|
|
|
00001 #include "RecoPixelVertexing/PixelVertexFinding/interface/PVPositionBuilder.h" 00002 #include <cmath> 00003 00005 PVPositionBuilder::PVPositionBuilder() {} 00006 00007 Measurement1D PVPositionBuilder::average(const reco::TrackRefVector &trks) const { 00008 // Cut and paste (more or less) from same class in ORCA framework 00009 double ntracks = double(trks.size()); 00010 if (ntracks==0) return Measurement1D ( 0. , 0. ); 00011 double sumZIP = 0; 00012 double err = 0; 00013 for (unsigned int i=0; i<trks.size(); i++) { 00014 sumZIP += trks[i]->dz(); // Z at IP 00015 err += trks[i]->dzError(); // error on Z at IP (I hope). Fix d.k. 00016 } 00017 return Measurement1D ( sumZIP/ntracks, err/ntracks/std::sqrt(ntracks) ); 00018 00019 } 00020 00021 Measurement1D PVPositionBuilder::wtAverage(const reco::TrackRefVector &trks) const { 00022 double ntracks = double(trks.size()); 00023 if (ntracks==0) return Measurement1D ( 0.0 , 0.0 ); 00024 double sumUp = 0; 00025 double sumDown = 0; 00026 double err = 0; 00027 for (unsigned int i=0; i<trks.size(); i++) { 00028 // double err2 = trks[i]->covariance(3,3); // error on Z at IP (I hope) 00029 double err2 = trks[i]->dzError(); // Fix d.k. 00030 err2 *= err2; 00031 if (err2 != 0){ 00032 sumUp += trks[i]->dz() * 1/err2; // error-weighted average of Z at IP 00033 sumDown += 1/err2; 00034 } 00035 err += std::sqrt( err2 ); 00036 } 00037 if (sumDown > 0) return Measurement1D ( sumUp/sumDown , err/ntracks/sqrt(ntracks) ); 00038 else return Measurement1D ( 0.0 , 0.0 ); 00039 }
1.7.3