From b1e65172d0a10ae2d6e70e8464175fb04cedee6f Mon Sep 17 00:00:00 2001
From: Ian Tomalin <ian.tomalin@stfc.ac.uk>
Date: Sat, 23 Mar 2024 21:09:22 +0000
Subject: [PATCH] Andrews KF crash fix (#263)

---
 L1Trigger/TrackFindingTMTT/src/KFbase.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/L1Trigger/TrackFindingTMTT/src/KFbase.cc b/L1Trigger/TrackFindingTMTT/src/KFbase.cc
index c7e55f54adab9..afff3cbc7709c 100644
--- a/L1Trigger/TrackFindingTMTT/src/KFbase.cc
+++ b/L1Trigger/TrackFindingTMTT/src/KFbase.cc
@@ -551,7 +551,7 @@ namespace tmtt {
       matRinv = TMatrixD(TMatrixD::kInverted, matR);
     } else {
       // Protection against rare maths instability.
-      const TMatrixD unitMatrix(TMatrixD::kUnit, TMatrixD(nHelixPar_, nHelixPar_));
+      const TMatrixD unitMatrix(TMatrixD::kUnit, TMatrixD(2, 2));
       const double big = 9.9e9;
       matRinv = big * unitMatrix;
     }