`exe` file — Execution script for running ReaxFF

The exe file is a user-provided execution script responsible for:

Preparing the run directory
Copying input files to the correct locations
Calling the ReaxFF executable
Optionally collecting or post-processing output files

The script is typically written as a UNIX shell script and executed from the command line.

Purpose of the `exe` script

ReaxFF itself does not manage file locations or job setup. Instead, the exe script acts as a lightweight workflow driver that:

Copies user input files into the working directory
Maps human-readable filenames to ReaxFF’s internal fort.# units
Launches the ReaxFF binary
(Optionally) copies output files to organized locations

Users with experience in UNIX shell scripting often customize this script to match their local environment, job scheduler, or file layout.

File name mapping and ReaxFF conventions

Although this manual refers to input files using descriptive names such as geo and ffield, ReaxFF internally expects these files under specific Fortran unit numbers:

Logical name	ReaxFF unit	Notes
`geo`	`fort.3`	Geometry input
`ffield`	`fort.4`	Force field definition
`control`	hard-coded	Read directly by name
`models.in`	hard-coded	Model list
`trainset.in`	hard-coded	Training set
`tregime.in`	hard-coded	Temperature regime

Only geo and ffield need to be explicitly mapped to fort.# files by the exe script.
Other inputs are opened by ReaxFF using fixed filenames and must not be renamed.

Example 2.10: UNIX `exe` script for running ReaxFF

Figure 1 shows an example exe script used by the original author to run ReaxFF from the UNIX command line.

#!/bin/sh

# Example ReaxFF execution script

# Clean previous run
rm -f fort.*

# Copy input files
cp geo      fort.3
cp ffield   fort.4

# Run ReaxFF
./reaxff.x

# Optional: collect outputs
mkdir -p output
cp fort.* output/

This example is intentionally minimal. Production workflows often add: - Error handling - Timestamped run directories - MPI execution (mpirun, srun) - Scheduler integration (SLURM, PBS) - Automatic post-processing

Customization guidelines

When adapting the exe script:

Ensure geo → fort.3 and ffield → fort.4 mappings are correct
Do not rename files that ReaxFF opens by hard-coded names
Confirm the correct ReaxFF executable (reaxff.x) is called
Use absolute paths if running from batch systems or job schedulers

Relation to modern workflows

While the traditional exe script is effective for manual runs, modern tools (including ReaxKit) often replace it with:

Python-based launchers
Structured directory management
Automated post-processing pipelines

Nevertheless, understanding the exe script is essential for interpreting legacy ReaxFF workflows and reproducing published results.

exe file — Execution script for running ReaxFF