Version:
[ ReleaseNotes ] [ 1.0 ] [ 1.1 ] [ 2.0 ] [ 3.0 ] [ 3.1 ] [ 3.2 ] [ 4.0 ] [ 4.0.p1 ] [ 4.0.p2 ] [ 4.1 ] [ 4.1.p1 ] [ 5.0 ] [ 5.0.p1 ] [ 5.1 ] [ 5.1.p1 ] [ 5.2 ] [ 5.2.p1 ] [ 5.2.p2 ] [ 6.0 ] [ 6.0.p1 ] [ 6.1 ] [ 6.2 ] [ 6.2.p1 ] [ 6.2.p2 ] [ 7.0 ] [ 7.0.p1 ] [ 7.1 ] [ 7.1.p1 ] [ 8.0 ] [ 8.0.p1 ] [ 8.1 ] [ 8.1.p1 ] [ 8.1.p2 ] [ 8.2 ] [ 8.2.p1 ] [ 8.3 ] [ 8.3.p1 ] [ 8.3.p2 ] [ 9.0 ] [ 9.0.p1 ] [ 9.0.p2 ] [ 9.1 ] [ 9.1.p1 ] [ 9.1.p2 ] [ 9.1.p3 ] [ 9.2 ] [ 9.2.p1 ] [ 9.2.p2 ] [ 9.2.p3 ] [ 9.2.p4 ] [ 9.3 ] [ 9.3.p1 ] [ 9.3.p2 ] [ 9.4 ] [ 9.4.p1 ] [ 9.4.p2 ] [ 9.4.p3 ] [ 9.4.p4 ] [ 9.5 ] [ 9.5.p1 ] [ 9.5.p2 ] [ 9.6 ] [ 9.6.p1 ] [ 9.6.p2 ] [ 9.6.p3 ] [ 9.6.p4 ] [ 10.0 ] [ 10.0.p1 ] [ 10.0.p2 ] [ 10.0.p3 ] [ 10.0.p4 ] [ 10.1 ] [ 10.1.p1 ] [ 10.1.p2 ] [ 10.1.p3 ] [ 10.2 ] [ 10.2.p1 ] [ 10.2.p2 ] [ 10.2.p3 ] [ 10.3 ] [ 10.3.p1 ] [ 10.3.p2 ] [ 10.3.p3 ] [ 10.4 ] [ 10.4.p1 ] [ 10.4.p2 ] [ 10.4.p3 ] [ 10.5 ] [ 10.5.p1 ] [ 10.6 ] [ 10.6.p1 ] [ 10.6.p2 ] [ 10.6.p3 ] [ 10.7 ] [ 10.7.p1 ] [ 10.7.p2 ] [ 10.7.p3 ] [ 10.7.p4 ] [ 11.0 ] [ 11.0.p1 ] [ 11.0.p2 ] [ 11.0.p3, ] [ 11.0.p4 ] [ 11.1 ] [ 11.1.1 ] [ 11.1.2 ] [ 11.1.3 ] [ 11.2 ] [ 11.2.1 ] [ 11.2.2 ] [ 11.3.0 ]
1
2 =========================================================
3 Geant4 - an Object-Oriented Toolkit for Simulation in HEP
4 =========================================================
5
6 ExampleP01
7 ----------
8
9 General description
10 -------------------
11
12 This example shows how to store produced hits in a file using
13 the 'reflection' technique for persistency provided by the Reflex tool
14 included in ROOT. The Reflex tool allows to create a dictionary
15 for the hit class, making then possible to save hit objects in a .root
16 file. The general simulation setup (geometry, physics list, user
17 actions, etc...) is taken from ExampleN02.
18
19 The provided makefile produces two executables: 'exampleP01' and
20 'readHits'. The first one is the actual Geant4 simulation application
21 with hits persistency. The second one, is just a simple 'reader' for
22 the produced .root file (you need to specify the name of the .root
23 file as argument).
24
25
26 Building and running the example
27 --------------------------------
28
29 This examples requires the ROOT toolkit of version 6 to be installed. The
30 provided CMake file checks for the existence of the package and its version.
31 Once the CMake configuration has been succesfully done, the two executables
32 for this example (exampleP01, readHits) should be built using make
33 (in your CMake build directory):
34
35 make
36
37 When the example is run (using the provided run.mac macro file) ten
38 events are generated and the produced hits will be stored in
39 the hits.root file. In addition, the hits will be printed out on the
40 screen so one can then compare them with the 'reader' output.
41
42 In order to read the persistified hits, a small 'reader' application
43 has been implemented. It can be run in the following way:
44
45 <my_binary_directory>/readHits hits.root
46
47 where the argument is the name of the file to be read. All the hits
48 saved in that file will be then read and printed on the screen.
49
50 In addition to that the readHits.C ROOT macro file is provides, which
51 illustrates how one can read the hits file directly from the ROOT
52 prompt.
53
54
55 Remark on dictionary generation
56 -------------------------------
57
58 The dictionary is generated by ${ROOTSYS}/bin/genreflex
59 tool. The arguments that will be used by this tool are configured
60 in CMakeLists.txt using the CMake function REFLEX_GENERATE_DICTIONARY
61 provided by ROOT. They include the header file including headers for
62 all the classes we want to generate the dictionary, and additionally,
63 a so called selection file (xml). The role of this file is to
64 specify which classes we want to generate the dictionary for. The
65 selection file for our dictionary is in xml/ directory. Please refer
66 to genreflex manual for more details concerning the usage of that
67 tool.
68
69 Concerning generating dictionary for the Geant4 objects, there are
70 also two technical remarks that need to be made here.
71 The Reflex tool requires all the templated classes to be
72 explicitely used somewhere in the included header files in order for
73 the generation of the dictionary to be possible. For those templated
74 classes for which it is not the case, the problem can be very easily
75 solved by instaciating them in the headerfile which is given to
76 genreflex (see includes/ExP01Classes.hh) as argument.
77 The second remark is that there is an unfortunate clash of names as
78 far as G4String class is concerned. The header of G4String class
79 defines __G4String which happens to be the name of a variable used
80 within the generated dictionary code. The solution for that is to do
81 #undef __G4String in include/ExP01Classes.hh file.
82
83
