File indexing completed on 2024-04-06 12:28:29
0001 #include "PixelVertexProducerMedian.h"
0002
0003 #include "FWCore/Framework/interface/MakerMacros.h"
0004 #include "FWCore/Framework/interface/ESHandle.h"
0005 #include "FWCore/Framework/interface/Frameworkfwd.h"
0006 #include "FWCore/Framework/interface/Event.h"
0007
0008 #include "DataFormats/TrackReco/interface/Track.h"
0009 #include "DataFormats/TrackReco/interface/TrackFwd.h"
0010
0011 #include "DataFormats/VertexReco/interface/Vertex.h"
0012 #include "DataFormats/VertexReco/interface/VertexFwd.h"
0013
0014 #include <fstream>
0015 #include <iostream>
0016 #include <vector>
0017 #include <algorithm>
0018
0019 #include "TROOT.h"
0020 #include "TH1F.h"
0021 #include "TF1.h"
0022
0023
0024 struct ComparePairs {
0025 bool operator()(const reco::Track* t1, const reco::Track* t2) { return (t1->vz() < t2->vz()); };
0026 };
0027
0028
0029 PixelVertexProducerMedian::PixelVertexProducerMedian(const edm::ParameterSet& ps) : theConfig(ps) {
0030 thePtMin = theConfig.getParameter<double>("PtMin");
0031 produces<reco::VertexCollection>();
0032 }
0033
0034
0035 PixelVertexProducerMedian::~PixelVertexProducerMedian() {}
0036
0037
0038 void PixelVertexProducerMedian::produce(edm::StreamID, edm::Event& ev, const edm::EventSetup& es) const {
0039
0040 edm::Handle<reco::TrackCollection> trackCollection;
0041 std::string trackCollectionName = theConfig.getParameter<std::string>("TrackCollection");
0042 ev.getByLabel(trackCollectionName, trackCollection);
0043 const reco::TrackCollection tracks_ = *(trackCollection.product());
0044
0045
0046 std::vector<const reco::Track*> tracks;
0047 for (unsigned int i = 0; i < tracks_.size(); i++) {
0048 if (tracks_[i].pt() > thePtMin) {
0049 reco::TrackRef recTrack(trackCollection, i);
0050 tracks.push_back(&(*recTrack));
0051 }
0052 }
0053
0054 LogTrace("MinBiasTracking") << " [VertexProducer] selected tracks: " << tracks.size() << " (out of " << tracks_.size()
0055 << ")";
0056
0057 auto vertices = std::make_unique<reco::VertexCollection>();
0058
0059 if (!tracks.empty()) {
0060
0061 std::sort(tracks.begin(), tracks.end(), ComparePairs());
0062
0063
0064 float med;
0065 if (tracks.size() % 2 == 0)
0066 med = (tracks[tracks.size() / 2 - 1]->vz() + tracks[tracks.size() / 2]->vz()) / 2;
0067 else
0068 med = tracks[tracks.size() / 2]->vz();
0069
0070 LogTrace("MinBiasTracking") << " [vertex position] median = " << med << " cm";
0071
0072 if (tracks.size() > 10) {
0073
0074 int nBin = 100;
0075 float halfWidth = 0.1;
0076
0077
0078 TH1F histo("histo", "histo", nBin, -halfWidth, halfWidth);
0079
0080 for (std::vector<const reco::Track*>::const_iterator track = tracks.begin(); track != tracks.end(); track++)
0081 if (fabs((*track)->vz() - med) < halfWidth)
0082 histo.Fill((*track)->vz() - med);
0083
0084 LogTrace("MinBiasTracking") << " [vertex position] most prob = "
0085 << med + histo.GetBinCenter(histo.GetMaximumBin()) << " cm";
0086
0087
0088 histo.Sumw2();
0089
0090 TF1 f1("f1", "[0]*exp(-0.5 * ((x-[1])/[2])^2) + [3]");
0091 f1.SetParameters(10., 0., 0.01, 1.);
0092
0093 histo.Fit(&f1, "QN");
0094
0095 LogTrace("MinBiasTracking") << " [vertex position] fitted = " << med + f1.GetParameter(1) << " +- "
0096 << f1.GetParError(1) << " cm";
0097
0098
0099 reco::Vertex::Error err;
0100 err(2, 2) = f1.GetParError(1) * f1.GetParError(1);
0101 reco::Vertex ver(reco::Vertex::Point(0, 0, med + f1.GetParameter(1)), err, 0, 1, 1);
0102 vertices->push_back(ver);
0103 } else {
0104
0105 reco::Vertex::Error err;
0106 err(2, 2) = 0.1 * 0.1;
0107 reco::Vertex ver(reco::Vertex::Point(0, 0, med), err, 0, 1, 1);
0108 vertices->push_back(ver);
0109 }
0110 }
0111 ev.put(std::move(vertices));
0112 }