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Reference Guide
PDEFoamEventDensity.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: PDEFoamEventDensity *
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 PDEFoamEventDensity::Density() does *
15 * this job. It *
16 * uses a binary search tree, filled with training events, in order to *
17 * provide this density. *
18 * *
19 * Authors (alphabetical): *
20 * Tancredi Carli - CERN, Switzerland *
21 * Dominik Dannheim - CERN, Switzerland *
22 * S. Jadach - Institute of Nuclear Physics, Cracow, Poland *
23 * Alexander Voigt - TU Dresden, Germany *
24 * Peter Speckmayer - CERN, Switzerland *
25 * *
26 * Copyright (c) 2008, 2010: *
27 * CERN, Switzerland *
28 * MPI-K Heidelberg, Germany *
29 * *
30 * Redistribution and use in source and binary forms, with or without *
31 * modification, are permitted according to the terms listed in LICENSE *
32 * (http://tmva.sourceforge.net/LICENSE) *
33 **********************************************************************************/
34
35/*! \class TMVA::PDEFoamEventDensity
36\ingroup TMVA
37This is a concrete implementation of PDEFoam. Density(...)
38estimates the event (weight) density at a given phase-space point
39using range-searching.
40*/
41
43
46#include "TMVA/MsgLogger.h"
48#include "TMVA/Types.h"
49#include "TMVA/Volume.h"
50
51#include "Rtypes.h"
52
53#include <cmath>
54#include <vector>
55
57
58////////////////////////////////////////////////////////////////////////////////
59
62{}
63
64////////////////////////////////////////////////////////////////////////////////
65/// User constructor
66///
67/// Parameters:
68///
69/// - box - size of sampling box
70
73{
74}
75
76////////////////////////////////////////////////////////////////////////////////
77/// Copy constructor
78
80 : PDEFoamDensityBase(distr)
81{
82}
83
84////////////////////////////////////////////////////////////////////////////////
85/// This function is needed during the foam buildup. It returns the
86/// event density within the range-searching volume (specified by
87/// fBox).
88///
89/// Parameters:
90///
91/// - xev - event vector (in [fXmin,fXmax]) to place the box at
92///
93/// - event_density - here the event density is stored
94///
95/// Returns:
96///
97/// Number of events (event weights), which were found in the
98/// range-searching volume at point 'xev', divided by the box
99/// volume.
100
101Double_t TMVA::PDEFoamEventDensity::Density(std::vector<Double_t> &xev, Double_t &event_density)
102{
103 if (!fBst)
104 Log() << kFATAL << "<PDEFoamEventDensity::Density()> Binary tree not found!" << Endl;
105
106 //create volume around point to be found
107 std::vector<Double_t> lb(GetBox().size());
108 std::vector<Double_t> ub(GetBox().size());
109
110 // probevolume relative to hypercube with edge length 1:
111 const Double_t probevolume_inv = 1.0 / GetBoxVolume();
112
113 // set upper and lower bound for search volume
114 for (UInt_t idim = 0; idim < GetBox().size(); ++idim) {
115 lb[idim] = xev[idim] - GetBox().at(idim) / 2.0;
116 ub[idim] = xev[idim] + GetBox().at(idim) / 2.0;
117 }
118
119 TMVA::Volume volume(&lb, &ub); // volume to search in
120 std::vector<const TMVA::BinarySearchTreeNode*> nodes; // BST nodes found
121
122 // do range searching
123 const Double_t sumOfWeights = fBst->SearchVolume(&volume, &nodes);
124
125 // store density based on total number of events
126 event_density = nodes.size() * probevolume_inv;
127
128 // return: N_total(weighted) / cell_volume
129 return (sumOfWeights + 0.1) * probevolume_inv;
130}
size_t size(const MatrixT &matrix)
retrieve the size of a square matrix
#define ClassImp(name)
Definition: Rtypes.h:375
This is an abstract class, which provides an interface for a PDEFoam density estimator.
This is a concrete implementation of PDEFoam.
virtual Double_t Density(std::vector< Double_t > &Xarg, Double_t &event_density)
This function is needed during the foam buildup.
Volume for BinarySearchTree.
Definition: Volume.h:47
@ kFATAL
Definition: Types.h:61
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
Double_t Log(Double_t x)
Returns the natural logarithm of x.
Definition: TMath.h:753