Fix problem with empty PsdHits

Create and store matches for the psd detector system.

The ideal event builder relies on existing match objects. If the matches are
not available the detector system is excluded from the event building such
that at later stages no digis for this detector system ar present and no hits
are produced.

Fixes #2665.

sim/detectors/psd/CbmPsdSimpleDigitizer.cxx

@@ -9,6 +9,8 @@
 // -------------------------------------------------------------------------
 #include "CbmPsdSimpleDigitizer.h"
 
+#include "CbmLink.h"
+#include "CbmMatch.h"
 #include "CbmPsdDigi.h"
 #include "CbmPsdPoint.h"
 
@@ -57,9 +59,6 @@ CbmPsdSimpleDigitizer::~CbmPsdSimpleDigitizer() {}
 InitStatus CbmPsdSimpleDigitizer::Init()
 {
 
-  // Matches are not produced
-  fCreateMatches = kFALSE;
-
   // Get RootManager
   FairRootManager* ioman = FairRootManager::Instance();
   assert(ioman),
@@ -101,35 +100,40 @@ void CbmPsdSimpleDigitizer::Exec(Option_t*)
   Int_t modID        = -1;  // module ID
   Int_t scinID       = -1;  // #sciillator
   Int_t sec;
-  std::map<UInt_t, CbmPsdDigi> fired_digis_map;  // map<UInt_t uAddress, CbmPsdDigi>
+  std::map<UInt_t, std::pair<CbmPsdDigi, CbmMatch*>> fired_digis_map;  //store Digis and Matches for each module
 
   for (Int_t iPoint = 0; iPoint < nPoints; iPoint++) {
     point = (CbmPsdPoint*) fPointArray->At(iPoint);
     if (!point) continue;
 
-    modID          = point->GetModuleID();    //marina  1-44 (45)
-    scinID         = point->GetDetectorID();  //1-60
-    Double_t eLoss = point->GetEnergyLoss();
-    Double_t pTime     = point->GetTime();
-    sec                = (Int_t)((scinID - 1) / 6) + 1;  //marina   1-10
-    UInt_t uAddress    = CbmPsdAddress::GetAddress(modID, sec);
+    CbmLink link(1., iPoint, fCurrentMCEntry, fCurrentInput);
+
+    modID           = point->GetModuleID();    //marina  1-44 (45)
+    scinID          = point->GetDetectorID();  //1-60
+    Double_t eLoss  = point->GetEnergyLoss();
+    Double_t pTime  = point->GetTime();
+    sec             = (Int_t)((scinID - 1) / 6) + 1;  //marina   1-10
+    UInt_t uAddress = CbmPsdAddress::GetAddress(modID, sec);
 
     auto it = fired_digis_map.find(uAddress);
     if (it != fired_digis_map.end()) {
       //this key exists
-      it->second.SetEdep(it->second.GetEdep() + eLoss);
-      if (pTime < it->second.GetTime()) it->second.SetTime(pTime);
+      it->second.first.SetEdep(it->second.first.GetEdep() + eLoss);
+      if (pTime < it->second.first.GetTime()) it->second.first.SetTime(pTime);
+      it->second.second->AddLink(link);
     }
     else {
       //this key is new
       CbmPsdDigi digi = CbmPsdDigi(uAddress, pTime, eLoss);
-      fired_digis_map.insert(std::make_pair(uAddress, digi));
+      CbmMatch* match = new CbmMatch();
+      match->AddLink(link);
+      fired_digis_map.insert(std::make_pair(uAddress, std::make_pair(digi, match)));
     }
   }  // Loop over MCPoints
 
   Int_t nDigis = 0;
   for (auto entry : fired_digis_map) {
-    Double_t eDep            = entry.second.GetEdep();
+    Double_t eDep            = entry.second.first.GetEdep();
     Double_t eLossMIP        = eDep / 0.005;  // 5MeV per MIP
     Double_t pixPerMIP       = 15.;           // 15 pix per MIP
     Double_t eLossMIPSmeared = gRandom->Gaus(eLossMIP * pixPerMIP, sqrt(eLossMIP * pixPerMIP)) / pixPerMIP;
@@ -137,12 +141,12 @@ void CbmPsdSimpleDigitizer::Exec(Option_t*)
     Double_t eNoise          = gRandom->Gaus(0, 15) / 50. * 0.005;
     eLossSmeared += eNoise;
     CbmPsdDigi* digi =
-      new CbmPsdDigi(entry.second.GetAddress(), entry.second.GetTime() + fCurrentEventTime, eLossSmeared);
-    SendData(digi->GetTime(), digi);
+      new CbmPsdDigi(entry.second.first.GetAddress(), entry.second.first.GetTime() + fCurrentEventTime, eLossSmeared);
+    SendData(digi->GetTime(), digi, entry.second.second);
     nDigis++;
-    LOG(debug1) << fName << ": Digi " << nDigis << " Time " << entry.second.GetTime() + fCurrentEventTime << " Section "
-                << entry.second.GetSectionID() << " Module " << entry.second.GetModuleID() << " energy "
-                << eLossSmeared;
+    LOG(debug1) << fName << ": Digi " << nDigis << " Time " << entry.second.first.GetTime() + fCurrentEventTime
+                << " Section " << entry.second.first.GetSectionID() << " Module " << entry.second.first.GetModuleID()
+                << " energy " << eLossSmeared;
   }
 
   // --- Event log