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Running Simulations

This guide explains how to run simulations on an HPC system using MPI.

Prerequisites

Before running a simulation, ensure:

  • MPI is available in your environment
  • The project has been successfully built
  • Your input file is prepared (e.g., input_parameters)

Example Workflow

Below is a typical workflow for running a simulation:

# Set input file
input_file="input_parameters"

# Create output directory (must match `fileout` in input file)
mkdir -p output_dir

# Move to submission directory
cd $SLURM_SUBMIT_DIR

# Run simulation with MPI
# IMPORTANT: must use at least 2 processes (np >= 2), otherwise it will fail
mpirun -np 2 ../build/channel3D "$input_file"

Notes

  • The output_dir must match the fileout path specified in your input file.
  • The number of processes (-np) must be at least 2 — running with 1 will cause the simulation to fail.
  • Adjust -np to match the number of processes you want to run (≥ 2).
  • Ensure your MPI environment is properly loaded before executing the command.