HepMC3 event record library
AnalysisExample.cc
1// -*- C++ -*-
2//
3// This file is part of HepMC
4// Copyright (C) 2014-2023 The HepMC collaboration (see AUTHORS for details)
5//
6#include "AnalysisExample.h"
7#include <limits>
8namespace HepMC3
9{
10HEPMC3_DECLARE_WRITER_FILE(AnalysisExample)
11HEPMC3_DECLARE_WRITER_STREAM(AnalysisExample)
12
13AnalysisExample::AnalysisExample(const std::string &filename,std::shared_ptr<GenRunInfo> /*run*/): m_file(filename),
14 m_stream(&m_file)
15{
16 if ( !m_file.is_open() ) {
17 HEPMC3_ERROR( "AnalysisExample: could not open output file: "<<filename )
18 }
19 m_sum_of_weights=0;
20 m_sum_of_weights2=0;
21 m_bins["rapidity"]=std::vector<double> {-std::numeric_limits<double>::infinity(), -5.0,-4.5,-4.0,-3.5,-3.0,-2.5,-2.0,-1.5,-1.0,-0.5,0.0,0.5,1.0,1.5,2.0,2.5,3.0,3.5,4.0,4.5,5.0,std::numeric_limits<double>::infinity()};
22 m_vals["rapidity"]=std::vector<double>(m_bins.at("rapidity").size()-1,0.0);
23 m_errs["rapidity"]=std::vector<double>(m_bins.at("rapidity").size()-1,0.0);
24}
25
26AnalysisExample::AnalysisExample(std::ostream &stream, std::shared_ptr<GenRunInfo> /*run*/)
27 : m_stream(&stream)
28{
31 m_bins["rapidity"]=std::vector<double> {-std::numeric_limits<double>::infinity(), -5.0,-4.5,-4.0,-3.5,-3.0,-2.5,-2.0,-1.5,-1.0,-0.5,0.0,0.5,1.0,1.5,2.0,2.5,3.0,3.5,4.0,4.5,5.0,std::numeric_limits<double>::infinity()};
32 m_vals["rapidity"]=std::vector<double>(m_bins.at("rapidity").size()-1,0.0);
33 m_errs["rapidity"]=std::vector<double>(m_bins.at("rapidity").size()-1,0.0);
34
35}
36
38{
39 double w=evt.weight();
42 for(auto p: evt.particles() )
43 {
44 if (p->status()!=1) continue;
45 double eta=p->momentum().eta();
46 int bin=std::distance(m_bins["rapidity"].begin(), lower_bound(m_bins["rapidity"].begin(),m_bins["rapidity"].end(),eta))-1;
47 if (bin<0) bin=0;
48 m_vals["rapidity"][bin]+=w;
49 m_errs["rapidity"][bin]+=w*w;
50 }
51}
52
54 if (!m_stream) return;
55 auto* ofs = dynamic_cast<std::ofstream*>(m_stream);
56 for (size_t i=1; i<m_vals["rapidity"].size()-1; i++)
57 {
58 double val=m_vals["rapidity"][i]/m_sum_of_weights/(m_bins["rapidity"][i+1]-m_bins["rapidity"][i]);
59 double err=sqrt(m_errs["rapidity"][i])/m_sum_of_weights/(m_bins["rapidity"][i+1]-m_bins["rapidity"][i]);
60 (*ofs)<< std::fixed << std::setprecision( 6 )<<m_bins["rapidity"][i]<<" "<<m_bins["rapidity"][i+1]<<" "<<val<<" "<<err<<std::endl;
61 }
62 if (ofs && !ofs->is_open()) return;
63 if (ofs) ofs->close();
64
65}
66
67} // namespace HepMC3
Definition of class AnalysisExample.
#define HEPMC3_ERROR(MESSAGE)
Macro for printing error messages.
Definition: Errors.h:24
Example analysis. Produces a rapidity distribution of final state particles.
double m_sum_of_weights2
Sum of event weights**2.
AnalysisExample(const std::string &filename, std::shared_ptr< GenRunInfo > run)
Constructor.
void close() override
Close file stream.
std::map< std::string, std::vector< double > > m_errs
Uncertainties.
std::map< std::string, std::vector< double > > m_vals
Values.
std::map< std::string, std::vector< double > > m_bins
Binings.
void write_event(const GenEvent &evt) override
Write event to file.
std::ostream * m_stream
Output stream.
double m_sum_of_weights
Sum of event weights.
Stores event-related information.
Definition: GenEvent.h:41
double weight(const unsigned long &index=0) const
Definition: GenEvent.h:103
const std::vector< ConstGenParticlePtr > & particles() const
Get list of particles (const)
Definition: GenEvent.cc:39
Stores run-related information.
Definition: GenRunInfo.h:33
HepMC3 main namespace.