New and improved features#

Density-guided simulations#

Users can now apply additional forces from three dimensional reference densities. These forces can be used to “fit” atoms into the densities by increasing the similarity of a simulated density to the reference density.

Multiple protocols are available for how to calculate simulated densities as well as how the similarity between a reference and a simulated density is evaluated.

Virtual site on the line through two atoms at fixed distance#

This is use useful for e.g. halogens in the CHARMM force field.

Issue 2451

gmxapi Python support#

Data flow driven simulation and analysis from Python is now available in a default GROMACS installation when users install the gmxapi Python package. See gmxapi Python package.

New modular simulator#

A new approach for how to combine individual calculation steps during a single simulation step is introduced, with focus on extensibility and modularization. This simulator is the default now for simulations using velocity-verlet in NVE, NVT (v-rescale thermostat only), NPT (v-rescale thermostat and Parrinello-Rahman barostat only), or NPH (Parrinello-Rahman barostat only), with or without free energy perturbation.