HepevtReader Class Reference

Class to read Hepevt files and store the content in a MCParticle graph. More...

#include <HepevtReader.h>

Public Member Functions
	BELLE2_DEFINE_EXCEPTION (HepEvtCouldNotOpenFileError, "Could not open file %1% !")
	Exception is thrown if the HepEvt file could not be opened.
	BELLE2_DEFINE_EXCEPTION (HepEvtInvalidDaughterIndicesError, "Line %1%: Invalid daughter indices d1=%2%, d2=%3%, N=%4% (0<=d1<=d2<=N required)")
	Exception is thrown if the given indices of the daughters are not valid.
	BELLE2_DEFINE_EXCEPTION (HepEvtHeaderNotValidError, "Line %1%: Event header not understood: %2%")
	Exception is thrown if the header specifying the event header could not be parsed.
	BELLE2_DEFINE_EXCEPTION (HepEvtConvertFieldError, "Line %1%: Could not convert field %2%: %3%")
	Exception is thrown if a field in the HepEvt file could not be converted to a number.
	BELLE2_DEFINE_EXCEPTION (HepEvtParticleFormatError, "Line %1%: Particle format not understood, got %2% fields !")
	Exception is thrown if the format of a line of the HepEvt file could not be parsed.
	BELLE2_DEFINE_EXCEPTION (HepEvtEmptyEventError, "Line %1%: Number of particles in event is %2% ! (This could mean EOF is reached.) ")
	Exception is thrown if the number of particles for this event is 0 or less.
	HepevtReader ()
	Constructor.
	~HepevtReader ()
	Destructor.
void	open (const std::string &filename)
	Opens an ascii file and prepares it for reading.
void	closeCurrentInputFile ()
	Closes the current input file to allow opening the next one.
int	getEvent (MCParticleGraph &graph, double &weight)
	Reads the next event and stores the result in the given MCParticle graph.
bool	skipEvents (int n)
	Skips a given number of events.

Public Attributes
int	m_nVirtual
	The number of particles in each event with a set Virtual flag.
bool	m_wrongSignPz
	Bool to indicate that HER and LER were swapped.

Protected Types
typedef boost::tokenizer< boost::char_separator< char > >	tokenizer
	Just a typedef for simple use of the boost::tokenizer to split the lines.

Protected Member Functions
std::string	getLine ()
	Returns the current line from the Hepevt ascii file.
int	readEventHeader (int &eventID, double &eventWeight)
	Reads the event header from the hepevt file.
void	readParticle (MCParticleGraph::GraphParticle &particle)
	Reads the information for a single particle from the Hepevt file.

Protected Attributes
int	m_lineNr
	The current line number within the ascii file.
std::ifstream	m_input
	The input stream of the ascii file.

Static Protected Attributes
static const boost::char_separator< char >	sep
	The characters at which to split, defaults to ",; \t".

Detailed Description

Class to read Hepevt files and store the content in a MCParticle graph.

The reader supports retrieving the Hepevt information from an ascii text file. Both formats, the short and the long LUND 7 format are supported.

The events are read sequentially with the option of skipping a certain number of events. Random access of events is not possible.

Definition at line 33 of file HepevtReader.h.

Member Typedef Documentation

tokenizer

typedef boost::tokenizer<boost::char_separator<char> > tokenizer

protected

Just a typedef for simple use of the boost::tokenizer to split the lines.

Definition at line 93 of file HepevtReader.h.

Constructor & Destructor Documentation

HepevtReader()

HepevtReader ( )

inline

Constructor.

Definition at line 55 of file HepevtReader.h.

: m_nVirtual(0), m_wrongSignPz(false), m_lineNr(0) {}

~HepevtReader()

~HepevtReader ( )

inline

Destructor.

Definition at line 60 of file HepevtReader.h.

{ if (m_input) m_input.close(); }

Member Function Documentation

BELLE2_DEFINE_EXCEPTION()

BELLE2_DEFINE_EXCEPTION	(	HepEvtEmptyEventError	,
		"Line %1%: Number of particles in event is %2% ! (This could mean EOF is reached.) "
	)

Exception is thrown if the number of particles for this event is 0 or less.

closeCurrentInputFile()

void closeCurrentInputFile ( )

inline

Closes the current input file to allow opening the next one.

Definition at line 71 of file HepevtReader.h.

{m_input.close();}

getEvent()

int getEvent	(	MCParticleGraph &	graph,
		double &	weight
	)

Reads the next event and stores the result in the given MCParticle graph.

Parameters

graph	Reference to the graph which should be filled with the information from the Hepevt file.
weight	Reference to the event weight which can be filled from the file.

Returns

event number if the event could be read and the number was provided in the file.

Definition at line 34 of file HepevtReader.cc.

{
  int eventID = -1;
  int nparticles = readEventHeader(eventID, eventWeight);
  if (nparticles <= 0) {
    throw (HepEvtEmptyEventError() << m_lineNr << nparticles);
  }
 
  int first = graph.size();
  //Make list of particles
  for (int i = 0; i < nparticles; i++) {
    graph.addParticle();
  }
  //Read particles from file
  for (int i = 0; i < nparticles; ++i) {
    MCParticleGraph::GraphParticle& p = graph[first + i];
    readParticle(p);
 
    if (m_wrongSignPz) { // this means we have to mirror Pz
      ROOT::Math::PxPyPzEVector p4 = p.get4Vector();
      p4.SetPz(-1.0 * p4.Pz());
      p.set4Vector(p4);
    }
 
    //Check for sensible daughter indices
    int d1 = p.getFirstDaughter();
    int d2 = p.getLastDaughter();
    if (d1 < 0 || d1 > nparticles || d2 < d1 || d2 > nparticles) {
      throw (HepEvtInvalidDaughterIndicesError() << m_lineNr << d1 << d2 << nparticles);
    }
    if (d1 == 0) p.addStatus(MCParticle::c_StableInGenerator);
    //Add decays
    for (int index = d1; index <= d2; ++index) {
      if (index > 0) p.decaysInto(graph[first + index - 1]);
    }
 
    //check if particle should be made virtual according to steering options:
    if (i < m_nVirtual)
      p.setVirtual();
  }
  return eventID;
}

getLine()

std::string getLine ( )

protected

Returns the current line from the Hepevt ascii file.

• double eventWeight; /‍**< The event weight if provided in HepEvtfile else 1. *‍/ *‍/

  Returns

  The current line as a string.

Definition at line 95 of file HepevtReader.cc.

{
  std::string line;
  do {
    getline(m_input, line);
    m_lineNr++;
    size_t commentPos = line.find_first_of('#');
    if (commentPos != string::npos) {
      line = line.substr(0, commentPos);
    }
    boost::trim(line);
  } while (line == "" && !m_input.eof());
  return line;
}

open()

void open

(

const std::string &

filename

)

Opens an ascii file and prepares it for reading.

Parameters

filename

The filename of the Hepevt ascii file which should be read.

Definition at line 26 of file HepevtReader.cc.

{
  m_lineNr = 0;
  m_input.open(filename.c_str());
  if (!m_input) throw(HepEvtCouldNotOpenFileError() << filename);
}

readEventHeader()

int readEventHeader ( int &  eventID, double &  eventWeight  )

protected

Reads the event header from the hepevt file.

Parameters

eventID	reference to the eventID which can be read from the file
eventWeight	reference to the eventWeight which can be read from the file

Returns

The number of particles for the current event.

Definition at line 111 of file HepevtReader.cc.

{
  //Get number of particles from file
  int nparticles = -1;
  string line = getLine();
  if (line == "" || m_input.eof()) return -1;
 
  vector<double> fields;
  fields.reserve(15);
 
  tokenizer tokens(line, sep);
  int index(0);
 
  for (const string& tok : tokens) {
    ++index;
    try {
      fields.push_back(boost::lexical_cast<double>(tok));
    } catch (boost::bad_lexical_cast& e) {
      throw (HepEvtConvertFieldError() << m_lineNr << index << tok);
    }
  }
 
  switch (fields.size()) {
    case 1:
      nparticles = static_cast<int>(fields[0]);
      break;
    case 2:
      nparticles = static_cast<int>(fields[1]);
      eventID = static_cast<int>(fields[0]);
      break;
    case 3:
      nparticles = static_cast<int>(fields[1]);
      eventID = static_cast<int>(fields[0]);
      eventWeight = fields[2];
      break;
    default:
      nparticles = static_cast<int>(fields[0]);
      break;
  }
  return nparticles;
}

readParticle()

void readParticle ( MCParticleGraph::GraphParticle &  particle )

protected

Reads the information for a single particle from the Hepevt file.

Parameters

particle

Reference to the particle which will be filled with the information from the Hepevt file.

Definition at line 154 of file HepevtReader.cc.

{
  string line = getLine();
  vector<double> fields;
  fields.reserve(15);
 
  tokenizer tokens(line, sep);
  int index(0);
 
  for (const string& tok : tokens) {
    ++index;
    try {
      fields.push_back(boost::lexical_cast<double>(tok));
    } catch (boost::bad_lexical_cast& e) {
      throw (HepEvtConvertFieldError() << m_lineNr << index << tok);
    }
  }
 
  switch (fields.size()) {
    case 8:
      particle.setStatus(MCParticle::c_PrimaryParticle);
      particle.setPDG(static_cast<int>(fields[1]));
      particle.setFirstDaughter(static_cast<int>(fields[2]));
      particle.setLastDaughter(static_cast<int>(fields[3]));
      particle.setMomentum(ROOT::Math::XYZVector(fields[4], fields[5], fields[6]));
      particle.setMass(fields[7]);
      break;
    case 6:
      particle.setStatus(MCParticle::c_PrimaryParticle);
      particle.setPDG(static_cast<int>(fields[5]));
      particle.setFirstDaughter(0);
      particle.setLastDaughter(0);
      particle.setMomentum(ROOT::Math::XYZVector(fields[0], fields[1], fields[2]));
      particle.setMass(fields[4]);
      particle.setEnergy(fields[3]);
      break;
    //modified Pit
    case 9:
      particle.setStatus(MCParticle::c_PrimaryParticle);
      particle.setPDG(static_cast<int>(fields[8]));
      particle.setFirstDaughter(0);
      particle.setLastDaughter(0);
      particle.setProductionVertex(ROOT::Math::XYZVector(fields[0], fields[1], fields[2])*Unit::mm);
      particle.setMomentum(ROOT::Math::XYZVector(fields[3], fields[4], fields[5]));
      particle.setMass(fields[6]);
      particle.setEnergy(fields[7]);
      break;
    //end modified Pit
    case 15:
      particle.setStatus(MCParticle::c_PrimaryParticle);
      particle.setPDG(static_cast<int>(fields[1]));
      particle.setFirstDaughter(static_cast<int>(fields[4]));
      particle.setLastDaughter(static_cast<int>(fields[5]));
      particle.setMomentum(ROOT::Math::XYZVector(fields[6], fields[7], fields[8]));
      //particle.setEnergy(fields[9]);
      particle.setMass(fields[10]);
      particle.setProductionVertex(ROOT::Math::XYZVector(fields[11], fields[12], fields[13])*Unit::mm);
      particle.setProductionTime(fields[14]*Unit::mm / Const::speedOfLight);
      particle.setValidVertex(true);
      {
        //Warn if energy in Hepevt file differs from calculated energy by more than 0.1%
        const double& E  = particle.getEnergy();
        double dE = fabs(fields[9] - E) / E;
        if (dE > 1e-3) {
          B2WARNING(boost::format("line %d: Energy of particle does not match with expected energy: %.6e != %.6e")
                    % m_lineNr % fields[9] % E);
          B2WARNING(boost::format("delta E = %.2f%% -> ignoring given value") % (dE * 100));
        }
      }
      break;
    default:
      throw (HepEvtParticleFormatError() << m_lineNr << fields.size());
  }
}

skipEvents()

bool skipEvents

(

int

n

)

Skips a given number of events.

Parameters

n	The number of events which should be skipped.

Returns

True if the events could be skipped.

Definition at line 78 of file HepevtReader.cc.

{
  int eventID;
  double weight;
  for (int i = 0; i < n; i++) {
    int nparticles = readEventHeader(eventID, weight);
    if (nparticles < 0) return false;
    for (int j = 0; j < nparticles; j++) getLine();
  }
  return true;
}

Member Data Documentation

m_input

std::ifstream m_input

protected

The input stream of the ascii file.

Definition at line 98 of file HepevtReader.h.

m_lineNr

int m_lineNr

protected

The current line number within the ascii file.

Definition at line 97 of file HepevtReader.h.

m_nVirtual

int m_nVirtual

The number of particles in each event with a set Virtual flag.

Definition at line 88 of file HepevtReader.h.

m_wrongSignPz

bool m_wrongSignPz

Bool to indicate that HER and LER were swapped.

Definition at line 89 of file HepevtReader.h.

sep

const boost::char_separator< char > sep

staticprotected

The characters at which to split, defaults to ",; \t".

Definition at line 95 of file HepevtReader.h.

---

The documentation for this class was generated from the following files:

• generators/hepevt/include/HepevtReader.h
• generators/hepevt/src/HepevtReader.cc