From 6220b122ce93c5ff1d23094a99c1d7abe52d0590 Mon Sep 17 00:00:00 2001
From: Lucia Anna Tarasovicova <lucia.anna.husova@cern.ch>
Date: Tue, 12 Nov 2024 15:44:16 +0100
Subject: [PATCH] fix for the BC ID shift

---
 Modules/CTP/src/RawDataQcTask.cxx | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Modules/CTP/src/RawDataQcTask.cxx b/Modules/CTP/src/RawDataQcTask.cxx
index a1b2f79b05..c3c2599e88 100644
--- a/Modules/CTP/src/RawDataQcTask.cxx
+++ b/Modules/CTP/src/RawDataQcTask.cxx
@@ -226,11 +226,13 @@ void CTPRawDataReaderTask::monitorData(o2::framework::ProcessingContext& ctx)
           mHistoInputs->getNum()->Fill(i);
           mHistoInputRatios->getNum()->Fill(i);
           if (i == indexMB1 - 1) {
-            mHistoBCMinBias1->Fill((bcid - mShiftInput1) % 3564, 1. / mScaleInput1);
+            int bc = bcid - mShiftInput1 >= 0 ? bcid - mShiftInput1 : bcid - mShiftInput1 + 3564;
+            mHistoBCMinBias1->Fill(bc, 1. / mScaleInput1);
             mHistoInputRatios->getDen()->Fill(0., 1);
           }
           if (i == indexMB2 - 1) {
-            mHistoBCMinBias2->Fill((bcid - mShiftInput2) % 3564, 1. / mScaleInput2);
+            int bc = bcid - mShiftInput2 >= 0 ? bcid - mShiftInput2 : bcid - mShiftInput2 + 3564;
+            mHistoBCMinBias2->Fill(bc, 1. / mScaleInput2);
           }
         }
       }