Release the TPC distortion corrections after the recalculation

This frees memory in the TPC digitizer that is not needed after the recalculation of the scaled distortions.

- The digitizer only uses the global distortions of the main map.
- The global corrections of the main and the derivative map are now released after the recalculation.

https://its.cern.ch/jira/browse/O2-7309

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: sawenzel

Detectors/TPC/simulation/src/Digitizer.cxx

@@ -274,6 +274,9 @@ void Digitizer::recalculateDistortions()
     }
     // set new lumi of avg map
     mSpaceCharge->setMeanLumi(CorrMapParam::Instance().lumiInst);
+    // the corrections were only needed to compute the scaled distortions
+    mSpaceCharge->releaseGlobalCorrections();
+    mSpaceChargeDer->releaseGlobalCorrections();
   } else {
     LOGP(info, "Inst. lumi {} is same as mean lumi {}. Skip recalculation of distortions", CorrMapParam::Instance().lumiInst, mSpaceCharge->getMeanLumi());
   }

Detectors/TPC/spacecharge/include/TPCSpaceCharge/SpaceCharge.h

@@ -638,6 +638,9 @@ class SpaceCharge
   /// \param side side of the TPC
   void setDistortionLookupTables(const DataContainer& distdZ, const DataContainer& distdR, const DataContainer& distdRPhi, const Side side);
 
+  /// release the memory of the global corrections of both sides
+  void releaseGlobalCorrections();
+
   /// set the density, potential, electric fields, local distortions/corrections, global distortions/corrections from a file. Missing objects in the file are ignored.
   /// \param file output file where the electrical fields will be written to
   /// \param side of the TPC

Detectors/TPC/spacecharge/src/SpaceCharge.cxx

@@ -2126,6 +2126,16 @@ void SpaceCharge<DataT>::init()
   }
 }
 
+template <typename DataT>
+void SpaceCharge<DataT>::releaseGlobalCorrections()
+{
+  for (int iside = 0; iside < FNSIDES; ++iside) {
+    mGlobalCorrdR[iside] = DataContainer();
+    mGlobalCorrdZ[iside] = DataContainer();
+    mGlobalCorrdRPhi[iside] = DataContainer();
+  }
+}
+
 template <typename DataT>
 void SpaceCharge<DataT>::setDistortionLookupTables(const DataContainer& distdZ, const DataContainer& distdR, const DataContainer& distdRPhi, const Side side)
 {