Minimization of even small molecules to convergence is problematic in GROMACS. I am finding that energy minimization not always succeeds, even for very simple molecules such as 2-octanol or pentoxypentane. This leads to problems when you want to do a normal mode analysis based on that structure. It would be useful to have a minimizer that **does** go all the way to zero force (steepest descents doesn’t do it either). To reproduce the problem, unpack the archive, then run gmx\_d grompp gmx\_d mdrun It will finish with: “Energy minimization has stopped, but the forces have not converged to the requested precision Fmax < 0.001” *(from redmine: issue id 2641, created on 2018-09-11 by dspoel, closed on 2019-04-05)* * Relations: * relates #1593 * Changesets: * Revision 23c57b58a9a6ad7d12aee776090139282a5eece9 on 2019-04-05T08:15:28Z: ``` Fixes bug in l-bfgs. l-bfgs should now work excatly as it was in 4.6.5, up-to some numerical precision in forces and energies. Fixes #2641 Change-Id: I11a85a4241cc933fef94e2095dd8c3cbbb28b01b ``` * Uploads: * [2-octanol.zip](/uploads/76f15c57ab63bd3aaee378e953a3e335/2-octanol.zip) * [wat-2-tip3p.zip](/uploads/55b6b417feca46ba91c55d1b205dbfe5/wat-2-tip3p.zip) * [minimize.cpp](/uploads/e7c13ccb892da24229ec9cf5642bd293/minimize.cpp) * [minimize_new.cpp](/uploads/9cb840257834fd9b3ec9060e65069b2d/minimize_new.cpp)