From 4ff94e6ebdce7650e2c9b72e912724aca34e39dc Mon Sep 17 00:00:00 2001
From: shahoian <ruben.shahoyan@cern.ch>
Date: Wed, 29 Jul 2026 16:53:28 +0200
Subject: [PATCH] Add protection for fastTAtan2(0,0) call

---
 Common/MathUtils/include/MathUtils/detail/trigonometric.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Common/MathUtils/include/MathUtils/detail/trigonometric.h b/Common/MathUtils/include/MathUtils/detail/trigonometric.h
index 68d002320df2e..e13d965663dc9 100644
--- a/Common/MathUtils/include/MathUtils/detail/trigonometric.h
+++ b/Common/MathUtils/include/MathUtils/detail/trigonometric.h
@@ -298,10 +298,10 @@ GPUhdi() constexpr T fastATan2(T y, T x)
     T tan = 0;
     if (xx < 0) { // p1 is in the range [Pi/4, 3*Pi/4]
       phi0 = Pi075;
-      tan = -x1 / y1;
+      tan = y1 > T(0) ? -x1 / y1 : T(0); // yy is always >=0, hence y1>=0
     } else { // p1 is in the range [-Pi/4, Pi/4]
       phi0 = Pi025;
-      tan = y1 / x1;
+      tan = x1 > T(0) ? y1 / x1 : T(0);
     }
     return phi0 + atan(tan);
   };