Multi-threading on the example chem2

Getting Started
1

Hi there,

I tried to run multi-threading on the example - chem2
But I found whatever threads number I set, it always ran on one core.
I can’t figure out why.

  1. I used Geant4.10.03.

  2. The ways I tried to set threads was
    export G4FORCENUMBEROFTHREADS=10
    or
    ./chem2 -mt 10

  3. The printed messages were:

Geant4 version Name: geant4-10-03-patch-03 [MT] (20-October-2017)
<< in Multi-threaded mode >>
Copyright : Geant4 Collaboration
Reference : NIM A 506 (2003), 250-303
WWW : http://cern.ch/geant4

### Number of threads is forced to 10 by Environment variable G4FORCENUMBEROFTHREADS.
===== Chem2 is started with 10 threads =====

-------- WWWW ------- G4Exception-START -------- WWWW -------
*** G4Exception : Run0113

  1. When running, only one chem2 process was shown by the top command

image
image827×351 43.9 KB

Thanks for the helping.

2

Multi-threading (not multi-processing) can be seen in the physical stage

image
image938×537 34.7 KB

Only ONE thread worked for the chemical stage no matter how many threads I created.

G4WT12 > Physics stage ends
G4WT12 > *** G4Scheduler starts processing
G4WT12 > At time : 1 ps Reaction : H^0 (-10843) + OH^0 (-10148) -> No product
G4WT12 > At time : 1 ps Reaction : OH^0 (-10682) + OH^0 (-9901) -> H2O2^0 (-10976)
G4WT12 > At time : 1 ps Reaction : OH^0 (-10024) + OH^0 (-10509) -> H2O2^0 (-10977)
G4WT12 > At time : 1 ps Reaction : OH^0 (-10485) + OH^0 (-10486) -> H2O2^0 (-10978)
G4WT12 > At time : 1 ps Reaction : OH^-1 (-5544) + H3O^1 (-6713) -> No product
G4WT12 > At time : 1 ps Reaction : H3O^1 (-8111) + OH^-1 (-10982) -> No product
G4WT12 > At time : 1.1 ps Reaction : OH^0 (-10586) + OH^0 (-10585) -> H2O2^0 (-10985)
G4WT12 > At time : 1.2 ps Reaction : OH^0 (-10502) + OH^0 (-10955) -> H2O2^0 (-10986)
G4WT12 > At time : 1.2 ps Reaction : OH^0 (-9801) + OH^0 (-10860) -> H2O2^0 (-10987)
G4WT12 > At time : 1.2 ps Reaction : OH^0 (-10038) + OH^0 (-9889) -> H2O2^0 (-10988)
:
:
G4WT12 > At time : 165.4 ns Reaction : H3O^1 (-6801) + e_aq^-1 (-743) -> H^0 (-12430)
G4WT12 > At time : 165.7 ns Reaction : H3O^1 (-5819) + OH^-1 (-12355) -> No product
G4WT12 > At time : 166.7 ns Reaction : H3O^1 (-5779) + e_aq^-1 (-5208) -> H^0 (-12431)
G4WT12 > At time : 167.4 ns Reaction : OH^0 (-8696) + e_aq^-1 (-1166) -> OH^-1 (-12432)
G4WT12 > At time : 167.6 ns Reaction : OH^-1 (-11938) + H3O^1 (-8211) -> No product
G4WT12 > At time : 170.1 ns Reaction : H3O^1 (-7375) + e_aq^-1 (-5184) -> H^0 (-12433)
G4WT12 > At time : 171.4 ns Reaction : e_aq^-1 (-3168) + H^0 (-10031) -> OH^-1 (-12434) + H_2

3

I think the reason for only one thread for the chemical stage is because the particles interact each other in this stage, right?

4

Dear,

Have you solved the problem? I had the same problem.