passed with NA, but probably no speed gain since groups are mostly ordered.
+    for(int i = l; i--; ) {
+      pout[pg[i]] += px[i] == NA_INTEGER ? NA_REAL : px[i]; // Used to stop loop when all groups passed with NA, but probably no speed gain since groups are mostly ordered.
+    }
     ++pout;
     for(int i = ng; i--; ) pout[i] /= pgs[i];
   }