PrimaryVertices abort fit when invChol fails

Event/RecEvent/src/PrimaryVertices.cpp

@@ -96,7 +96,7 @@ namespace LHCb::Event::PV {
     pv.setHalfDChi2DX( LinAlg::initialize_with_zeros<LHCb::LinAlg::Vec<double, 3>>() );
     pv.setCovMatrix( convertToSMatrix<double>( cov ) );
     pv.setSumOfWeights( accumulator.sumw );
-    bool converged = std::abs( delta( 2 ) ) < maxDeltaZConverged && abs( deltachi2 ) < maxDeltaChi2Converged;
+    bool converged = std::abs( delta.z() ) < maxDeltaZConverged && abs( deltachi2 ) < maxDeltaChi2Converged;
     return converged ? PVFitStatus::Converged : PVFitStatus::NotConverged;
   };
 
@@ -258,24 +258,26 @@ namespace LHCb::Event::PV {
     auto     status = PVFitStatus::NotConverged;
     auto     zcache = pv.position().z();
     unsigned iter{0};
-    for ( ; iter < fitconfig.maxFitIter && status == PVFitStatus::NotConverged; ++iter ) {
+    for ( ;
+          iter < fitconfig.maxFitIter && ( status == PVFitStatus::NotConverged || iter < fitconfig.numAnnealingSteps );
+          ++iter ) {
       // dumb 1-step annealing scheme. don't use for refits.
       const auto chi2maxmultiplier = std::max( int( fitconfig.numAnnealingSteps ) - int( iter ) + 1, 1 );
       const auto thischi2max       = chi2maxmultiplier * fitconfig.maxDeltaChi2;
 
       // Update the 2nd derivative cache only when vtx moved significantly, or on the first iteration
-      const auto maxDeltaZForCache = 0.2;
-      const auto vtxz              = pv.position().z();
-      if ( iter == 0 || std::abs( vtxz - zcache ) > maxDeltaZForCache ) {
-        status = fitSingleStep<true>( pv, pvtracks, thischi2max, fitconfig.maxDeltaZConverged,
-                                      fitconfig.maxDeltaChi2Converged );
-        zcache = vtxz;
-      } else {
-        status = fitSingleStep<false>( pv, pvtracks, thischi2max, fitconfig.maxDeltaZConverged,
-                                       fitconfig.maxDeltaChi2Converged );
+      constexpr auto maxDeltaZForCache  = 0.2 * Gaudi::Units::mm;
+      const auto     vtxz               = pv.position().z();
+      const auto     updateWeightMatrix = ( iter == 0 ) || ( std::abs( vtxz - zcache ) > maxDeltaZForCache );
+      status = updateWeightMatrix ? fitSingleStep<true>( pv, pvtracks, thischi2max, fitconfig.maxDeltaZConverged,
+                                                         fitconfig.maxDeltaChi2Converged )
+                                  : fitSingleStep<false>( pv, pvtracks, thischi2max, fitconfig.maxDeltaZConverged,
+                                                          fitconfig.maxDeltaChi2Converged );
+      if ( status == PVFitStatus::Failed ) {
+        pv.setStatus( status );
+        return status;
       }
-      // make sure to continue if still annealing
-      if ( status == PVFitStatus::Converged && iter < fitconfig.numAnnealingSteps ) status = PVFitStatus::NotConverged;
+      if ( updateWeightMatrix ) zcache = vtxz;
     }
     // To make sure that we can read back the same vertices from the persistency without storing everything,
     // we update once more the derivatives and weights