1 | <!-- ******************************************************** --> |
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2 | <!-- --> |
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3 | <!-- [History] --> |
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4 | <!-- Changed by: Katsuya Amako, 9-Jul-1998 --> |
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5 | <!-- Changed by: Katsuya Amako, 4-Aug-1998 --> |
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6 | <!-- Changed by: John Allison, 4-Aug-1998 --> |
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7 | <!-- Changed by: Katsuya Amako, 30-Nov-1998 --> |
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8 | <!-- Changed by: Dennis Wright, 27-Nov-2001 --> |
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9 | <!-- Proof read by: Joe Chuma, 2-Jul-1999 --> |
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10 | <!-- Converted to DocBook: Katsuya Amako, Aug-2006 --> |
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11 | <!-- --> |
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12 | <!-- ******************************************************** --> |
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13 | |
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14 | |
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15 | <!-- ******************* Section (Level#1) ****************** --> |
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16 | <sect1 id="sect.OptUAct"> |
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17 | <title> |
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18 | Optional User Actions |
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19 | </title> |
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20 | |
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21 | <para> |
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22 | There are five virtual classes whose methods the user may override |
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23 | in order to gain control of the simulation at various stages. Each |
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24 | method of each action class has an empty default implementation, |
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25 | allowing the user to inherit and implement desired classes and |
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26 | methods. Objects of user action classes must be registered with |
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27 | <literal>G4RunManager</literal>. |
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28 | </para> |
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29 | |
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30 | <!-- ******************* Section (Level#2) ****************** --> |
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31 | <sect2 id="sect.OptUAct.Usage"> |
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32 | <title> |
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33 | Usage of User Actions |
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34 | </title> |
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35 | |
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36 | <!-- ******* Bridgehead ******* --> |
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37 | <bridgehead renderas='sect4'> |
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38 | <literal>G4UserRunAction</literal> |
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39 | </bridgehead> |
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40 | |
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41 | <para> |
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42 | This class has three virtual methods which are invoked by |
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43 | <literal>G4RunManager</literal> for each run: |
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44 | |
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45 | <variablelist><title></title> |
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46 | <varlistentry> |
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47 | <term> |
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48 | <literal>GenerateRun()</literal> |
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49 | </term> |
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50 | <listitem><para> |
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51 | This method is invoked at the beginning of <literal>BeamOn</literal>. |
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52 | Because the user can inherit the class <literal>G4Run</literal> and create |
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53 | his/her own concrete class to store some information about the run, |
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54 | the <literal>GenerateRun()</literal> method is the place to instantiate such |
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55 | an object. It is also the ideal place to set variables which affect |
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56 | the physics table (such as production thresholds) for a particular |
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57 | run, because <literal>GenerateRun()</literal> is invoked before the |
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58 | calculation of the physics table. |
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59 | </para></listitem> |
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60 | </varlistentry> |
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61 | <varlistentry> |
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62 | <term> |
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63 | <literal>BeginOfRunAction()</literal> |
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64 | </term> |
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65 | <listitem><para> |
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66 | This method is invoked before entering the event loop. A |
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67 | typical use of this method would be to initialize and/or book |
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68 | histograms for a particular run. This method is invoked after the |
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69 | calculation of the physics tables. |
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70 | </para></listitem> |
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71 | </varlistentry> |
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72 | <varlistentry> |
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73 | <term> |
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74 | <literal>EndOfRunAction()</literal> |
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75 | </term> |
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76 | <listitem><para> |
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77 | This method is invoked at the very end of the run processing. |
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78 | It is typically used for a simple analysis of the processed run. |
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79 | </para></listitem> |
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80 | </varlistentry> |
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81 | </variablelist> |
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82 | </para> |
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83 | |
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84 | <para> |
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85 | <example id="programlist_OptUAct_1"> |
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86 | <title> |
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87 | <literal>G4UserRunAction</literal> |
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88 | </title> |
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89 | <programlisting> |
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90 | class G4UserRunAction |
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91 | { |
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92 | public: |
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93 | G4UserRunAction(); |
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94 | virtual ~G4UserRunAction(); |
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95 | |
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96 | public: |
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97 | virtual G4Run* GenerateRun(); |
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98 | virtual void BeginOfRunAction(const G4Run*); |
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99 | virtual void EndOfRunAction(const G4Run*); |
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100 | }; |
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101 | </programlisting> |
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102 | </example> |
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103 | </para> |
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104 | |
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105 | |
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106 | <!-- ******* Bridgehead ******* --> |
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107 | <bridgehead renderas='sect4'> |
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108 | <literal>G4UserEventAction</literal> |
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109 | </bridgehead> |
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110 | |
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111 | <para> |
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112 | This class has two virtual methods which are invoked by |
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113 | <literal>G4EventManager</literal> for each event: |
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114 | |
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115 | <variablelist><title></title> |
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116 | <varlistentry> |
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117 | <term> |
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118 | <literal>beginOfEventAction()</literal> |
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119 | </term> |
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120 | <listitem><para> |
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121 | This method is invoked before converting the primary particles |
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122 | to <literal>G4Track</literal> objects. A typical use of this method |
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123 | would be to initialize and/or book histograms for a particular event. |
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124 | </para></listitem> |
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125 | </varlistentry> |
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126 | <varlistentry> |
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127 | <term> |
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128 | <literal>endOfEventAction()</literal> |
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129 | </term> |
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130 | <listitem><para> |
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131 | This method is invoked at the very end of event processing. It |
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132 | is typically used for a simple analysis of the processed event. |
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133 | If the user wants to keep the currently processing event until the |
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134 | end of the current run, the user can invoke |
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135 | <literal>fpEventManager->KeepTheCurrentEvent();</literal> |
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136 | so that it is kept in <emphasis>G4Run</emphasis> object. This should |
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137 | be quite useful if you simulate quite many events and want to |
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138 | visualize only the most interest ones after the long execution. |
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139 | Given the memory size of an event and its contents may be large, |
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140 | it is the user's responsibility not to keep unnecessary events. |
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141 | </para></listitem> |
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142 | </varlistentry> |
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143 | </variablelist> |
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144 | </para> |
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145 | |
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146 | <para> |
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147 | <example id="programlist_OptUAct_2"> |
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148 | <title> |
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149 | <literal>G4UserEventAction</literal> |
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150 | </title> |
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151 | |
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152 | <programlisting> |
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153 | class G4UserEventAction |
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154 | { |
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155 | public: |
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156 | G4UserEventAction() {;} |
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157 | virtual ~G4UserEventAction() {;} |
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158 | virtual void BeginOfEventAction(const G4Event*); |
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159 | virtual void EndOfEventAction(const G4Event*); |
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160 | protected: |
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161 | G4EventManager* fpEventManager; |
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162 | }; |
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163 | </programlisting> |
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164 | </example> |
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165 | </para> |
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166 | |
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167 | <!-- ******* Bridgehead ******* --> |
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168 | <bridgehead renderas='sect4'> |
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169 | <literal>G4UserStackingAction</literal> |
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170 | </bridgehead> |
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171 | |
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172 | <para> |
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173 | This class has three virtual methods, <literal>ClassifyNewTrack</literal>, |
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174 | <literal>NewStage</literal> and <literal>PrepareNewEvent</literal> which the |
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175 | user may override in order to control the various track stacking mechanisms. |
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176 | ExampleN04 could be a good example to understand the usage of this class. |
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177 | </para> |
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178 | |
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179 | <para> |
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180 | <literal>ClassifyNewTrack()</literal> is invoked by |
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181 | <literal>G4StackManager</literal> whenever a new <literal>G4Track</literal> |
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182 | object is "pushed" onto a stack by <literal>G4EventManager</literal>. |
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183 | <literal>ClassifyNewTrack()</literal> returns an enumerator, |
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184 | <literal>G4ClassificationOfNewTrack</literal>, whose value indicates to which |
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185 | stack, if any, the track will be sent. This value should be |
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186 | determined by the user. <literal>G4ClassificationOfNewTrack</literal> has |
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187 | four possible values: |
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188 | |
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189 | <itemizedlist spacing="compact"> |
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190 | <listitem><para> |
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191 | <literal>fUrgent</literal> - track is placed in the |
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192 | <emphasis>urgent</emphasis> stack |
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193 | </para></listitem> |
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194 | <listitem><para> |
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195 | <literal>fWaiting</literal> - track is placed in the |
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196 | <emphasis>waiting</emphasis> stack, and will not be simulated until |
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197 | the <emphasis>urgent</emphasis> stack is empty |
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198 | </para></listitem> |
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199 | <listitem><para> |
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200 | <literal>fPostpone</literal> - track is postponed to the next event |
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201 | </para></listitem> |
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202 | <listitem><para> |
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203 | <literal>fKill</literal> - the track is deleted immediately and not |
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204 | stored in any stack. |
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205 | </para></listitem> |
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206 | </itemizedlist> |
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207 | </para> |
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208 | |
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209 | <para> |
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210 | These assignments may be made based on the origin of the track |
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211 | which is obtained as follows: |
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212 | |
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213 | <informalexample> |
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214 | <programlisting> |
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215 | G4int parent_ID = aTrack->get_parentID(); |
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216 | </programlisting> |
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217 | </informalexample> |
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218 | |
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219 | where |
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220 | |
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221 | <itemizedlist spacing="compact"> |
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222 | <listitem><para> |
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223 | <literal>parent_ID = 0</literal> indicates a primary particle |
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224 | </para></listitem> |
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225 | <listitem><para> |
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226 | <literal>parent_ID > 0</literal> indicates a secondary particle |
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227 | </para></listitem> |
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228 | <listitem><para> |
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229 | <literal>parent_ID < 0</literal> indicates postponed particle from |
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230 | previous event. |
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231 | </para></listitem> |
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232 | </itemizedlist> |
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233 | </para> |
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234 | |
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235 | <para> |
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236 | <literal>NewStage()</literal> is invoked when the <emphasis>urgent</emphasis> |
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237 | stack is empty and the <emphasis>waiting</emphasis> stack contains at least one |
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238 | <literal>G4Track</literal> object. Here the user may kill or re-assign to |
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239 | different stacks all the tracks in the <emphasis>waiting</emphasis> stack by |
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240 | calling the <literal>stackManager->ReClassify()</literal> method which, in |
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241 | turn, calls the <literal>ClassifyNewTrack()</literal> method. If no user |
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242 | action is taken, all tracks in the <emphasis>waiting</emphasis> stack are |
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243 | transferred to the <emphasis>urgent</emphasis> stack. The user may also decide to |
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244 | abort the current event even though some tracks may remain in the |
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245 | <emphasis>waiting</emphasis> stack by calling <literal>stackManager->clear()</literal>. |
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246 | This method is valid and safe only if it is called from the |
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247 | <literal>G4UserStackingAction</literal> class. A global method of event |
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248 | abortion is |
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249 | |
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250 | <informalexample> |
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251 | <programlisting> |
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252 | G4UImanager * UImanager = G4UImanager::GetUIpointer(); |
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253 | UImanager->ApplyCommand("/event/abort"); |
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254 | </programlisting> |
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255 | </informalexample> |
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256 | </para> |
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257 | |
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258 | <para> |
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259 | <literal>PrepareNewEvent()</literal> is invoked at the beginning of each |
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260 | event. At this point no primary particles have been converted to |
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261 | tracks, so the <emphasis>urgent</emphasis> and <emphasis>waiting</emphasis> |
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262 | stacks are empty. However, there may be tracks in the |
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263 | <emphasis>postponed-to-next-event</emphasis> stack; |
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264 | for each of these the <literal>ClassifyNewTrack()</literal> method is |
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265 | called and the track is assigned to the appropriate stack. |
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266 | |
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267 | <example id="programlist_OptUAct_3"> |
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268 | <title> |
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269 | <literal>G4UserStackingAction</literal> |
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270 | </title> |
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271 | |
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272 | <programlisting> |
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273 | #include "G4ClassificationOfNewTrack.hh" |
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274 | |
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275 | class G4UserStackingAction |
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276 | { |
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277 | public: |
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278 | G4UserStackingAction(); |
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279 | virtual ~G4UserStackingAction(); |
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280 | protected: |
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281 | G4StackManager * stackManager; |
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282 | |
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283 | public: |
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284 | //--------------------------------------------------------------- |
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285 | // virtual methods to be implemented by user |
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286 | //--------------------------------------------------------------- |
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287 | // |
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288 | virtual G4ClassificationOfNewTrack |
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289 | ClassifyNewTrack(const G4Track*); |
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290 | // |
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291 | //--------------------------------------------------------------- |
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292 | // |
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293 | virtual void NewStage(); |
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294 | // |
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295 | //--------------------------------------------------------------- |
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296 | // |
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297 | virtual void PrepareNewEvent(); |
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298 | // |
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299 | //--------------------------------------------------------------- |
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300 | |
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301 | }; |
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302 | </programlisting> |
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303 | </example> |
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304 | </para> |
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305 | |
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306 | |
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307 | <!-- ******* Bridgehead ******* --> |
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308 | <bridgehead renderas='sect4'> |
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309 | <literal>G4UserTrackingAction</literal> |
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310 | </bridgehead> |
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311 | |
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312 | <para> |
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313 | <example id="programlist_OptUAct_4"> |
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314 | <title> |
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315 | <literal>G4UserTrackingAction</literal> |
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316 | </title> |
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317 | |
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318 | <programlisting> |
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319 | //--------------------------------------------------------------- |
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320 | // |
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321 | // G4UserTrackingAction.hh |
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322 | // |
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323 | // Description: |
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324 | // This class represents actions taken place by the user at each |
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325 | // end of stepping. |
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326 | // |
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327 | //--------------------------------------------------------------- |
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328 | |
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329 | /////////////////////////// |
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330 | class G4UserTrackingAction |
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331 | /////////////////////////// |
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332 | { |
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333 | |
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334 | //-------- |
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335 | public: |
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336 | //-------- |
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337 | |
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338 | // Constructor & Destructor |
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339 | G4UserTrackingAction(){}; |
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340 | virtual ~G4UserTrackingAction(){} |
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341 | |
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342 | // Member functions |
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343 | virtual void PreUserTrackingAction(const G4Track*){} |
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344 | virtual void PostUserTrackingAction(const G4Track*){} |
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345 | |
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346 | //----------- |
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347 | protected: |
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348 | //----------- |
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349 | |
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350 | // Member data |
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351 | G4TrackingManager* fpTrackingManager; |
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352 | |
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353 | }; |
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354 | </programlisting> |
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355 | </example> |
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356 | </para> |
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357 | |
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358 | |
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359 | <!-- ******* Bridgehead ******* --> |
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360 | <bridgehead renderas='sect4'> |
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361 | <literal>G4UserSteppingAction</literal> |
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362 | </bridgehead> |
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363 | |
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364 | <para> |
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365 | <example id="programlist_OptUAct_5"> |
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366 | <title> |
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367 | <literal>G4UserSteppingAction</literal> |
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368 | </title> |
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369 | |
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370 | <programlisting> |
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371 | //--------------------------------------------------------------- |
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372 | // |
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373 | // G4UserSteppingAction.hh |
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374 | // |
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375 | // Description: |
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376 | // This class represents actions taken place by the user at each |
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377 | // end of stepping. |
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378 | // |
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379 | //--------------------------------------------------------------- |
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380 | |
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381 | /////////////////////////// |
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382 | class G4UserSteppingAction |
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383 | /////////////////////////// |
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384 | { |
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385 | |
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386 | //-------- |
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387 | public: |
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388 | //-------- |
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389 | |
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390 | // Constructor and destructor |
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391 | G4UserSteppingAction(){} |
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392 | virtual ~G4UserSteppingAction(){} |
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393 | |
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394 | // Member functions |
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395 | virtual void UserSteppingAction(const G4Step*){} |
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396 | |
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397 | //----------- |
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398 | protected: |
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399 | //----------- |
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400 | |
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401 | // Member data |
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402 | G4SteppingManager* fpSteppingManager; |
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403 | |
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404 | }; |
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405 | </programlisting> |
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406 | </example> |
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407 | </para> |
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408 | |
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409 | </sect2> |
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410 | |
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411 | <!-- ******************* Section (Level#2) ****************** --> |
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412 | <sect2 id="sect.OptUAct.EngyConsv"> |
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413 | <title> |
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414 | Killing Tracks in User Actions and Energy Conservation |
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415 | </title> |
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416 | |
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417 | <para> |
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418 | In either of user action classes described in the previous section, |
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419 | the user can implement an unnatural/unphysical action. A typical |
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420 | example is to kill a track, which is under the simulation, in the |
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421 | user stepping action. In this case the user have to be cautious of |
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422 | the total energy conservation. The user stepping action itself does |
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423 | not take care the energy or any physics quantity associated with |
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424 | the killed track. Therefore if the user want to keep the total |
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425 | energy of an event in this case, the lost track energy need to be |
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426 | recorded by the user. |
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427 | </para> |
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428 | |
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429 | <para> |
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430 | The same is true for user stacking or tracking actions. If the |
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431 | user has killed a track in these actions the all physics information |
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432 | associated with it would be lost and, for example, the total energy |
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433 | conservation be broken. |
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434 | </para> |
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435 | |
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436 | <para> |
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437 | If the user wants the Geant4 kernel to take care the total energy |
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438 | conservation automatically when he/she has killed artificially |
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439 | a track, the user has to use a killer process. For example if the |
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440 | user uses G4UserLimits and G4UserSpecialCuts process, energy of |
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441 | the killed track is added to the total energy deposit. |
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442 | </para> |
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443 | |
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444 | |
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445 | </sect2> |
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446 | </sect1> |
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