Revert "copy covariance matrix rather than keep pointer in CubicStateInterpolationTraj"

This reverts commit 29e7b482

Tr/TrackKernel/TrackKernel/CubicStateInterpolationTraj.h

@@ -18,7 +18,7 @@
 
 namespace LHCb
 {
-  class CubicStateInterpolationTraj : public CubicStateVectorInterpolationTraj
+  class CubicStateInterpolationTraj : public  CubicStateVectorInterpolationTraj
   {
   public:
     /// Constructor from two states
@@ -40,14 +40,14 @@ namespace LHCb
     Gaudi::TrackSymMatrix covariance( double z ) const ;
 
     /// Calculate state at location z
-    State state(double z) const override final ;
+    State state(double z) const override;
 
     /// Clone this trajectory
     std::unique_ptr<Trajectory> clone() const override { return std::unique_ptr<Trajectory>(new CubicStateInterpolationTraj(*this)) ; }
 
   private:
-    Gaudi::TrackSymMatrix m_covbegin ; ///< Covariance at first state
-    Gaudi::TrackSymMatrix m_covend ;   ///< Covariance at second state
+    const Gaudi::TrackSymMatrix* m_covbegin = nullptr ; ///< Covariance at first state
+    const Gaudi::TrackSymMatrix* m_covend  = nullptr;   ///< Covariance at second state
   };
 
   /*************************************************************************************************/
@@ -58,7 +58,7 @@ namespace LHCb
   CubicStateInterpolationTraj::CubicStateInterpolationTraj(const LHCb::State& begin,const LHCb::State& end)
     :
     CubicStateVectorInterpolationTraj(begin,end),
-    m_covbegin(begin.covariance()), m_covend(end.covariance())
+    m_covbegin(&(begin.covariance())), m_covend(&(end.covariance()))
   {
   }
 
@@ -66,7 +66,7 @@ namespace LHCb
   CubicStateInterpolationTraj::CubicStateInterpolationTraj(const LHCb::State& state,const Gaudi::XYZVector& bfield)
     :
     CubicStateVectorInterpolationTraj(state,bfield),
-    m_covbegin(state.covariance()), m_covend(m_covbegin)
+    m_covbegin(&(state.covariance())), m_covend(m_covbegin)
   {
   }
 
@@ -74,15 +74,15 @@ namespace LHCb
   void CubicStateInterpolationTraj::init(const LHCb::State& begin,const LHCb::State& end)
   {
     CubicStateVectorInterpolationTraj::init(begin,end) ;
-    m_covbegin = begin.covariance() ;
-    m_covend   = end.covariance() ;
+    m_covbegin = &(begin.covariance()) ;
+    m_covend   = &(end.covariance()) ;
   }
 
   inline
   void CubicStateInterpolationTraj::init(const LHCb::State& state,const Gaudi::XYZVector& bfield)
   {
     CubicStateVectorInterpolationTraj::init(state,bfield) ;
-    m_covbegin = m_covend = state.covariance() ;
+    m_covbegin = m_covend = &(state.covariance()) ;
   }
 }