GMX-CONVERT-TPR(1)

💖 gmx-convert-tpr 💖

okay bestie, welcome to gmx-convert-tpr, straight outta the GROMACS manual (GROMACS, that's the manual name, iykyk) — it's the little glow-up tool for your run-input files 💅

✨ NAME ✨

gmx-convert-tpr — make a modified run-input file 🎀

🦋 SYNOPSIS 🦋

gmx convert-tpr [-s [<.tpr/.gro/...>]] [-n [<.ndx>]]
             [-o [<.tpr/.gro/...>]] [-extend <time>] [-until <time>]
             [-nsteps <int>] [-[no]generate_velocities]
             [-velocity_temp <real>] [-velocity_seed <int>]

🌸 DESCRIPTION 🌸

so gmx convert-tpr can edit run-input files in three ways, no cap:

1. by modifying the number of steps in a run-input file with the options -extend, -until or -nsteps (and heads up: nsteps=-1 means unlimited number of steps 👑)
2. by creating a .tpx file for a subset of your original tpx file, which is lowkey so useful when you want to remove the solvent from your .tpx file, or when you want to make e.g. a pure Calpha .tpx file. note that you may need to use -nsteps -1 (or similar) to get this to work.

⚠️ WARNING: this .tpx file is not fully functional. like, it's giving incomplete. not all the way slay. 💀

3. by setting the charges of a specified group to zero. this is useful when doing free energy estimates using the LIE (Linear Interaction Energy) method ✨

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🎀 OPTIONS 🎀

💜 Options to specify input files:

• -s [<.tpr/.gro/...>] (topol.tpr) — the run-input file to modify: tpr gro g96 pdb brk ent 🫶
• -n [<.ndx>] (index.ndx) (Optional) — file containing additional index groups 🌈

💖 Options to specify output files:

• -o [<.tpr/.gro/...>] (tprout.tpr) (Optional) — the generated, modified run-input file: tpr gro g96 pdb brk ent ✨

🧚 Other options:

• -extend <time> (0) — extend runtime by this amount (ps)
• -until <time> (0) — extend runtime until this ending time (ps)
• -nsteps <int> (0) — change the number of steps remaining to be made
• -[no]generate_velocities (no) — reassign velocities, using a generated seed unless one is explicitly set
• -velocity_temp <real> (300) — temperature to use when generating velocities
• -velocity_seed <int> (-1) — random seed for velocities. if the value is -1, a new one is generated 🎲

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👀 SEE ALSO 👀

• gmx(1)

more info about GROMACS is available at http://www.gromacs.org/ 🦋

⭐ COPYRIGHT ⭐

2026, GROMACS development team

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and that's the whole vibe check bestie 🫶 this was GROMACS 2026.4, dated Oct 02, 2026 — go forth and modify those run-input files, you absolute icon 👑💖 periodt.