| Geant4 Cross Reference |
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4 Geant4 - an Object-Oriented Toolkit for S
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7 Tips how to run an example in multi-th
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10 Only migrated examples or user applications c
11 The instructions for migrating user applicati
12 and a short howto is available here:
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14 https://twiki.cern.ch/twiki/bin/view/Geant4/Q
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16 In this file, we give just useful tips for ru
17 (or user applications).
18
19 1) RUN EXAMPLE IN MULTI-THREADING MODE
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21 No special steps are needed to build an examp
22 The examples which has been migrated to multi
23 run in MT when they are built against the Gea
24 activated, otherwise they will run in sequent
25 Not migrated examples will run in sequential
26 Geant4 libraries built with MT mode activated
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28 The examples which do NOT support MT can be e
29 of code in main ():
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31 G4RunManager* runManager = new G4RunManager
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33 or
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35 auto* runManager = G4RunManagerFactory::Cre
36
37 2) SET NUMBER OF THREADS
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39 When the number of threads is not selected in
40 (which is actually 2) will be used. Another n
41 ways:
42
43 - in the code
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45 auto* runManager = ...;
46 runManager->SetNumberOfThreads(4);
47
48 - in a macro file via UI command added just b
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50 /run/numberOfThreads 4
51
52 - by setting the environment variable
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54 export G4FORCENUMBEROFTHREADS = 4
55 or
56 setenv G4FORCENUMBEROFTHREADS 4
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58 The environment variable value is forced and
59 call or a macro. A warning is issued in such
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61 3) OUTPUT FROM THREADS
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63 In MT processing each worker produces its out
64 on the screen. The messeges from threads are
65 G4WTi> where i is the thread number. Users c
66 and choose
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68 - to limit the output from threads to one sel
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70 /control/cout/ignoreThreadsExcept 0
71
72 - to redirect the output from threads in a fi
73
74 /control/cout/setCoutFile coutFileName
75 /control/cout/setCerrFile cerrFileName
76
77 - to buffer the output from each thread at a
78 thread is grouped and printed at the end of
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80 /control/cout/useBuffer true|false