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PDEFoamDiscriminantDensity.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: PDEFoamDiscriminantDensity *
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 PDEFoamDiscriminantDensity::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::PDEFoamDiscriminantDensity
35 \ingroup TMVA
36 
37 This is a concrete implementation of PDEFoam. Density(...)
38 estimates the discriminant density at a given phase-space point
39 using range-searching. The discriminant D is defined as
40 
41  D = #events with given class / total number of events
42 */
44 
45 #include "TMVA/BinarySearchTree.h"
47 #include "TMVA/MsgLogger.h"
49 #include "TMVA/Types.h"
50 #include "TMVA/Volume.h"
51 
52 #include "Rtypes.h"
53 
54 #include <cmath>
55 #include <vector>
56 
58 
59 ////////////////////////////////////////////////////////////////////////////////
60 
63  , fClass(0)
64 {}
65 
66 ////////////////////////////////////////////////////////////////////////////////
67 /// User constructor:
68 ///
69 /// Parameters:
70 ///
71 /// - box - size of the range-searching box (n-dimensional
72 /// std::vector)
73 ///
74 /// - cls - event class used for the range-searching
75 
78  , fClass(cls)
79 {
80 }
81 
82 ////////////////////////////////////////////////////////////////////////////////
83 /// Copy constructor
84 
86  : PDEFoamDensityBase(distr)
87  , fClass(distr.fClass)
88 {
89 }
90 
91 ////////////////////////////////////////////////////////////////////////////////
92 /// This function is needed during the foam buildup. It returns the
93 /// average number density of events of type fClass within the
94 /// range-searching volume (specified by fBox).
95 ///
96 /// Parameters:
97 ///
98 /// - xev - event vector (in [fXmin,fXmax]) to place the box at
99 ///
100 /// - event_density - here the event density is stored
101 ///
102 /// Returns:
103 ///
104 /// Number of events (event weights) of type fClass, which were
105 /// found in the range-searching volume at point 'xev', divided by
106 /// the box volume.
107 
108 Double_t TMVA::PDEFoamDiscriminantDensity::Density(std::vector<Double_t> &xev, Double_t &event_density)
109 {
110  if (!fBst)
111  Log() << kFATAL << "<PDEFoamDiscriminantDensity::Density()> Binary tree not set!" << Endl;
112 
113  //create volume around point to be found
114  std::vector<Double_t> lb(GetBox().size());
115  std::vector<Double_t> ub(GetBox().size());
116 
117  // probe volume relative to hypercube with edge length 1:
118  const Double_t probevolume_inv = 1.0 / GetBoxVolume();
119 
120  // set upper and lower bound for search volume
121  for (UInt_t idim = 0; idim < GetBox().size(); ++idim) {
122  lb[idim] = xev[idim] - GetBox().at(idim) / 2.0;
123  ub[idim] = xev[idim] + GetBox().at(idim) / 2.0;
124  }
125 
126  TMVA::Volume volume(&lb, &ub); // volume to search in
127  std::vector<const TMVA::BinarySearchTreeNode*> nodes; // BST nodes found
128 
129  // do range searching
130  const Double_t sumOfWeights = fBst->SearchVolume(&volume, &nodes);
131 
132  // store density based on total number of events
133  event_density = nodes.size() * probevolume_inv;
134 
135  Double_t n_sig = 0; // number of signal events found
136  // calc number of signal events in nodes
137  for (std::vector<const TMVA::BinarySearchTreeNode*>::const_iterator it = nodes.begin();
138  it != nodes.end(); ++it) {
139  if ((*it)->GetClass() == fClass) // signal node
140  n_sig += (*it)->GetWeight();
141  }
142 
143  // return: (n_sig/n_total) / (cell_volume)
144  return (n_sig / (sumOfWeights + 0.1)) * probevolume_inv;
145 }
BinarySearchTreeNode.h
TMVA::PDEFoamDiscriminantDensity
Definition: PDEFoamDiscriminantDensity.h:68
TMVA::PDEFoamDensityBase
Definition: PDEFoamDensityBase.h:72
ClassImp
#define ClassImp(name)
Definition: Rtypes.h:364
TMVA::Volume
Definition: Volume.h:69
TMath::Log
Double_t Log(Double_t x)
Definition: TMath.h:749
PDEFoamDensityBase.h
box
void box(Int_t pat, Double_t x1, Double_t y1, Double_t x2, Double_t y2)
Definition: fillpatterns.C:1
TMVA::PDEFoamDiscriminantDensity::PDEFoamDiscriminantDensity
PDEFoamDiscriminantDensity()
Definition: PDEFoamDiscriminantDensity.cxx:61
TMVA::PDEFoamDiscriminantDensity::Density
virtual Double_t Density(std::vector< Double_t > &Xarg, Double_t &event_density)
This function is needed during the foam buildup.
Definition: PDEFoamDiscriminantDensity.cxx:108
Volume.h
PDEFoamDiscriminantDensity.h
MsgLogger.h
BinarySearchTree.h
Types.h
fClass
Cppyy::TCppType_t fClass
Definition: DeclareConverters.h:259
TMVA::Endl
MsgLogger & Endl(MsgLogger &ml)
Definition: MsgLogger.h:182
unsigned int
Double_t
double Double_t
Definition: RtypesCore.h:59
Rtypes.h