From 4453ae678ca837286b7dcd9f4663065bfa5e5e02 Mon Sep 17 00:00:00 2001
From: skowron <skowron@f7af4fe6-9843-0410-8265-dc069ae4e863>
Date: Sun, 7 Sep 2003 17:14:01 +0000
Subject: [PATCH] Additional Protection

---
 HBTAN/AliHBTPair.cxx | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/HBTAN/AliHBTPair.cxx b/HBTAN/AliHBTPair.cxx
index 1751a2ec3bf..fe6490be666 100644
--- a/HBTAN/AliHBTPair.cxx
+++ b/HBTAN/AliHBTPair.cxx
@@ -249,7 +249,16 @@ Double_t AliHBTPair::GetKStar()
     
     CalculateQInvL();
     
-    Q = TMath::Sqrt( Q*Q - fQInvL);
+    Q = Q*Q - fQInvL;
+    if ( Q < 0)
+     {
+        Info("GetKStar","Q = %f",Q);
+        fPart1->Print();
+        fPart2->Print();
+        Q = TMath::Abs(Q);
+     }
+     
+    Q = TMath::Sqrt(Q);
     fKStar = Q/2.;
     fKStarNotCalc = kFALSE;
    }
-- 
2.31.1