Improve performance by initializing the channel vector in the header

Instead of initilazing the spadic channel vector with each function call,
 it is now initialized as member variable in the header.

core/detectors/trd/CbmTrdParSpadic.cxx

@@ -189,10 +189,8 @@ Int_t CbmTrdParSpadic::GetAsicChAddress(const Int_t asicChannel) {
 
   Int_t address = -1;
   // Channel mapping based on channels 0-15 on the odd eLink and 16-31 on the even eLink, check setting in the unpacker for your dataset
-  std::vector<Int_t> chvec = {23, 7,  22, 6,  21, 19, 5,  20, 18, 4,  3,
-                              17, 16, 2,  1,  0,  31, 30, 29, 15, 14, 28,
-                              27, 13, 11, 26, 12, 10, 25, 9,  24, 8};
-  address                  = chvec.at(asicChannel);
+
+  address = fVecSpadicChannels.at(asicChannel);
   return address;
 }
 

core/detectors/trd/CbmTrdParSpadic.h

@@ -78,8 +78,12 @@ private:
   static Double_t fgSizeY;  ///< SPADIC half size in y [cm]
   static Double_t fgSizeZ;  ///< SPADIC half size in z [cm]
 
+  const std::vector<Int_t> fVecSpadicChannels = {
+    23, 7,  22, 6,  21, 19, 5,  20, 18, 4,  3,  17, 16, 2, 1,  0,
+    31, 30, 29, 15, 14, 28, 27, 13, 11, 26, 12, 10, 25, 9, 24, 8};
 
-  ClassDef(CbmTrdParSpadic, 1)  // Definition of SPADIC ASIC parameters
+
+  ClassDef(CbmTrdParSpadic, 2)  // Definition of SPADIC ASIC parameters
 };
 
 #endif