/*! @page  runmgr The Run Manager

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The run manager class in the most important class of the simulation since it is the class responsible for the course of the simulation. 
The code of the run manager is described in detail in the section " @ref howg4 ". 

In the main file, the user provides @ref useraction_intro "user action classes"  to the run manager. While running the simulation, it is to the run manager that the @ref beamOn "beamOn command" is sent to start the simulation. The run manager will initialize all the user classes and monitor the succession of the different phases of the simulation:
* - beginning of a run 
* - simulation of the different events
* - termination of the run
*.
The G4RunManager class works closely to the G4RunManagerKernel class which controls the kernel of \gf. It supervizes the initialization of the user classes, checks if the simulation can be ran and manages the status of the simulation.



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