As molecular modelers, we often encounter scenarios where the default setup of a tool doesn’t entirely fit our requirements. A great example is when you’re working with GROMACS and need a specific version or configuration for reproducibility or compatibility with your system. If you’re using the GROMACS Wizard in SAMSON, you’ll be glad to know that it offers the flexibility to use custom GROMACS installations. Let’s dive into how this works!
Why Would You Customize Your GROMACS Setup?
The GROMACS Wizard already comes packaged with one of the latest versions of GROMACS, providing a ready-to-go setup for your molecular dynamics tasks. However, there are cases where having control over the specific version and configuration is essential:
- Reproducibility: Research often requires you to use the same version of GROMACS across simulations to ensure consistency.
- System-specific Optimization: Leveraging an existing GROMACS installation on your machine might provide better performance tailored to your hardware.
- Compatibility: Some projects may rely on certain features or force fields available only in specific versions of GROMACS.
Setting Up a Custom GROMACS Version
To use a locally installed version, you’ll need to configure it in SAMSON’s GROMACS Wizard. Here’s how:
- Open the GROMACS Wizard and click the Settings button at the top.
- In the settings menu, locate and enable the Use a different GROMACS version option.
- Provide the required paths:
- GROMACS executable: Use the
gmx.exepath on Windows orgmxpath on Linux/macOS by clicking on the
button. SAMSON will display the version of the chosen executable to confirm if it’s valid. - Force fields folder: Specify the directory containing your forcefield.ff files (e.g., $HOME/gromacs/share/top/ on Linux/macOS).
- GROMACS executable: Use the

Important Notes
While customizing GROMACS can be powerful, here are a few things to keep in mind:
- This setup applies only to local computations. Cloud jobs will not use your custom settings.
- If your goal is reproducibility, decide in advance the exact GROMACS version and force-field directory you’ll be using to avoid inconsistencies.
What’s Next?
Once you’ve configured your custom GROMACS setup, you can return to the GROMACS Wizard and launch calculations with your selected executable and performance parameters. Whether you’re running short simulations or extensive molecular dynamics jobs, this flexibility ensures your workflow is streamlined and tailored to your needs.
For detailed instructions and additional options, visit the official documentation page.
SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON at https://www.samson-connect.net.
