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geant4/examples/extended/parallel/MPI/README.md
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2016-06-09 17:01:34 +02:00

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Geant4 MPI Interface
====================
Author:
Koichi Murakami (KEK) / Koichi.Murakami@kek.jp
About the interface
===================
G4MPI is a native interface with MPI libraries. The directory contains
a Geant4 UI library and a couple of parallelized examples.
Using this interface, users applications can be parallelized with
different MPI compliant libraries, such as OpenMPI, LAM/MPI, MPICH2 and so on.
System Requirements:
--------------------
### MPI Library
The MPI interface can work with MPI-compliant libraries,
such as Open MPI, LAM/MPI, Intel MPI etc.
For example, the information about Open MPI can be obtained from
http://www.open-mpi.org/
### CMake
CMake is used to build G4MPI library, that co-works with Geant4 build system.
### Optional
ROOT for histogramming/analysis
- - -
How to build G4MPI
==================
To build G4MPI library, use CMake on Geant4 library installed with CMake build.
Check `CMakeList.txt`, especially the following two variables
should be taken care to match your MPI library
eg.
set(CMAKE_CXX_COMPILER mpicxx)
#set(CMAKE_CXX_INCLUDE_PATH ) set if necessary
Follow these commands,
> cd source
> mkdir build
> cd build
> cmake -DGeant4_DIR=<your Geant4 install path>/lib64/Geant4-V.m.n ..
(V.m.n is the version of Geant4, eg. Geant4-9.6.0)
> make
> make install
The library and header files will be installed on the installation directory
of Geant4.
- - -
How to use
==========
How to make parallel applications
---------------------------------
An example of a main program:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~{.cc}
#include "G4MPImanager.hh"
#include "G4MPIsession.hh"
int main(int argc,char** argv)
{
// At first, G4MPImanager/G4MPIsession should be created.
G4MPImanager* g4MPI= new G4MPImanager(argc,argv);
// MPI session (G4MPIsession) instead of G4UIterminal
G4MPIsession* session= g4MPI-> GetMPIsession();
// user application setting
G4RunManager* runManager= new G4RunManager();
....
// After user application setting, just start a MPI session.
MPIsession treats both interactive and batch modes.
session-> SessionStart();
// Finally, terminate the program
delete g4MPI;
delete runManager;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
### Notes about session shell
LAM/MPI users can use "G4tcsh" as an interactive session shell.
For other users (Open MPI/MPICH2), plesae use G4csh (default).
In case of OpenMPI, *LD_LIBRARY_PATH* for OpenMPI runtime libraries
should be set at run time. Alternatively, you can add this path
to the dynamic linker configuration using `ldconfig`.
(needs sys-admin authorization)
MPI runtime Environment
-----------------------
1. Make hosts/cluster configuration of your MPI environment.
2. Launch MPI runtime environment, typically executing
`lamboot` (LAM) / `mpdboot` (MPICH2).
How to run
----------
For example,
> mpiexec -n # <your application>
Instead, `mpirun` command is more convenient for LAM users.
MPI G4UI commands
-----------------
G4UI commands handling the G4MPI interface are placed in /mpi/.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Command directory path : /mpi/
Guidance :
MPI control commands
Sub-directories :
Commands :
verbose * Set verbose level.
status * Show mpi status.
execute * Execute a macro file. (=/control/execute)
beamOn * Start a parallel run w/ thread.
.beamOn * Start a parallel run w/o thread.
masterWeight * Set weight for master node.
showSeeds * Show seeds of MPI nodes.
setMasterSeed * Set a master seed for the seed generator.
setSeed * Set a seed for a specified node.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
### Notes:
While "/run/beamOn" and "/mpi/beamOn" commands invoke beam-on in background,
so you can input UI commands even while event processing. Note that drawing
tracks in OpenGL with these commands causes a crash. Please use /mpi/.beamOn
command instead.
The original "/control/execute" and "/run/beamOn" are overwritten
with "/mpi/execute" and "/mpi/beamOn" commands respectively,
that are customized for the MPI interface.
- - -
Examples
========
There are a couple of examples for Geant4 MPI applications.
In some cases, you need to set some additional environment variables
for running examples:
- *G4LEDATA* : directory path for low energy EM data
- *G4LEVELGAMMADATA* : directory path for photon evapolation
- *G4SAIDXSDATA* : directory path for nucleon cross section data
For using ROOT libraries
- *ROOTSYS* : root path of the ROOT package
exMPI01
-------
A simple application.
**Configuration:**
- Geometry : chamber / calorimeter
- Primary : particle gun (200 MeV electron as default)
- Physics List : standard EM
**Features:**
- Particles are transported in a geometry without any scoring.
- Learn how to parallelized your G4 session.
exMPI02 (ROOT application)
--------------------------
An example of dosimetry in a water phantom.
**Configuration:**
- Geometry : water phantom
- Primary : broad beam (200 MeV proton)
- Physics List : FTFP_BERT
- Analysis : ROOT histogramming
**Features:**
- Score dose distribution in a water phantom.
- Learn how to parallelized your applications.
- Create a ROOT file containing histograms/trees in each node.