Avoid unnecessary creation of temporary objects.

InnerDetector/InDetRecEvent/SiSPSeededTrackFinderData/SiSPSeededTrackFinderData/SiTrajectoryElement_xk.h

 /*
-  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
 */
 
 /////////////////////////////////////////////////////////////////////////////////
@@ -135,6 +135,12 @@ namespace InDet{
       const Trk::PatternTrackParameters& parametersUB() const {return m_parametersUpdatedBackward;} 
       const Trk::PatternTrackParameters& parametersSM() const {return m_parametersSM;} 
 
+      /** @brief return pattern parameters matching the status of this element
+        * @return nullptr or pointer to the internal pattern track parameters PF, UF, PB, UB, SM depending on m_status and m_cluster
+        * The returned pointer is owned by this element.
+       */
+      const Trk::PatternTrackParameters* parameters() const;
+
       const Trk::Surface*  surface()  const {return m_surface;}
       const InDet::SiClusterLink_xk& linkF (int i) const {return m_linkForward[i];}
       const InDet::SiClusterLink_xk& linkB (int i) const {return m_linkBackward[i];}

InnerDetector/InDetRecEvent/SiSPSeededTrackFinderData/SiSPSeededTrackFinderData/SiTrajectoryElement_xk.icc

@@ -769,3 +769,30 @@ void InDet::SiTrajectoryElement_xk::CloseClusterSeach
   m_cluster = m_linkForward[0].cluster();
   m_xi2Forward    = m_linkForward[0].xi2    ();
 }
+
+
+inline const Trk::PatternTrackParameters *
+InDet::SiTrajectoryElement_xk::parameters() const
+{
+  // logic from SiTrajectoryElement_xk::trackParameters(bool, int Q) with Q==1
+
+  if (m_status == 1) {
+    if (m_cluster) {
+      return &m_parametersUpdatedForward;
+    } else {
+      return &m_parametersPredForward;
+    }
+  } else if (m_status == 2) {
+    if (m_cluster) {
+      return &m_parametersUpdatedBackward;
+    } else {
+      return &m_parametersPredBackward;
+    }
+  } else if (m_status == 3) {
+    if (m_cluster) {
+      return &m_parametersUpdatedBackward;
+    }
+  }
+  return nullptr;
+}
+

InnerDetector/InDetRecEvent/SiSPSeededTrackFinderData/SiSPSeededTrackFinderData/SiTrajectory_xk.h

 /*
-  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
 */
 
 /////////////////////////////////////////////////////////////////////////////////
@@ -113,6 +113,13 @@ namespace InDet{
       bool filterWithPreciseClustersError();
       bool backwardSmoother (bool);
       bool isLastPixel      ();
+
+      /** @brief Return the pattern track parameters of the first element of this trajectory matching its status
+       * @return nullptr or a pointer to the element owned pattern track parameters matching the current status
+       *   of the trajectory element.
+       */
+      const Trk::PatternTrackParameters *firstParameters();
+
       std::unique_ptr<Trk::TrackParameters> firstTrackParameters();
       void getClusters(std::list<const InDet::SiCluster*>&);
 

InnerDetector/InDetRecEvent/SiSPSeededTrackFinderData/SiSPSeededTrackFinderData/SiTrajectory_xk.icc

 /*
-  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
 */
 
 #include "TrkSurfaces/PlaneSurface.h"
@@ -70,6 +70,10 @@ inline bool InDet::SiTrajectory_xk::isLastPixel()
   return false;
 } 
 
+inline const Trk::PatternTrackParameters *InDet::SiTrajectory_xk::firstParameters() {
+  return m_elements[m_elementsMap[m_firstElement]].parameters();
+}
+
 inline std::unique_ptr<Trk::TrackParameters> InDet::SiTrajectory_xk::firstTrackParameters()
 {
   return m_elements[m_elementsMap[m_firstElement]].trackParameters(false,1);

InnerDetector/InDetRecTools/SiCombinatorialTrackFinderTool_xk/src/SiCombinatorialTrackFinder_xk.cxx

@@ -104,8 +104,7 @@ StatusCode InDet::SiCombinatorialTrackFinder_xk::initialize()
   ATH_CHECK( m_fieldCondObjInputKey.initialize() );
   ATH_CHECK( m_pixelDetElStatus.initialize( !m_pixelDetElStatus.empty() && m_usePIX) );
   ATH_CHECK( m_sctDetElStatus.initialize( !m_sctDetElStatus.empty() && m_useSCT) );
-  auto ptCutVal = m_minPtCut.value();
-  m_minPt2Cut = ptCutVal * ptCutVal;
+  m_minPt2Cut = std::pow(m_minPtCut.value(),2);
   return StatusCode::SUCCESS;
 }
 
@@ -803,14 +802,13 @@ InDet::SiCombinatorialTrackFinder_xk::EStat_t InDet::SiCombinatorialTrackFinder_
 
 Trk::Track* InDet::SiCombinatorialTrackFinder_xk::convertToTrack(SiCombinatorialTrackFinderData_xk& data) const
 {
-  std::unique_ptr<Trk::TrackParameters> param = data.trajectory().firstTrackParameters();
+  const Trk::PatternTrackParameters *param = data.trajectory().firstParameters();
   if (param) {
-     auto momentum = param->momentum();
-     const auto  pt2 = momentum.perp2();
+     double pt = param->transverseMomentum();
      // reject tracks with small pT
      // The cut should be large enough otherwise eta computation of such tracks may yield NANs.
-     if (pt2 < m_minPt2Cut) {
-        ATH_MSG_DEBUG( "Reject low pT track (pT = " << std::sqrt(pt2) << " < " << m_minPtCut.value() << ")");
+     if (pt < m_minPtCut.value()) {
+        ATH_MSG_DEBUG( "Reject low pT track (pT = " << pt << " < " << m_minPtCut.value() << ")");
         return nullptr;
      }
   }

Tracking/TrkEvent/TrkPatternParameters/TrkPatternParameters/PatternTrackParameters.h

 /*
-  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
 */
 
 /////////////////////////////////////////////////////////////////////////////////
@@ -62,6 +62,7 @@ namespace Trk {
       double           cosTheta          ()     const;
       double           cotTheta          ()     const;
       void             changeDirection   ()          ;
+      double           transverseMomentum()     const;
 
       virtual Amg::Vector3D position() const override final;
       virtual Amg::Vector3D momentum() const override final;
@@ -150,7 +151,8 @@ namespace Trk {
 
       Amg::Vector3D calculatePosition(void) const;
       Amg::Vector3D calculateMomentum(void) const;
-      
+      double        absoluteMomentum() const;
+
       private:
         std::string to_string() const;
     };
@@ -362,7 +364,7 @@ namespace Trk {
       } else {
         return -1.0;
       }
-    }	
+    }
 
   inline double         PatternTrackParameters::sinPhi        () const
     {
@@ -393,6 +395,19 @@ namespace Trk {
     {
       return calculateMomentum();
     }
+
+  inline double        PatternTrackParameters::absoluteMomentum() const
+    {
+       return m_parameters[4] != 0. ? 1. / std::abs(m_parameters[4]) : 10e9;
+    }
+
+  inline double        PatternTrackParameters::transverseMomentum() const
+    {
+       double p = absoluteMomentum();
+       double Se = std::sin(m_parameters[3]);
+       return p * Se;
+    }
+
 } // end of name space
 
 #endif // PatternTrackParameters

Tracking/TrkEvent/TrkPatternParameters/src/PatternTrackParameters.cxx

 /*
-  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
 */
 
 /////////////////////////////////////////////////////////////////////////////////
@@ -501,7 +501,7 @@ Amg::Vector3D Trk::PatternTrackParameters::calculatePosition(void) const {
 }
 
 Amg::Vector3D Trk::PatternTrackParameters::calculateMomentum(void) const {
-  double p = m_parameters[4] != 0. ? 1. / std::abs(m_parameters[4]) : 10e9;
+  double p = absoluteMomentum();
 
   double Sf = std::sin(m_parameters[2]), Cf = std::cos(m_parameters[2]);
   double Se = std::sin(m_parameters[3]), Ce = std::cos(m_parameters[3]);