A production molecular dynamics run is where a prepared system begins generating the trajectory you want to analyze. But it is also an easy place to lose time: the wrong starting structure, mismatched coupling settings, or an import choice that does not fit your analysis can turn a completed simulation into a frustrating detour.
A simple way to reduce that risk is to treat production as three linked decisions: what you start from, what you ask the system to do, and what you bring back for inspection.
1. Start from the right state
Production should continue from a successfully equilibrated system whose temperature and density have stabilized. In GROMACS Wizard, the input can be either the GRO file from NPT equilibration (or a previous production run), or the corresponding equilibrated batch project.
If you are continuing the previous successful step, use the auto-fill button rather than locating the input manually. It can fill the path from the preceding project, helping avoid accidentally starting from an older structure. If you select a file yourself, pause to confirm it is the intended final structure from equilibration.
2. Carry equilibration choices forward
The production Parameters section contains frequently adjusted settings, including the integration time step and number of steps. Other GROMACS options are available through All…. Defaults provide a starting point, but production parameters should reflect the system and the purpose of the run—not simply the fact that a field has a default value.
One especially useful consistency check is to compare coupling settings with the equilibration stages. The documentation recommends keeping temperature coupling consistent with NVT equilibration, including the temperature used for velocity generation if that option is enabled. Likewise, check that pressure coupling corresponds to NPT equilibration. Position-restraint options are populated automatically based on the input system.
For learning or a quick workflow check, the tutorial sets the maximum number of steps to 50,000 so the example finishes quickly. Treat this as a tutorial setting, not a general recommendation for scientific production runs. If you need to reuse a carefully chosen parameter set, the Advanced parameters window lets you reset values, load them from an MDP file, or save them to an MDP file. Modified parameters are saved when SAMSON closes, so check them again when returning to a project.
3. Choose how to run before you launch
GROMACS Wizard supports three paths: generate inputs for use elsewhere, simulate locally on your PC, or simulate in the cloud. Local execution is convenient when your computer has the resources for the job. Cloud execution can suit larger systems, but requires computing credits. Generating inputs is useful when you want to run the prepared project on a cluster, for example.
After launching locally, monitor progress in the Output window or open Local jobs to check job status. You can continue using SAMSON and GROMACS Wizard while calculations run.
4. Make the import decision deliberately
When results are ready, GROMACS Wizard can offer options for importing the trajectory and generating plots. You can import the whole trajectory, just the last frame, or a selected range; you can also choose periodic-boundary-condition treatment and what to center the system on, such as the protein. Consider what you need next: a full trajectory supports inspection across time, while a single frame can be enough when you only need a final structure in the workspace.
Canceling the trajectory import does not delete the simulation results; the plots can still be generated. The results remain in the configured results folder, in a folder named with the launch date and time and the step suffix _md.
After the run, inspect the radius-of-gyration and RMSD plots alongside the trajectory. These are useful views of the simulation, not substitutes for deciding whether the run answers your scientific question. For pulling simulations, additional plots can show pull force and coordinates. Save plots you want to keep using the figure’s Save button.
Before you launch: confirm the equilibrated input, review coupling settings, choose a run destination, and decide what trajectory data you will need to inspect. That short pause can make the handoff from equilibration to analysis much smoother.
For the complete walkthrough, see the GROMACS Wizard production MD tutorial.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON.