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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 * *
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 * (see tmva/doc/LICENSE) *
32 **********************************************************************************/
33
34/*! \class TMVA::PDEFoamDiscriminantDensity
35\ingroup TMVA
36
37This is a concrete implementation of PDEFoam. Density(...)
38estimates the discriminant density at a given phase-space point
39using range-searching. The discriminant D is defined as
40
41 D = #events with given class / total number of events
42*/
44
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
57
58////////////////////////////////////////////////////////////////////////////////
59
64
65////////////////////////////////////////////////////////////////////////////////
66/// User constructor:
67///
68/// Parameters:
69///
70/// - box - size of the range-searching box (n-dimensional
71/// std::vector)
72///
73/// - cls - event class used for the range-searching
74
80
81////////////////////////////////////////////////////////////////////////////////
82/// Copy constructor
83
89
90////////////////////////////////////////////////////////////////////////////////
91/// This function is needed during the foam buildup. It returns the
92/// average number density of events of type fClass within the
93/// range-searching volume (specified by fBox).
94///
95/// Parameters:
96///
97/// - xev - event vector (in [fXmin,fXmax]) to place the box at
98///
99/// - event_density - here the event density is stored
100///
101/// Returns:
102///
103/// Number of events (event weights) of type fClass, which were
104/// found in the range-searching volume at point 'xev', divided by
105/// the box volume.
106
108{
109 if (!fBst)
110 Log() << kFATAL << "<PDEFoamDiscriminantDensity::Density()> Binary tree not set!" << Endl;
111
112 //create volume around point to be found
113 std::vector<Double_t> lb(GetBox().size());
114 std::vector<Double_t> ub(GetBox().size());
115
116 // probe volume relative to hypercube with edge length 1:
117 const Double_t probevolume_inv = 1.0 / GetBoxVolume();
118
119 // set upper and lower bound for search volume
120 for (UInt_t idim = 0; idim < GetBox().size(); ++idim) {
121 lb[idim] = xev[idim] - GetBox().at(idim) / 2.0;
122 ub[idim] = xev[idim] + GetBox().at(idim) / 2.0;
123 }
124
125 TMVA::Volume volume(&lb, &ub); // volume to search in
126 std::vector<const TMVA::BinarySearchTreeNode*> nodes; // BST nodes found
127
128 // do range searching
129 const Double_t sumOfWeights = fBst->SearchVolume(&volume, &nodes);
130
131 // store density based on total number of events
132 event_density = nodes.size() * probevolume_inv;
133
134 Double_t n_sig = 0; // number of signal events found
135 // calc number of signal events in nodes
136 for (std::vector<const TMVA::BinarySearchTreeNode*>::const_iterator it = nodes.begin();
137 it != nodes.end(); ++it) {
138 if ((*it)->GetClass() == fClass) // signal node
139 n_sig += (*it)->GetWeight();
140 }
141
142 // return: (n_sig/n_total) / (cell_volume)
143 return (n_sig / (sumOfWeights + 0.1)) * probevolume_inv;
144}
Cppyy::TCppType_t fClass
size_t size(const MatrixT &matrix)
retrieve the size of a square matrix
ROOT::Detail::TRangeCast< T, true > TRangeDynCast
TRangeDynCast is an adapter class that allows the typed iteration through a TCollection.
This is an abstract class, which provides an interface for a PDEFoam density estimator.
This is a concrete implementation of PDEFoam.
Double_t Density(std::vector< Double_t > &Xarg, Double_t &event_density) override
This function is needed during the foam buildup.
Volume for BinarySearchTree.
Definition Volume.h:47
void box(Int_t pat, Double_t x1, Double_t y1, Double_t x2, Double_t y2)
Definition fillpatterns.C:1
MsgLogger & Endl(MsgLogger &ml)
Definition MsgLogger.h:148