Calculating forces in reftraj runs

[Ondrej Marsalek]

If someone could confirm that this makes sense, I'd try to submit a patch.

Thanks,
Ondrej

On Thu, Feb 18, 2016 at 6:53 PM, Ondrej Marsalek
<ondrej.... at gmail.com> wrote:
> Dear CP2K developers,
>
> I am doing reftraj runs where I am interested in some electronic
> properties, but not in the forces on atoms. It seem that these are
> always calculated, though, with no setting in the input file - the one
> that is available is energy+forces or nothing. I have tried disabling
> forces in `force_env_methods.F` (just changing `calculate_forces`)
> and, as an example, with a hybrid functional I got times per step go
> down from ~135 s to ~115 s. While this is not a deal breaker by any
> means, it would be nice to have a settings for reftraj, where you can
> enable the calculation of the forces separately. My guess would be
> that on line 1674 of `motion/integrator.F` the call to
> `force_env_calc_energy_force` should get `calc_force` passed to it,
> which would be read from a new setting in the REFTRAJ section.
>
> Thank you for considering this,
> Ondrej