Running the Code - hyschive/gamer-fork GitHub Wiki

This page covers the following topics:

• Running Simulations
• Restarting from a Snapshot
• Terminating or Pausing Simulations
• Taking Notes

It is highly recommended that you first follow the demos given in Quick Start.

To run the code in a serial mode (i.e., no MPI and OpenMP), follow the steps below:

1. Compile the code (See Installation for details)

   1. Set CXX in the configuration file to a serial compiler (e.g., g++ or icpc)
   2. Set the following arguments when generating Makefile:
      • --mpi=false
      • --openmp=false
   3. Recompile the code by make clean; make

2. Set the runtime parameters (see Runtime Parameters for details)

   1. Put the required input files (e.g., Input__Parameter) in the same directory as the executable gamer
   2. Set parameters properly

3. Launch the code

   ./gamer

4. Check the outputs

   • Simulation progress → stdout
   • Simulation log files → Record__*
   • Simulation snapshots → Data_??????

Further readings:

• Enable MPI and OpenMP parallelization
• Enable GPU acceleration

To restart a simulation from a snapshot (e.g., Data_000123), do the following steps:

1. Set OPT__INIT=2
2. Create a soft link named RESTART to a targeted snapshot: ln -s Data_000123 RESTART
3. Run the code as usual

Typically, a simulation ends when reaching either END_T or END_STEP. One can also forcibly terminate a simulation by creating a file named STOP_GAMER_STOP (e.g., using touch STOP_GAMER_STOP) in the same directory as the executable gamer. The program will check the existence of this file after every root-level update. If it is detected, the program will output the final data (assuming at least one of the output options described in Outputs is enabled), delete the file STOP_GAMER_STOP, and then be terminated. Note that this functionality is supported only when the runtime parameter OPT__MANUAL_CONTROL is on.

Similarly, one can create a file named PAUSE_GAMER_PAUSE to pause a simulation. To resume it, simply delete this file.

One can put simulation notes in a text file named Input__Note. The content of this file will be automatically copied to the top of the log file Record__Note during code initialization. For example,

cat Input__Note

~ PUT YOUR SIMULATION NOTES HERE ~

./gamer
head Record__Note

Simulation Note
***********************************************************************************

~ PUT YOUR SIMULATION NOTES HERE ~

***********************************************************************************

• Installation
• Runtime Parameters