MCParticleGraph Class Reference

Class to build, validate and sort a particle decay chain. More...

#include <MCParticleGraph.h>

Classes
class	GraphParticle
	Class to represent Particle data in graph. More...
class	ParticleSorter
	Class to go over all the particles in the Graph an sort them in a sensible way. More...

Public Types
enum	GraphOptions {   c_setNothing = 0 ,   c_setDecayVertex = 1 ,   c_setDecayTime = 2 ,   c_setDecayInfo = c_setDecayVertex | c_setDecayTime ,   c_checkCyclic = 4 ,   c_clearParticles = 8 }
	Possible options for generating the MCParticle list. More...
typedef std::pair< unsigned int, unsigned int >	DecayLine
	Type representing a decay in the graph.

Public Member Functions
	BELLE2_DEFINE_EXCEPTION (CyclicReferenceError, "Cyclic decay, cannot continue")
	The exception is thrown if a cyclic reference in the graph was detected.
	BELLE2_DEFINE_EXCEPTION (NotSameGraphError, "Particles not from same graph")
	The exception is thrown if two particles do not belong to the same graph.
	BELLE2_DEFINE_EXCEPTION (NonContinousDaughtersError, "Can not represent decay graph, non continuous indices for daughters")
	The exception is thrown if a non-physical decay was detected in the graph.
	BELLE2_DEFINE_EXCEPTION (DaughterHasMotherError, "A daughter particle was already assigned to a mother. A particle can't have two mothers!")
	The exception is thrown if a daughter already has a mother assigned to it.
	BELLE2_DEFINE_EXCEPTION (OutOfRangeError, "Index out of range")
	The exception is thrown if the specified index is out of range.
	MCParticleGraph ()
	Constructor.
virtual	~MCParticleGraph ()
	Destructor.
GraphParticle &	addParticle ()
	Add new particle to the graph.
void	addDecay (GraphParticle &mother, GraphParticle &daughter)
	Add decay information between two particles.
GraphParticle &	operator[] (size_t i)
	Return reference to added particle with range check.
size_t	size () const
	Return the number of particles in the graph.
void	generateList (const std::string &name="", int options=c_setNothing)
	Generates the MCParticle list and stores it in the StoreArray with the given name.
void	loadList (const std::string &name="")
	Load the MCParticle list given by name into the Graph.
void	clear ()
	Reset particles and decay information to make the class reusable.

Protected Attributes
MemoryPool< GraphParticle >	m_particles
	internal list of particles
std::set< DecayLine >	m_decays
	internal set of decay lines

Detailed Description

Class to build, validate and sort a particle decay chain.

Several particles can be added with addParticle(). Decay information between these particles can be added using addDecay(), MCParticleGraph::Particle::decaysInto() and MCParticleGraph::Particle::comesFrom().

Once all all particles and decays are added and their parameters set, call generateList() to fill the specified StoreArray with the resulting MCParticle list. The decay chain will be checked for cyclic references and a runtime_error will be thrown in that case. The particle will be sorted breadth first: First all primary particles, then all particles first generation and so on.

Definition at line 37 of file MCParticleGraph.h.

Member Typedef Documentation

DecayLine

typedef std::pair<unsigned int, unsigned int> DecayLine

Type representing a decay in the graph.

Definition at line 56 of file MCParticleGraph.h.

Member Enumeration Documentation

GraphOptions

enum GraphOptions

Possible options for generating the MCParticle list.

Enumerator
c_setNothing	Do nothing special.
c_setDecayVertex	Set the decay vertex to the production vertex of the last daughter (ordered by production time)
c_setDecayTime	Set decay time to the largest production time of the daughters.
c_setDecayInfo	Set decay time and vertex.
c_checkCyclic	Check for cyclic dependencies.
c_clearParticles	Clear the particle list before adding the graph.

Definition at line 59 of file MCParticleGraph.h.

                      {
      c_setNothing      = 0, 
      c_setDecayVertex = 1, 
      c_setDecayTime   = 2, 
      c_setDecayInfo   = c_setDecayVertex | c_setDecayTime, 
      c_checkCyclic     = 4,  
      c_clearParticles = 8 
    };

Constructor & Destructor Documentation

MCParticleGraph()

MCParticleGraph ( )

inline

Constructor.

Definition at line 208 of file MCParticleGraph.h.

{}

~MCParticleGraph()

virtual ~MCParticleGraph ( )

inlinevirtual

Destructor.

Frees the allocated spaces

Definition at line 214 of file MCParticleGraph.h.

{ clear(); }

Member Function Documentation

generateList()

void generateList	(	const std::string &	name = "",
		int	options = c_setNothing
	)

Generates the MCParticle list and stores it in the StoreArray with the given name.

The graph will be checked for validity. If a cyclic reference is detected, a runtime_error is thrown. Similar, if the decay chain cannot be represented with continuous daughter indices, a runtime_error is raised. This can happen for artificial kinds of decays (eg: a->b,c,d; b->c,e;) but should not happen in physical cases.

Parameters

name	Name of the StoreArray for the MCParticle list
options	Additional options which steer the creation of the StoreArray.

See also

class MCParticle

Definition at line 208 of file MCParticleGraph.cc.

{
  StoreArray<MCParticle> MCParticles(name);
 
  //Make Graph and connect all primary vertices (particles without mother)
  //to an artificial 0ths vertex to be able to find them easily
  typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS> Graph;
  int num_particles(0);
  //Determine number of not ignored particles and add an edge from 0ths vertex to any primary
  //particle
  for (unsigned int i = 0; i < m_particles.size(); ++i) {
    if (!m_particles[i]->m_ignore) ++num_particles;
    if (m_particles[i]->m_primary) m_decays.insert(DecayLine(0, i + 1));
  }
  Graph g(m_decays.begin(), m_decays.end(), m_particles.size() + 1);
 
  //Check for cyclic dependency
  if (options & c_checkCyclic) {
    cycle_detector vis;
    depth_first_search(g, visitor(vis));
  }
 
  //Fill TClonesArray in correct order
  if (options & c_clearParticles) MCParticles.getPtr()->Clear();
  MCParticles.getPtr()->Expand(num_particles + MCParticles.getEntries());
  MCParticleGraph::ParticleSorter psorter(m_particles, MCParticles.getPtr(), options & c_setDecayVertex, options & c_setDecayTime);
  psorter.setStartIndex(MCParticles.getEntries());
  psorter.sort(g);
}

loadList()

void loadList

(

const std::string &

name = ""

)

Load the MCParticle list given by name into the Graph.

Parameters

name	Name of the StoreArray for the MCParticle list

See also

class MCParticle

Definition at line 238 of file MCParticleGraph.cc.

{
  StoreArray<MCParticle> MCParticles(name);
  if (!MCParticles) {
    B2ERROR("MCParticle Collection is not valid, cannot load into Graph");
    return;
  }
 
  unsigned numParticles = MCParticles.getEntries();
  unsigned particleOffset = size();
  //Here we assume that the MCParticle collection is somehow ordered: All
  //particles which are product of a decay come in the list after the mother,
  //thus having a higher index. This is true for all lists generated by the
  //MCParticleGraph and also for the standard lists produced by Evtgen and
  //similar generators.
  for (unsigned i = 0; i < numParticles; ++i) {
    GraphParticle& newParticle = addParticle();
    const MCParticle& oldParticle = *MCParticles[i];
    //Copy all values
    newParticle = oldParticle;
    //If this particle has a mother we just add the decay to this mother
    const MCParticle* oldMother = oldParticle.getMother();
    if (oldMother != nullptr) {
      unsigned motherIndex  = oldMother->getArrayIndex() + particleOffset;
      if (motherIndex >= size())
        B2FATAL("MCParticle collection \"" << name << "\" not sorted correctly: mother index larger than daughter. Cannot load into Graph");
      newParticle.comesFrom((*this)[oldMother->getArrayIndex() + particleOffset]);
    }
  }
}

operator[]()

GraphParticle & operator[] ( size_t  i )

inline

Return reference to added particle with range check.

Returns

A reference to the particle given by its index.

Definition at line 236 of file MCParticleGraph.h.

{ if (i >= m_particles.size()) throw OutOfRangeError(); return *m_particles[i]; }

size()

size_t size ( ) const

inline

Return the number of particles in the graph.

Returns

The number of particles in the graph.

Definition at line 242 of file MCParticleGraph.h.

{ return m_particles.size(); }

Member Data Documentation

m_decays

std::set<DecayLine> m_decays

protected

internal set of decay lines

Definition at line 283 of file MCParticleGraph.h.

m_particles

MemoryPool<GraphParticle> m_particles

protected

internal list of particles

Definition at line 282 of file MCParticleGraph.h.

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

• mdst/dataobjects/include/MCParticleGraph.h
• mdst/dataobjects/src/MCParticleGraph.cc