Enable possibility to specify a field object directly (e.g. CbmFieldConst) as...

Enable possibility to specify a field object directly (e.g. CbmFieldConst) as needed for mCBM. Refs #1300 @0.5 h

git-svn-id: https://subversion.gsi.de/cbmsoft/cbmroot/trunk@14689 5a1b234a-d7ce-0410-9a93-fd649a8fa65c

macro/mcbm/mcbm_transport.C

@@ -80,6 +80,7 @@ void mcbm_transport(Int_t nEvents = 10,
   run.SetParFileName(parFile);
   run.SetGeoFileName(geoFile);
   run.LoadSetup(setupName);
+  run.SetField(new CbmFieldConst());
   run.SetTarget(targetElement, targetThickness, targetDiameter,
 								targetPosX, targetPosY, targetPosZ,
 								targetRotY*TMath::DegToRad());

run/CbmTransport.cxx

@@ -49,6 +49,7 @@ using std::stringstream;
 CbmTransport::CbmTransport() :
   TNamed("CbmTransport", "Transport Run"),
   fSetup(CbmSetup::Instance()),
+	fField(nullptr),
   fTarget(),
   fEventGen(new CbmEventGenerator),
   fRun(new FairRunSim()),
@@ -613,9 +614,10 @@ void CbmTransport::Run(Int_t nEvents) {
 
   // --- Create the magnetic field
   LOG(INFO) << GetName() << ": Register magnetic field";
-  CbmFieldMap* magField = fSetup->CreateFieldMap();
-  assert(magField);
-  fRun->SetField(magField);
+  LOG(INFO) << fField;
+  if ( ! fField ) fField = fSetup->CreateFieldMap();
+  fField->Print("");
+  fRun->SetField(fField);
 
 
   // --- Initialise the event generator
@@ -652,7 +654,7 @@ void CbmTransport::Run(Int_t nEvents) {
   FairRuntimeDb* rtdb = fRun->GetRuntimeDb();
   CbmFieldPar* fieldPar =
       static_cast<CbmFieldPar*>(rtdb->getContainer("CbmFieldPar"));
-  fieldPar->SetParameters(magField);
+  fieldPar->SetParameters(fField);
   fieldPar->setChanged();
   FairParRootFileIo* parOut = new FairParRootFileIo(kTRUE);
   parOut->open(fParFileName.Data());

run/CbmTransport.h

@@ -18,6 +18,7 @@
 class TGeant3;
 class TGeant4;
 class TVirtualMC;
+class FairField;
 class FairGenerator;
 class FairRunSim;
 class CbmEventGenerator;
@@ -169,6 +170,16 @@ class CbmTransport : public TNamed
     void SetEngine(ECbmEngine engine) { fEngine = engine; }
 
 
+    /** @brief Set magnetic field
+     ** @param field  Pointer to FairField instance
+     **
+     ** By default, a field map corresponding to the magnet geometry
+     ** will be used. This can be overridden by specifying a field
+     ** object directly through this method.
+     **/
+    void SetField(FairField* field) { fField = field; }
+
+
     /** @brief Define geometry file name (output)
      ** @param name  Name for geometry file
      **
@@ -290,6 +301,7 @@ class CbmTransport : public TNamed
   private:
 
     CbmSetup* fSetup;
+    FairField* fField;  //!
     std::shared_ptr<CbmTarget> fTarget;  //!
     CbmEventGenerator* fEventGen;
     FairRunSim* fRun;