From ac16e4ac2a27a463ca3de28c7f322a468a4a5879 Mon Sep 17 00:00:00 2001
From: "se.gorbunov" <se.gorbunov@gsi.de>
Date: Thu, 20 Jan 2022 00:24:04 +0000
Subject: [PATCH] fix the calculation of a mc position at a given z
---
core/data/sts/CbmStsPoint.cxx | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/core/data/sts/CbmStsPoint.cxx b/core/data/sts/CbmStsPoint.cxx
index dda0d7a575..1d236862a4 100644
--- a/core/data/sts/CbmStsPoint.cxx
+++ b/core/data/sts/CbmStsPoint.cxx
@@ -90,8 +90,8 @@ CbmStsPoint::CbmStsPoint(const CbmStsPoint& point, int32_t eventId, double event
double CbmStsPoint::GetX(double z) const
{
// LOG(info) << fZ << " " << z << " " << fZ_out;
- if ((fZ_out - z) * (fZ - z) >= 0.) return (fX_out + fX) / 2.;
double dz = fZ_out - fZ;
+ if (fabs(dz) < 1.e-4) return 0.5 * (fX_out + fX);
return (fX + (z - fZ) / dz * (fX_out - fX));
}
// -------------------------------------------------------------------------
@@ -100,9 +100,8 @@ double CbmStsPoint::GetX(double z) const
// ----- Point y coordinate from linear extrapolation ------------------
double CbmStsPoint::GetY(double z) const
{
- if ((fZ_out - z) * (fZ - z) >= 0.) return (fY_out + fY) / 2.;
double dz = fZ_out - fZ;
- // if ( abs(dz) < 1.e-3 ) return (fY_out+fY)/2.;
+ if (fabs(dz) < 1.e-4) return 0.5 * (fY_out + fY);
return (fY + (z - fZ) / dz * (fY_out - fY));
}
// -------------------------------------------------------------------------
--
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