Changeset 1208 for trunk/documents/UserDoc/DocBookUsersGuides/ForApplicationDeveloper/xml/TrackingAndPhysics/tracking.xml

Timestamp:

Nov 30, 2009, 3:52:24 PM (15 years ago)

Author:

garnier

Message:

CVS update

Location:

trunk/documents/UserDoc

Files:

• . (modified) (1 prop)
• DocBookUsersGuides (modified) (1 prop)
• DocBookUsersGuides/ForApplicationDeveloper (modified) (1 prop)
• DocBookUsersGuides/ForApplicationDeveloper/xml (modified) (1 prop)
• DocBookUsersGuides/ForApplicationDeveloper/xml/TrackingAndPhysics (modified) (1 prop)
• DocBookUsersGuides/ForApplicationDeveloper/xml/TrackingAndPhysics/tracking.xml (modified) (10 diffs)

trunk/documents/UserDoc/DocBookUsersGuides/ForApplicationDeveloper/xml/TrackingAndPhysics/tracking.xml

@@ -9 +9 @@
 <!--    Converted to DocBook: Katsuya Amako, Aug-2006         -->
 <!--    Changed by: Hisaya Kurashige, 01-Dec-2007             -->
+<!--    Changed by: Hisaya Kurashige, 18-Nov-2009             -->
 <!--                                                          -->
 <!-- ******************************************************** -->
@@ -56 +57 @@
 the different categories relevant to transporting a particle (for
 example, geometry and interactions in matter). Its public method
-<literal>Stepping()</literal> steers the stepping of the particle. The
-algorithm to handle one step is given below.
+<literal>Stepping()</literal> steers the stepping of the particle. 
+The algorithm to handle one step is given below.
 
 <orderedlist spacing="compact">
   <listitem><para>
-    The particle's velocity at the beginning of the step is
-    calculated.
-  </para></listitem>
+    If the particle stop (i.e. zero kinetic energy), each active atRest
+    process proposes a step length in time based on the interaction 
+    it describes. And the process proposing the smallest step length 
+    will be invoked.
+  </para></listitem>
+
   <listitem><para>
     Each active discrete or continuous process must propose a step
@@ -69 +73 @@
     step lengths is taken.
   </para></listitem>
+
   <listitem><para>
     The geometry navigator calculates "Safety", the distance to the
@@ -76 +81 @@
     geometrical calculations will be performed.
   </para></listitem>
+
   <listitem><para>
     If the minimum physical-step-length from the processes is
@@ -81 +87 @@
     re-calculated.
   </para></listitem>
+
   <listitem><para>
     The smaller of the minimum physical-step-length and the
     geometric step length is taken.
   </para></listitem>
+
   <listitem><para>
     All active continuous processes are invoked. Note that the
@@ -91 +99 @@
     sum of the contributions from these processes.
   </para></listitem>
-  <listitem><para>
-    The track is checked to see whether or not it has been
-    terminated by a continuous process.
-  </para></listitem>
+
   <listitem><para>
     The current track properties are updated before discrete
-    processes are invoked. This includes:
-
+    processes are invoked. In the same time, the secondary 
+    particles created by processes are stored in SecondaryList. 
+    The updated properties are:
     <itemizedlist spacing="compact">
       <listitem><para>
         updating the kinetic energy of the current track particle (note
-        that 'sumEnergyChange' is the sum of the new kinetic energy after
-        each continuos process was invoked, and NOT the sum of the energy
-        difference before and after the process invocation) and
+        that 'sumEnergyChange' is the sum of the energy difference 
+         before and after each process invocation) 
       </para></listitem>
       <listitem><para>
-        updating position and time.
+        updating position and time
+      </para></listitem>
+     </itemizedlist>    
+   </para></listitem>
+
+  <listitem><para>
+    The kinetic energy of the particle is checked to see whether 
+    or not  it has been terminated by a continuous process. 
+    If the kinetic energy goes down to zero, atRest processes 
+    will be applied at the next step if applicable. 
+  </para></listitem>
+
+  <listitem><para>
+    The discrete process is invoked. After the invocation,
+    <itemizedlist spacing="compact">
+      <listitem><para>
+        the energy, position and time of the current track particle 
+        are updated, and
+      </para></listitem>
+      <listitem><para>
+        the secondaries are stored in SecondaryList. 
       </para></listitem>
     </itemizedlist>
   </para></listitem>
-  <listitem><para>
-    The discrete process is invoked. After the invocation,
-
-    <itemizedlist spacing="compact">
-      <listitem><para>
-        the energy of the current track particle is updated, and
-      </para></listitem>
-      <listitem><para>
-        the secondaries from ParticleChange are stored in
-        SecondaryList. This includes constructing "G4Track" objects, and
-        setting their member data. Note that the stepping manager is
-        responsible for deleting secodaries from ParticleChange.
-      </para></listitem>
-    </itemizedlist>
-  </para></listitem>
+
   <listitem><para>
     The track is checked to see whether or not it has been
     terminated by the discrete process.
   </para></listitem>
+
   <listitem><para>
     "Safety" is updated.
   </para></listitem>
+
   <listitem><para>
     If the step was limited by the volume boundary, push the
     particle into the next volume.
   </para></listitem>
+
   <listitem><para>
     Invoke the user intervention <emphasis>G4UserSteppingAction</emphasis>.
   </para></listitem>
+
   <listitem><para>
     Handle hit information.
   </para></listitem>
+
   <listitem><para>
     Save data to Trajectory.
   </para></listitem>
+
   <listitem><para>
     Update the mean free paths of the discrete processes.
   </para></listitem>
+
   <listitem><para>
     If the parent particle is still alive, reset the maximum
     interaction length of the discrete process which has occurred.
   </para></listitem>
+
   <listitem><para>
     One step completed.
   </para></listitem>
+
 </orderedlist>
 </para>
+
+
+<!-- ******* Bridgehead ******* -->
+<bridgehead renderas='sect4'>
+What is a Process?
+</bridgehead>
+
+<para>
+Only processes can change information of <emphasis>G4Track</emphasis>
+and add secondary tracks via <literal>ParticleChange</literal>. 
+<emphasis>G4VProcess</emphasis> is a base class of all processes and
+it has 3 kinds of  <literal>DoIt</literal> and  
+<literal>GetPhysicalInteraction</literal> methods in order to
+describe interactions generically.
+If a user want to modify information of <emphasis>G4Track</emphasis>,
+he (or she) SHOULD create a special process for the purpose and 
+register the process to the particle.
+</para>
+
+<!-- ******* Bridgehead ******* -->
+<bridgehead renderas='sect4'>
+What is a Track?
+</bridgehead>
+
+<para>
+<emphasis>G4Track</emphasis> keeps 'current' information of the particle.
+(i.e. energy,momentum, position ,time and so on) and has 'static' 
+information (i.e. mass, charge, life and so on) also.  
+Note that <emphasis>G4Track</emphasis> keeps information at the beginning 
+of the step while the <literal>AlongStepDoIt</literal>s are being
+invoked for the step in progress.After finishing all 
+<literal>AlongStepDoIt</literal>s, <emphasis>G4Track</emphasis> 
+is updated.
+On the other hand, <emphasis>G4Track</emphasis> is
+updated after each invocation of a <literal>PostStepDoIt</literal>.
+</para>
+
 
 <!-- ******* Bridgehead ******* -->
@@ -176 +233 @@
 <!-- ******* Bridgehead ******* -->
 <bridgehead renderas='sect4'>
-What is a Track?
-</bridgehead>
-
-<para>
-<emphasis>G4Track</emphasis> keeps information on the final status of the
-particle after the completion of one step. This means that
-<emphasis>G4Track</emphasis> has information on the previous step while the
-<literal>AlongStepDoIt</literal>s are being invoked for the step in progress.
-Only after finishing all <literal>AlongStepDoIt</literal>s, will
-<emphasis>G4Track</emphasis> have the final information (e.g., the final
-position) for the step in progress. Also, <emphasis>G4Track</emphasis> will be
-updated after each invocation of a <literal>PostStepDoIt</literal>.
-</para>
+What is a ParticleChange?
+</bridgehead>
+
+<para>
+Processes do NOT change any information of <emphasis>G4Track</emphasis>
+directly in their <literal>DoIt</literal>. Instead, they proposes 
+changes as a result of interactions 
+by using <literal>ParticleChange</literal>.
+After each <literal>DoIt</literal>, <literal>ParticleChange</literal>
+updates <literal>PostStepPoint</literal> based on proposed changes. 
+Then, <emphasis>G4Track</emphasis> is updated 
+after finishing all <literal>AlongStepDoIt</literal>s and 
+after each <literal>PostStepDoIt</literal>.
+</para>
+
+
 
 </sect2>
@@ -459 +519 @@
 <para>
 Secondary particles are passed as <emphasis>G4Track</emphasis>s from a physics
-process to tracking. <emphasis>G4ParticleChange</emphasis> provides the following
+process to tracking. 
+<emphasis>G4ParticleChange</emphasis> provides the following
 four methods for a physics process:
 
@@ -481 +542 @@
 <para>
 In all but the first, the construction of <emphasis>G4Track</emphasis> is done in
-the methods using informaton given by the arguments.
+the methods using information given by the arguments.
 </para>
 
@@ -511 +572 @@
 kernel at specific points in the tracking. For details, see the
 <emphasis role="bold">Software Reference Manual</emphasis>.
+</para>
+
+<para>
+<emphasis role="bold">Note:</emphasis>
+Users SHOULD NOT (and CAN NOT) change <emphasis>G4Track</emphasis> 
+in  <literal>UserSteppingAction</literal>.
+Only the exception is the <literal>TrackStatus</literal>. 
 </para>