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JMARKOV::JMarkovEnsembleIntegrator Class Referenceabstract

Abstract base class for implementations of the JMarkovIntegrator interface, where the sample distribution is based on histograms filled from an ensemble of representative paths. More...

#include <JMarkovIntegrator.hh>

Inheritance diagram for JMARKOV::JMarkovEnsembleIntegrator:
JMARKOV::JMarkovIntegrator JMARKOV::JMarkovEnsembleIntegrator1D JMARKOV::JMarkovEnsembleIntegrator3D

Public Member Functions

 JMarkovEnsembleIntegrator (const vector< JPhotonPath > &_ensemble, JTargetModel *_trg, int _nbinsx, int _nbinsy, int _nbinsz)
 
virtual ~JMarkovEnsembleIntegrator ()
 
virtual void writeHistograms ()=0
 write the histograms filled from the ensemble More...
 
vector< double > integrate (int N, int nscat, JSourceModel *src, JScatteringModel *sm, JTargetModel *trg, double lambda_abs)
 Integrate with N samples. More...
 
vector< double > dummy_integrate (int N, int nscat, JSourceModel *src, JScatteringModel *sm, JTargetModel *trg, double lambda_abs)
 Integrate a test function with N samples. More...
 
vector< JPhotonPathget_diagnostic_ensemble (int N, int nscat, JSourceModel *src, JScatteringModel *sm, JTargetModel *trg, double lambda_abs)
 Return photon paths generated with the generatePath method. More...
 

Protected Member Functions

JPosition3D generatePosition (int nscat, int nv, double &winv)
 generate a position for vertex nv for the given number of scatterings, winv will be set to 1/weight More...
 
virtual JPosition3D generateScatteringVertexPosition (int nscat, int nv, double &winv)=0
 
int getIndex (int nv, int nscat)
 return the internal index for a given number of scatterings and vertex number More...
 
void initgenerators (int nscat)
 initialize the position generators for a given number of scatterings (i.e. create histograms and fill them from the ensemble) More...
 
void init_target_generator (int nscat)
 initialize the generator for a target vertex for a given number of scatterings More...
 
virtual void init_scattering_vertex_generators (int nscat)=0
 
void free_target_gens ()
 
virtual JPhotonPath generatePath (int nscat, double &winv)
 Generate a random photon path with a given number of scatterings. More...
 

Protected Attributes

vector< JSphereGenerator * > target_gens
 
vector< JPhotonPathensemble
 
int nbinsx
 
int nbinsy
 
int nbinsz
 
JTargetModeltrg
 
JPosition3D source_position
 

Detailed Description

Abstract base class for implementations of the JMarkovIntegrator interface, where the sample distribution is based on histograms filled from an ensemble of representative paths.

Definition at line 198 of file JMarkovIntegrator.hh.

Constructor & Destructor Documentation

JMARKOV::JMarkovEnsembleIntegrator::JMarkovEnsembleIntegrator ( const vector< JPhotonPath > &  _ensemble,
JTargetModel _trg,
int  _nbinsx,
int  _nbinsy,
int  _nbinsz 
)
inline

Definition at line 202 of file JMarkovIntegrator.hh.

202  : ensemble(_ensemble), nbinsx(_nbinsx), nbinsy(_nbinsy), nbinsz(_nbinsz), trg(_trg) {
203  // check that the ensemble size is at least one photon path
204  if( ensemble.size()==0 ) {
205  cerr << "FATAL ERROR in JMarkov3DensembleIntegrator constructor. Ensemble size = 0." << endl ;
206  exit(1) ;
207  }
208 
209  // check that the position of the first vertex is the same throughout the ensemble
210  for( vector<JPhotonPath>::iterator it=ensemble.begin(); it!=ensemble.end(); ++it ) {
211  if( (*it)[0].getDistance(ensemble.front()[0]) > 0 ) {
212  cerr << "Fatal error in JMarkovEnsembleIntegrator, first vertex positions are not all the same." << endl ;
213  exit(1) ;
214  }
215  }
216  // set source position based on ensemble
217  source_position = ensemble.front()[0] ;
218  }
exit
Definition: JPizza.sh:36
virtual JMARKOV::JMarkovEnsembleIntegrator::~JMarkovEnsembleIntegrator ( )
inlinevirtual

Definition at line 220 of file JMarkovIntegrator.hh.

220 {} ;

Member Function Documentation

virtual void JMARKOV::JMarkovEnsembleIntegrator::writeHistograms ( )
pure virtual

write the histograms filled from the ensemble

Implemented in JMARKOV::JMarkovEnsembleIntegrator3D, and JMARKOV::JMarkovEnsembleIntegrator1D.

JPosition3D JMARKOV::JMarkovEnsembleIntegrator::generatePosition ( int  nscat,
int  nv,
double &  winv 
)
inlineprotectedvirtual

generate a position for vertex nv for the given number of scatterings, winv will be set to 1/weight

Implements JMARKOV::JMarkovIntegrator.

Definition at line 228 of file JMarkovIntegrator.hh.

228  {
229  // source vertex
230  if( nv==0 ) {
231  winv = 1.0 ;
232  return source_position ;
233  }
234  // target vertex
235  if( nv == nscat+1 ) {
236  if( nscat+1>(int)target_gens.size() || target_gens[nscat] == NULL ) {
237  initgenerators(nscat) ;
238  }
239  JPosition3D pos = target_gens[nscat]->getPosition() ;
240  winv = 1.0/target_gens[nscat]->getWeight(pos) ;
241  return pos ;
242  } else {
243  // scattering vertex
244  return generateScatteringVertexPosition(nscat,nv,winv) ;
245  }
246  }
virtual JPosition3D generateScatteringVertexPosition(int nscat, int nv, double &winv)=0
void initgenerators(int nscat)
initialize the position generators for a given number of scatterings (i.e. create histograms and fill...
vector< JSphereGenerator * > target_gens
virtual JPosition3D JMARKOV::JMarkovEnsembleIntegrator::generateScatteringVertexPosition ( int  nscat,
int  nv,
double &  winv 
)
protectedpure virtual
int JMARKOV::JMarkovEnsembleIntegrator::getIndex ( int  nv,
int  nscat 
)
inlineprotected

return the internal index for a given number of scatterings and vertex number

Definition at line 251 of file JMarkovIntegrator.hh.

251  {
252  // indices are distributed as follows
253  // [0]: nscat=1, nv=1
254  // [1]: nscat=2, nv=1
255  // [2]: nscat=2, nv=2
256  // [3]: nscat=3, nv=1
257  // [4]: nscat=3, nv=2
258  // etc.
259  return (nscat*(nscat-1))/2 + nv - 1 ;
260  }
void JMARKOV::JMarkovEnsembleIntegrator::initgenerators ( int  nscat)
inlineprotected

initialize the position generators for a given number of scatterings (i.e. create histograms and fill them from the ensemble)

Definition at line 263 of file JMarkovIntegrator.hh.

263  {
264  // target vertex
265  init_target_generator(nscat) ;
266 
267  // scattering vertices
269  }
virtual void init_scattering_vertex_generators(int nscat)=0
void init_target_generator(int nscat)
initialize the generator for a target vertex for a given number of scatterings
void JMARKOV::JMarkovEnsembleIntegrator::init_target_generator ( int  nscat)
inlineprotected

initialize the generator for a target vertex for a given number of scatterings

Definition at line 272 of file JMarkovIntegrator.hh.

272  {
273  if( (int)target_gens.size() <= nscat ) target_gens.resize( nscat+1 ) ;
274 
275  if( trg->getRadius()>0 ) {
276  // for a finite target, we fill a "sphere generator" from the ensemble
277  char hname[200] ;
278  sprintf( hname, "htarget_nscat%i", nscat ) ;
279  TH2D* ht = new TH2D(hname,";cos(#theta);#phi",100,-1,1,100,-M_PI,M_PI) ;
280  for( vector<JPhotonPath>::iterator it=ensemble.begin() ; it!=ensemble.end() ; ++it ) {
281  if( it->n-2 != nscat ) continue ;
282  JVersor3D dir( it->back() - trg->getPosition() ) ;
283  ht->Fill( dir.getDZ(), dir.getPhi() ) ;
284  }
285  target_gens[nscat] = new JSphereGenerator( trg->getPosition(), trg->getRadius(), ht ) ;
286  delete ht ;
287  } else {
288  // for an infinitesimal target, we create a "generator" that only generates the single point
289  target_gens[nscat] = new JSphereGenerator( trg->getPosition() ) ;
290  }
291  }
double getRadius() const
vector< JSphereGenerator * > target_gens
skip continue
Definition: JTuneHV.sh:89
const JPosition3D & getPosition() const
Implementation of the JGenerator interface.
virtual void JMARKOV::JMarkovEnsembleIntegrator::init_scattering_vertex_generators ( int  nscat)
protectedpure virtual
void JMARKOV::JMarkovEnsembleIntegrator::free_target_gens ( )
inlineprotected

Definition at line 295 of file JMarkovIntegrator.hh.

295  {
296  for( vector<JSphereGenerator*>::iterator it=target_gens.begin() ; it!=target_gens.end() ; ++it ) {
297  if( *it != NULL ) delete *it ;
298  }
299  }
vector< JSphereGenerator * > target_gens
vector< double > JMARKOV::JMarkovIntegrator::integrate ( int  N,
int  nscat,
JSourceModel src,
JScatteringModel sm,
JTargetModel trg,
double  lambda_abs 
)
inherited

Integrate with N samples.

Returns a vector with the contribution to the integral of each sample. The mean of those values is the estimate of the result of the integral, while the distribution itself can be used to estimate the stability of the result. In this distribution, you want to avoid

  • long tails (because they make the result unstable)
  • small contributions (because it means that parts of the parameter space are being oversampled, so it is less efficient) This can be achieved by tuning the sample distribution to the problem at hand.

Definition at line 130 of file JMarkovIntegrator.hh.

130  {
131  vector<double> contributions(N,-1) ;
132 
133  for( int i=0 ; i<N ; ++i ) {
134  double winv ;
135  JPhotonPath p = generatePath(nscat,winv) ;
136 
137  double rho = getPhotonPathProbabilityDensity(p,src,sm,trg,lambda_abs) ;
138  contributions[i] = rho * winv ;
139  }
140  return contributions ;
141  }
A photon path.
Definition: JPhotonPath.hh:38
then usage $script< input file >[option[primary[working directory]]] nWhere option can be N
Definition: JMuonPostfit.sh:40
virtual JPhotonPath generatePath(int nscat, double &winv)
Generate a random photon path with a given number of scatterings.
double getPhotonPathProbabilityDensity(JPhotonPath &p, JSourceModel *src, JScatteringModel *sm, JTargetModel *trg, double lambda_abs)
Return the probability density for a photon path with the given ingredients.
vector< double > JMARKOV::JMarkovIntegrator::dummy_integrate ( int  N,
int  nscat,
JSourceModel src,
JScatteringModel sm,
JTargetModel trg,
double  lambda_abs 
)
inherited

Integrate a test function with N samples.

This can be used as a sanity check for derived classes of JMarkovIntegrator.

The integral should yield 1 when the complete relevant part of the volume is taken into account. If it does not, it may be a sign that the implementation is not correct.

Returns a vector with the contribution to the integral of each sample.

Definition at line 143 of file JMarkovIntegrator.hh.

143  {
144  vector<double> contributions(N,-1) ;
145 
146  for( int i=0 ; i<N ; ++i ) {
147  const double r = 10 ;
148  double winv ;
149  JPhotonPath p = generatePath(nscat,winv) ;
150  double rho = 1.0/(4.0/3.0*M_PI*r*r*r) ;
151  if( p[1].getLength()>r ) rho = 0 ;
152  contributions[i] = rho * winv ;
153  }
154  return contributions ;
155  }
A photon path.
Definition: JPhotonPath.hh:38
data_type r[M+1]
Definition: JPolint.hh:868
then usage $script< input file >[option[primary[working directory]]] nWhere option can be N
Definition: JMuonPostfit.sh:40
virtual JPhotonPath generatePath(int nscat, double &winv)
Generate a random photon path with a given number of scatterings.
vector< JPhotonPath > JMARKOV::JMarkovIntegrator::get_diagnostic_ensemble ( int  N,
int  nscat,
JSourceModel src,
JScatteringModel sm,
JTargetModel trg,
double  lambda_abs 
)
inherited

Return photon paths generated with the generatePath method.

This can be used to identify the parts of parameter space that are over- or undersampled in a given problem so that the integrator may be optimized to handle those better.

Definition at line 157 of file JMarkovIntegrator.hh.

157  {
158  vector<JPhotonPath> paths ;
159 
160  for( int i=0 ; i<N ; ++i ) {
161  double winv ;
162  JPhotonPath p = generatePath(nscat,winv) ;
163  paths.push_back(p) ;
164  }
165  return paths ;
166  }
A photon path.
Definition: JPhotonPath.hh:38
then usage $script< input file >[option[primary[working directory]]] nWhere option can be N
Definition: JMuonPostfit.sh:40
virtual JPhotonPath generatePath(int nscat, double &winv)
Generate a random photon path with a given number of scatterings.
virtual JPhotonPath JMARKOV::JMarkovIntegrator::generatePath ( int  nscat,
double &  winv 
)
inlineprotectedvirtualinherited

Generate a random photon path with a given number of scatterings.

winv must be set to the inverted probability density to generate this particular path.

Definition at line 94 of file JMarkovIntegrator.hh.

94  {
95  // this default implementation assumes that the vertex positions
96  // are completely uncorrelated
97  JPhotonPath p(nscat) ;
98  double _winv = 1 ;
99  for( int nv=0 ; nv<nscat+2 ; ++nv ) {
100  double part_winv ;
101  p[nv] = generatePosition( nscat, nv, part_winv ) ;
102  _winv *= part_winv ;
103  }
104  winv = _winv ;
105  return p ;
106  }
A photon path.
Definition: JPhotonPath.hh:38
virtual JPosition3D generatePosition(int nscat, int nv, double &winv)=0
Generate a random position for vertex nv.

Member Data Documentation

vector<JSphereGenerator*> JMARKOV::JMarkovEnsembleIntegrator::target_gens
protected

Definition at line 301 of file JMarkovIntegrator.hh.

vector<JPhotonPath> JMARKOV::JMarkovEnsembleIntegrator::ensemble
protected

Definition at line 302 of file JMarkovIntegrator.hh.

int JMARKOV::JMarkovEnsembleIntegrator::nbinsx
protected

Definition at line 303 of file JMarkovIntegrator.hh.

int JMARKOV::JMarkovEnsembleIntegrator::nbinsy
protected

Definition at line 304 of file JMarkovIntegrator.hh.

int JMARKOV::JMarkovEnsembleIntegrator::nbinsz
protected

Definition at line 305 of file JMarkovIntegrator.hh.

JTargetModel* JMARKOV::JMarkovEnsembleIntegrator::trg
protected

Definition at line 306 of file JMarkovIntegrator.hh.

JPosition3D JMARKOV::JMarkovEnsembleIntegrator::source_position
protected

Definition at line 307 of file JMarkovIntegrator.hh.


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