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Reference Guide
PDEFoamTargetDensity.cxx
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1 // @(#)root/tmva $Id$
2 // Author: Tancredi Carli, Dominik Dannheim, Alexander Voigt
3 
4 /**********************************************************************************
5  * Project: TMVA - a Root-integrated toolkit for multivariate data analysis *
6  * Package: TMVA *
7  * Classes: PDEFoamTargetDensity *
8  * Web : http://tmva.sourceforge.net *
9  * *
10  * Description: *
11  * The TFDSITR class provides an interface between the Binary search tree *
12  * and the PDEFoam object. In order to build-up the foam one needs to *
13  * calculate the density of events at a given point (sampling during *
14  * Foam build-up). The function PDEFoamTargetDensity::Density() does this job. It *
15  * uses a binary search tree, filled with training events, in order to *
16  * provide this density. *
17  * *
18  * Authors (alphabetical): *
19  * Tancredi Carli - CERN, Switzerland *
20  * Dominik Dannheim - CERN, Switzerland *
21  * S. Jadach - Institute of Nuclear Physics, Cracow, Poland *
22  * Alexander Voigt - TU Dresden, Germany *
23  * Peter Speckmayer - CERN, Switzerland *
24  * *
25  * Copyright (c) 2008, 2010: *
26  * CERN, Switzerland *
27  * MPI-K Heidelberg, Germany *
28  * *
29  * Redistribution and use in source and binary forms, with or without *
30  * modification, are permitted according to the terms listed in LICENSE *
31  * (http://tmva.sourceforge.net/LICENSE) *
32  **********************************************************************************/
33 
34 /*! \class TMVA::PDEFoamTargetDensity
35 \ingroup TMVA
36 This is a concrete implementation of PDEFoam. Density(...)
37 estimates the target density (target number: fTarget) at a given
38 phase-space point using range-searching.
39 */
40 
42 
43 #include "TMVA/BinarySearchTree.h"
44 #include "TMVA/MsgLogger.h"
46 #include "TMVA/Types.h"
47 #include "TMVA/Volume.h"
48 
49 #include "Rtypes.h"
50 
51 #include <cmath>
52 #include <vector>
53 
55 
56 ////////////////////////////////////////////////////////////////////////////////
57 
60  , fTarget(0)
61 {}
62 
63 ////////////////////////////////////////////////////////////////////////////////
64 /// User constructor
65 ///
66 /// Parameters:
67 ///
68 /// - box - size of the range-searching box (n-dimensional
69 /// std::vector)
70 ///
71 /// - target - the target number to calculate the density for
72 
75  , fTarget(target)
76 {
77 }
78 
79 ////////////////////////////////////////////////////////////////////////////////
80 /// Copy constructor
81 
83  : PDEFoamDensityBase(distr)
84  , fTarget(distr.fTarget)
85 {
86 }
87 
88 ////////////////////////////////////////////////////////////////////////////////
89 /// This function is needed during the foam buildup. It returns the
90 /// average target value within the range-searching box at point
91 /// xev, divided by volume (specified by fBox).
92 ///
93 /// Parameters:
94 ///
95 /// - xev - event vector (in [fXmin,fXmax]) to place the box at
96 ///
97 /// - event_density - here the event density is stored
98 ///
99 /// Returns:
100 ///
101 /// Average target value in the range-searching volume at point
102 /// 'xev', divided by the box volume.
103 
104 Double_t TMVA::PDEFoamTargetDensity::Density(std::vector<Double_t> &xev, Double_t &event_density)
105 {
106  if (!fBst)
107  Log() << kFATAL << "<PDEFoamTargetDensity::Density()> Binary tree not found!" << Endl;
108 
109  //create volume around point to be found
110  std::vector<Double_t> lb(GetBox().size());
111  std::vector<Double_t> ub(GetBox().size());
112 
113  // probevolume relative to hypercube with edge length 1:
114  const Double_t probevolume_inv = 1.0 / GetBoxVolume();
115 
116  // set upper and lower bound for search volume
117  for (UInt_t idim = 0; idim < GetBox().size(); ++idim) {
118  lb[idim] = xev[idim] - GetBox().at(idim) / 2.0;
119  ub[idim] = xev[idim] + GetBox().at(idim) / 2.0;
120  }
121 
122  TMVA::Volume volume(&lb, &ub); // volume to search in
123  std::vector<const TMVA::BinarySearchTreeNode*> nodes; // BST nodes found
124 
125  // do range searching
126  const Double_t sumOfWeights = fBst->SearchVolume(&volume, &nodes);
127 
128  // store density based on total number of events
129  event_density = nodes.size() * probevolume_inv;
130 
131  Double_t n_tar = 0; // number of target events found
132  // now sum over all nodes->GetTarget(0);
133  for (std::vector<const TMVA::BinarySearchTreeNode*>::const_iterator it = nodes.begin();
134  it != nodes.end(); ++it) {
135  n_tar += ((*it)->GetTargets()).at(fTarget) * ((*it)->GetWeight());
136  }
137 
138  // return: (n_tar/n_total) / (cell_volume)
139  return (n_tar / (sumOfWeights + 0.1)) * probevolume_inv;
140 }
TMVA::PDEFoamDensityBase
This is an abstract class, which provides an interface for a PDEFoam density estimator.
Definition: PDEFoamDensityBase.h:47
ClassImp
#define ClassImp(name)
Definition: Rtypes.h:364
TMVA::Volume
Volume for BinarySearchTree.
Definition: Volume.h:47
TMath::Log
Double_t Log(Double_t x)
Definition: TMath.h:760
PDEFoamDensityBase.h
box
void box(Int_t pat, Double_t x1, Double_t y1, Double_t x2, Double_t y2)
Definition: fillpatterns.C:1
Volume.h
MsgLogger.h
BinarySearchTree.h
TMVA::PDEFoamTargetDensity::PDEFoamTargetDensity
PDEFoamTargetDensity()
Definition: PDEFoamTargetDensity.cxx:58
TMVA::PDEFoamTargetDensity::Density
virtual Double_t Density(std::vector< Double_t > &Xarg, Double_t &event_density)
This function is needed during the foam buildup.
Definition: PDEFoamTargetDensity.cxx:104
Types.h
TMVA::Endl
MsgLogger & Endl(MsgLogger &ml)
Definition: MsgLogger.h:158
unsigned int
TMVA::PDEFoamTargetDensity
This is a concrete implementation of PDEFoam.
Definition: PDEFoamTargetDensity.h:44
Double_t
double Double_t
Definition: RtypesCore.h:59
PDEFoamTargetDensity.h
Rtypes.h