Deprecated functionality

Changes anticipated to GROMACS 2026 functionality

Functionality deprecated in GROMACS 2026

Generating angle constraints with grompp is deprecated

Google Native Client (NaCl) build deprecated

Last release of the sandbox has been 10 years ago and the support for NaCl has been removed from LLVM 22. Building option GMX_NACL is now deprecated in GROMACS.

Functionality deprecated in GROMACS 2025

MTTK pressure coupling is deprecated

Issue 5072

The TNG trajectory format is deprecated

The TNG file format will be removed in a future release. It will be replaced by the more widely used HDF5-based H5MD format. There will be at least one version of GROMACS supporting both H5MD and TNG to allow conversions between the two formats.

Issue 5225

Functionality deprecated in GROMACS 2024

The analysis tool gmx gyrate-legacy deprecated

gmx gyrate has been partly re-implemented in the modern GROMACS analysis framework. The old implementation is still available as gmx gyrate-legacy. Please plan to update to the new version. Please let the GROMACS developers know of desired functionality missing from, or broken in, the new implementation.

Issue 4927

The analysis tool gmx hbond-legacy deprecated

gmx hbond has been partly re-implemented in the modern GROMACS analysis framework. The old implementation is still available as gmx hbond-legacy. Please plan to update to the new version. Please let the GROMACS developers know of desired functionality missing from, or broken in, the new implementation.

Issue 4927

The analysis tools gmx sans and gmx saxs deprecated

gmx sans and gmx saxs has been partly re-implemented under new name gmx scattering in the modern GROMACS analysis framework. The old implementations are still available as gmx sans-legacy and gmx saxs-legacy. Please plan to update to the new version. Please let the GROMACS developers know of desired functionality missing from, or broken in, the new implementation.

Issue 4927

Functionality deprecated in GROMACS 2022

GMX_OPENCL_NB_CLUSTER_SIZE CMake variable deprecated in favor of GMX_GPU_NB_CLUSTER_SIZE

Both OpenCL and SYCL support different cluster sizes, so GMX_GPU_NB_CLUSTER_SIZE should be used going forward.

Guessing masses and atomic radii from atom names is deprecated

When atom masses or van-der-Waals radii are needed, we suggest building a proper GROMACS topology instead of using PDB files directly, even if the tool supports it.

Issue 3368 Issue 4288

Functionality deprecated in GROMACS 2021

mdrun -deffnm to be removed

This functionality is convenient when running very simple simulations, because it permits grouping of a set of files that then differ only their suffix. However, it does not work in the wider case of an mdrun module (or modules) writing multiple .xvg output files. The resulting filenames collide. That, and its interaction with checkpointing and appending, have led to quite a few bug reports.

Because users can use a folder to group files (a standard mechanism that they understand from experience outside of GROMACS), we can build and test better software for them if we remove the erstwhile convenience of mdrun -deffnm. Please update your workflows accordingly.

Issue 3818

OpenCL to be removed as a GPU framework

Since there are no prospects of an emerging GPU vendor in HPC needing OpenCL support, we intend to focus our efforts on CUDA, SYCL, and HIP for GPU acceleration in GROMACS. OpenCL support has been deprecated for a while, and will be removed in a future release.

Issue 3818

Support for version 1 of the hardware locality library hwloc

Version 2 has been supported in GROMACS for several years. The capabilities of newer hardware and hardware-support APIs are of most interest for GROMACS moving forward, so we should minimize our testing work and encourage clusters to upgrade older hwloc installations.

Issue 3818

Legacy API

The legacy installed headers have been deprecated for a while, however we wish to state more broadly that all headers found within the src directory tree of GROMACS are intended for internal consumption only, and are thus subject to change without notice. Further, the form and contents of the libgromacs library and related CMake targets may change as we move towards building APIs and supporting machinery that can be stable and supported in the long term.

Issue 3818

Functionality deprecated in GROMACS 2019

Generation of virtual sites to replace aromatic rings in standard residues

These are thought to produce artefacts under some circumstances (unpublished results), were never well tested, are not widely used, and we need to simplify pdb2gmx.

Issue 3254

Benchmarking options only available with gmx benchmark

Options such as -confout, -resethway, -resetstep are not intended for use by regular mdrun users, so making them only available with a dedicated tool is more clear. Also, this permits us to customize defaults for e.g. writing files at the end of a simulation part in ways that suit the respective mdrun and benchmark use cases, so -confout will no longer be required.

Issue 3255

gmx mdrun -nsteps

The number of simulation steps described by the .tpr file can be changed with gmx convert-tpr, or altered in .mdp file before the call to gmx grompp. The convenience of this mdrun option was outweighed by the doubtful quality of its implementation, no clear record in the log file, and lack of maintenance.

Issue 3256