[CP2K:1938] Negative values of distance point plane

Teodoro Laino teodor... at gmail.com
Wed Apr 1 17:18:51 UTC 2009

Dear Daniel,

the colvar distance_point_plane has indeed a sign (which is of course 
arbitrary but the convention
is kept identical through all the runs).

It's like the X-axis when the plane is represented by the Y-Z plane. In 
this case you have negative values
as well as positive ones (depending whether you are on the right or on 
the left of the plane).
The FES is then reconstructed appropriately (keeping into account that 
there is a sign).


Daniel_M wrote:
> Hello all,
> I am doing a metadynamics run with two CV's, the first one is a
> distance difference, and the second one is a distance form one atom to
> the plane defined by another three atoms (distance_point_plane), and
> in the restart file I get this:
>             -4.2713988616046992E+00    1.7692731063313687E+00
>             -4.2415320702304804E+00    1.6823099667946908E+00
>             -4.1197722933904597E+00    1.6400825985199678E+00
>             -4.0211331086844284E+00   -1.7636635945478967E+00
>             -4.0887529234851119E+00   -1.8119253111270353E+00
>             -4.3118373674780779E+00   -1.8777540223261953E+00
>             -4.5038606867087800E+00   -1.9127672598968923E+00
>             -4.5467464488708362E+00   -1.8940504927990562E+00
>             -4.4478669666377524E+00   -1.8071942971411046E+00
>             -4.2782329931276726E+00   -1.6799394839899713E+00
>             -4.0599453872710356E+00   -1.5353354404292809E+00
>             -3.7256739864976223E+00   -1.4408969228377622E+00
>             -3.2889301466304106E+00    1.5168333233130824E+00
>             -3.3312107263224515E+00    1.6300531470526305E+00
>             -3.9632834279171361E+00    1.8350661975684184E+00
>             -4.7936175752581018E+00    2.0804316415464172E+00
>             -5.3922491308119431E+00    2.2976355912785600E+00
>             -5.6080480550074885E+00    2.4572528448822148E+00
>             -5.4284540537686894E+00    2.5602508049566670E+00
>             -4.9798068411401930E+00    2.6085576679914477E+00
>             -4.3567044485888404E+00    2.5994868107989220E+00
>             -3.7234913325899757E+00   -2.3902310570173584E+00
>             -3.3239883518412294E+00    2.5195888354088920E+00
> As you can see, in the second column the distance_point_plane takes
> positives and negatives values with no apparent reason (and I have
> checked the trajectory and the system behaviour is correct), so I
> suposse that "internally" cp2k is treating these values as positive
> values, but I don't know if this may be indicative of some more
> important bug. And, in any case, I think that this will lead to
> serious problems when reconstructing the FES if somebody tries to do
> that without taking a look at the restart file previously.
> Regards,
> Daniel
> ** I have been looking at the previous discussions and haven't found
> anything about this. My apologies if this has been already discussed.
> >

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