From 2d030e689f61608b46ff13d14947a25766189149 Mon Sep 17 00:00:00 2001
From: =?utf8?q?J=C3=A9r=C3=B4me=20Benoit?= <jerome.benoit@piment-noir.org>
Date: Tue, 6 May 2025 23:21:13 +0200
Subject: [PATCH] fix(qav3): add inputs safeguard to zero_lag_series()
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Signed-off-by: Jérôme Benoit <jerome.benoit@piment-noir.org>
---
 quickadapter/user_data/strategies/Utils.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/quickadapter/user_data/strategies/Utils.py b/quickadapter/user_data/strategies/Utils.py
index 633e4c8..c19316c 100644
--- a/quickadapter/user_data/strategies/Utils.py
+++ b/quickadapter/user_data/strategies/Utils.py
@@ -127,7 +127,9 @@ def vwapb(dataframe: pd.DataFrame, window=20, num_of_std=1) -> tuple:
 
 def zero_lag_series(series: pd.Series, period: int) -> pd.Series:
     """Applies a zero lag filter to reduce MA lag."""
-    lag = int(0.5 * (period - 1))
+    lag = max(int(0.5 * (period - 1)), 0)
+    if lag == 0:
+        return series
     return 2 * series - series.shift(lag)
 
 
-- 
2.43.0