1 | /////////////////////////////////////////////////////////////////////////////// |
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2 | // File: quadtree.cpp // |
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3 | // Description: source file for quadtree management (Cquadtree class) // |
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4 | // This file is part of the SISCone project. // |
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5 | // For more details, see http://projects.hepforge.org/siscone // |
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6 | // // |
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7 | // Copyright (c) 2006 Gavin Salam and Gregory Soyez // |
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8 | // // |
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9 | // This program is free software; you can redistribute it and/or modify // |
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10 | // it under the terms of the GNU General Public License as published by // |
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11 | // the Free Software Foundation; either version 2 of the License, or // |
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12 | // (at your option) any later version. // |
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13 | // // |
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14 | // This program is distributed in the hope that it will be useful, // |
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15 | // but WITHOUT ANY WARRANTY; without even the implied warranty of // |
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16 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // |
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17 | // GNU General Public License for more details. // |
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18 | // // |
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19 | // You should have received a copy of the GNU General Public License // |
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20 | // along with this program; if not, write to the Free Software // |
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21 | // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA // |
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22 | // // |
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23 | // $Revision:: 859 $// |
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24 | // $Date:: 2012-11-28 02:49:23 +0100 (Wed, 28 Nov 2012) $// |
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25 | /////////////////////////////////////////////////////////////////////////////// |
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26 | |
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27 | #include "quadtree.h" |
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28 | #include <math.h> |
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29 | #include <stdio.h> |
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30 | #include <iostream> |
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31 | |
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32 | namespace siscone{ |
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33 | |
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34 | using namespace std; |
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35 | |
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36 | /******************************************************************* |
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37 | * Cquadtree implementation * |
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38 | * Implementation of a 2D quadtree. * |
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39 | * This class implements the traditional two-dimensional quadtree. * |
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40 | * The elements at each node are of 'Cmomentum' type. * |
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41 | *******************************************************************/ |
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42 | |
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43 | // default ctor |
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44 | //-------------- |
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45 | Cquadtree::Cquadtree(){ |
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46 | v = NULL; |
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47 | |
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48 | children[0][0] = children[0][1] = children[1][0] = children[1][1] = NULL; |
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49 | has_child = false; |
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50 | } |
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51 | |
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52 | |
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53 | // ctor with initialisation (see init for details) |
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54 | //-------------------------- |
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55 | Cquadtree::Cquadtree(double _x, double _y, double _half_size_x, double _half_size_y){ |
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56 | v = NULL; |
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57 | |
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58 | children[0][0] = children[0][1] = children[1][0] = children[1][1] = NULL; |
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59 | has_child = false; |
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60 | |
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61 | init(_x, _y, _half_size_x, _half_size_y); |
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62 | } |
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63 | |
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64 | |
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65 | // default destructor |
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66 | // at destruction, everything is destroyed except |
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67 | // physical values at the leaves |
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68 | //------------------------------------------------ |
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69 | Cquadtree::~Cquadtree(){ |
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70 | if (has_child){ |
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71 | if (v!=NULL) delete v; |
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72 | delete children[0][0]; |
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73 | delete children[0][1]; |
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74 | delete children[1][0]; |
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75 | delete children[1][1]; |
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76 | } |
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77 | } |
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78 | |
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79 | |
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80 | /* |
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81 | * init the tree. |
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82 | * By initializing the tree, we mean setting the cell parameters |
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83 | * and preparing the object to act as a seed for a new tree. |
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84 | * - _x x-position of the center |
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85 | * - _y y-position of the center |
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86 | * - half_size_x half x-size of the cell |
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87 | * - half_size_y half y-size of the cell |
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88 | * return 0 on success, 1 on error. Note that if the cell |
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89 | * is already filled, we return an error. |
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90 | ******************************************************************/ |
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91 | int Cquadtree::init(double _x, double _y, double _half_size_x, double _half_size_y){ |
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92 | if (v!=NULL) |
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93 | return 1; |
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94 | |
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95 | centre_x = _x; |
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96 | centre_y = _y; |
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97 | half_size_x = _half_size_x; |
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98 | half_size_y = _half_size_y; |
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99 | |
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100 | return 0; |
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101 | } |
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102 | |
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103 | |
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104 | /* |
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105 | * adding a particle to the tree. |
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106 | * This method adds one vector to the quadtree structure which |
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107 | * is updated consequently. |
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108 | * - v vector to add |
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109 | * return 0 on success 1 on error |
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110 | ******************************************************************/ |
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111 | int Cquadtree::add(Cmomentum *v_add){ |
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112 | // Description of the method: |
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113 | // -------------------------- |
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114 | // the addition process goes as follows: |
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115 | // 1. check if the cell is empty, in which case, add the particle |
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116 | // here and leave. |
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117 | // 2. If there is a unique particle already inside, |
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118 | // (a) create children |
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119 | // (b) forward the existing particle to the appropriate child |
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120 | // 3. Add current particle to this cell and forward to the |
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121 | // adequate child |
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122 | // NOTE: we assume in the whole procedure that the particle is |
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123 | // indeed inside the cell ! |
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124 | |
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125 | // step 1: the case of empty cells |
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126 | if (v==NULL){ |
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127 | v = v_add; |
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128 | return 0; |
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129 | } |
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130 | |
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131 | // step 2: additional work if 1! particle already present |
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132 | // we use the fact that only 1-particle systems have no child |
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133 | if (!has_child){ |
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134 | double new_half_size_x = 0.5*half_size_x; |
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135 | double new_half_size_y = 0.5*half_size_y; |
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136 | // create children |
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137 | children[0][0] = new Cquadtree(centre_x-new_half_size_x, centre_y-new_half_size_y, |
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138 | new_half_size_x, new_half_size_y); |
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139 | children[0][1] = new Cquadtree(centre_x-new_half_size_x, centre_y+new_half_size_y, |
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140 | new_half_size_x, new_half_size_y); |
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141 | children[1][0] = new Cquadtree(centre_x+new_half_size_x, centre_y-new_half_size_y, |
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142 | new_half_size_x, new_half_size_y); |
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143 | children[1][1] = new Cquadtree(centre_x+new_half_size_x, centre_y+new_half_size_y, |
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144 | new_half_size_x, new_half_size_y); |
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145 | |
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146 | has_child = true; |
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147 | |
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148 | // forward to child |
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149 | //? The following line assumes 'true'==1 and 'false'==0 |
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150 | // Note: v being a single particle, eta and phi are correct |
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151 | children[v->eta>centre_x][v->phi>centre_y]->add(v); |
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152 | |
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153 | // copy physical params |
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154 | v = new Cmomentum(*v); |
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155 | } |
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156 | |
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157 | // step 3: add new particle |
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158 | // Note: v_add being a single particle, eta and phi are correct |
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159 | children[v_add->eta>centre_x][v_add->phi>centre_y]->add(v_add); |
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160 | *v+=*v_add; |
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161 | |
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162 | return 0; |
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163 | } |
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164 | |
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165 | |
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166 | /* |
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167 | * circle intersection. |
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168 | * computes the intersection with a circle of given centre and radius. |
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169 | * The output takes the form of a quadtree with all squares included |
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170 | * in the circle. |
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171 | * - cx circle centre x coordinate |
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172 | * - cy circle centre y coordinate |
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173 | * - cR2 circle radius SQUARED |
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174 | * return the checksum for the intersection |
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175 | ******************************************************************/ |
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176 | Creference Cquadtree::circle_intersect(double cx, double cy, double cR2){ |
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177 | // Description of the method: |
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178 | // -------------------------- |
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179 | // 1. check if cell is empty => no intersection |
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180 | // 2. if cell has 1! particle, check if it is inside the circle. |
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181 | // If yes, add it and return, if not simply return. |
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182 | // 3. check if the circle intersects the square. If not, return. |
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183 | // 4. check if the square is inside the circle. |
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184 | // If yes, add it to qt and return. |
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185 | // 5. check intersections with children. |
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186 | |
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187 | // step 1: if there is no particle inside te square, no reason to go further |
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188 | if (v==NULL) |
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189 | return Creference(); |
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190 | |
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191 | double dx, dy; |
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192 | |
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193 | // step 2: if there is only one particle inside the square, test if it is in |
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194 | // the circle, in which case return associated reference |
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195 | if (!has_child){ |
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196 | // compute the distance |
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197 | // Note: v has only one particle => eta and phi are defined |
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198 | dx = cx - v->eta; |
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199 | dy = fabs(cy - v->phi); |
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200 | if (dy>M_PI) |
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201 | dy -= 2.0*M_PI; |
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202 | |
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203 | // test distance |
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204 | if (dx*dx+dy*dy<cR2){ |
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205 | return v->ref; |
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206 | } |
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207 | |
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208 | return Creference(); |
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209 | } |
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210 | |
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211 | // step 3: check if there is an intersection |
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212 | //double ryp, rym; |
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213 | double dx_c, dy_c; |
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214 | |
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215 | // store distance with the centre of the square |
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216 | dx_c = fabs(cx-centre_x); |
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217 | dy_c = fabs(cy-centre_y); |
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218 | if (dy_c>M_PI) dy_c = 2.0*M_PI-dy_c; |
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219 | |
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220 | // compute (minimal) the distance (pay attention to the periodicity in phi). |
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221 | dx = dx_c-half_size_x; |
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222 | if (dx<0) dx=0; |
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223 | dy = dy_c-half_size_y; |
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224 | if (dy<0) dy=0; |
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225 | |
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226 | // check the distance |
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227 | if (dx*dx+dy*dy>=cR2){ |
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228 | // no intersection |
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229 | return Creference(); |
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230 | } |
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231 | |
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232 | // step 4: check if included |
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233 | |
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234 | // compute the (maximal) distance |
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235 | dx = dx_c+half_size_x; |
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236 | dy = dy_c+half_size_y; |
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237 | if (dy>M_PI) dy = M_PI; |
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238 | |
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239 | // compute the distance |
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240 | if (dx*dx+dy*dy<cR2){ |
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241 | return v->ref; |
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242 | } |
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243 | |
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244 | // step 5: the square is not fully in. Recurse to children |
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245 | return children[0][0]->circle_intersect(cx, cy, cR2) |
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246 | + children[0][1]->circle_intersect(cx, cy, cR2) |
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247 | + children[1][0]->circle_intersect(cx, cy, cR2) |
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248 | + children[1][1]->circle_intersect(cx, cy, cR2); |
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249 | } |
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250 | |
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251 | |
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252 | /* |
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253 | * output a data file for drawing the grid. |
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254 | * This can be used to output a data file containing all the |
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255 | * grid subdivisions. The file contents is as follows: |
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256 | * first and second columns give center of the cell, the third |
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257 | * gives the size. |
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258 | * - flux opened stream to write to |
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259 | * return 0 on success, 1 on error |
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260 | ******************************************************************/ |
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261 | int Cquadtree::save(FILE *flux){ |
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262 | |
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263 | if (flux==NULL) |
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264 | return 1; |
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265 | |
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266 | if (has_child){ |
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267 | fprintf(flux, "%e\t%e\t%e\t%e\n", centre_x, centre_y, half_size_x, half_size_y); |
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268 | children[0][0]->save(flux); |
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269 | children[0][1]->save(flux); |
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270 | children[1][0]->save(flux); |
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271 | children[1][1]->save(flux); |
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272 | } |
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273 | |
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274 | return 0; |
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275 | } |
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276 | |
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277 | |
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278 | /* |
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279 | * output a data file for drawing the tree leaves. |
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280 | * This can be used to output a data file containing all the |
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281 | * tree leaves. The file contents is as follows: |
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282 | * first and second columns give center of the cell, the third |
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283 | * gives the size. |
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284 | * - flux opened stream to write to |
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285 | * return 0 on success, 1 on error |
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286 | ******************************************************************/ |
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287 | int Cquadtree::save_leaves(FILE *flux){ |
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288 | |
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289 | if (flux==NULL) |
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290 | return 1; |
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291 | |
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292 | if (has_child){ |
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293 | if (children[0][0]!=NULL) children[0][0]->save_leaves(flux); |
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294 | if (children[0][1]!=NULL) children[0][1]->save_leaves(flux); |
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295 | if (children[1][0]!=NULL) children[1][0]->save_leaves(flux); |
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296 | if (children[1][1]!=NULL) children[1][1]->save_leaves(flux); |
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297 | } else { |
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298 | fprintf(flux, "%e\t%e\t%e\t%e\n", centre_x, centre_y, half_size_x, half_size_y); |
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299 | } |
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300 | |
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301 | return 0; |
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302 | } |
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303 | |
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304 | } |
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