From 52b94f42c89fa562cead22d982faa045ba464d95 Mon Sep 17 00:00:00 2001
From: slaren <slarengh@gmail.com>
Date: Wed, 16 Aug 2023 00:25:59 +0200
Subject: [PATCH] add Bessel's correction to stdev calculation
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Co-authored-by: Johannes Gäßler <johannesg@5d6.de>
---
 examples/llama-bench/llama-bench.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/llama-bench/llama-bench.cpp b/examples/llama-bench/llama-bench.cpp
index edf19f285..7b75b3082 100755
--- a/examples/llama-bench/llama-bench.cpp
+++ b/examples/llama-bench/llama-bench.cpp
@@ -63,7 +63,7 @@ T stddev(const std::vector<T>& v) {
     }
     T mean = avg(v);
     T sq_sum = std::inner_product(v.begin(), v.end(), v.begin(), T(0));
-    T stdev = std::sqrt(sq_sum / (T)v.size() - mean * mean);
+    T stdev = std::sqrt(sq_sum / (T)(v.size() - 1) - mean * mean * (T)v.size() / (T)(v.size() - 1));
     return stdev;
 }