[gmx-developers] WARNING: Found more than 12 triclinic correction vectors, ignoring some.

[Berk Hess]

Tsjerk Wassenaar wrote:

> Hi,
>
> I met the following warning when running genion:
>
> WARNING: Found more than 12 triclinic correction vectors, ignoring some.
>  There is probably something wrong with your box.
>         Box (3x3):
>            Box[    0]={ 6.79189e+00,  0.00000e+00,  0.00000e+00}
>            Box[    1]={-2.06669e+00,  5.07661e+00,  0.00000e+00}
>            Box[    2]={ 1.33585e+00, -1.79879e+00,  4.65595e+00}
>
> This is strange, since the box fully complies with the gromacs rules
> (it was transformed to comply with gromacs rules). I tracked the
> message to low_set_pbc in pbc.c, but couldn't figure out the rationale
> behind the warning. Maybe one of the developers could shed some light
> on the matter? To my opinion, gromacs shouldn't complain/warn about a
> box meeting its standards. Also, editconf/genbox did not complain.
>
Your box does not really comply with the Gromacs requirements.
(-box[1][x]+box[2][x])/box[0][x] = 0.50097
This is more than 0.5, so there are more than 12 correction vectors.

There is a small margin in correcting the box vectors in Gromacs,
so we do not continuously change them because of rounding issues.

But the margin was always 0.5001. In CVS it is currently 0.501.
So are you using CVS code?

Berk.