[gmx-users] g_dipoles, average not the same as from g_analyze

Dmitri Dubov ddubov at ngs.ru
Thu Jun 10 05:48:49 CEST 2010

Dear Emanuel,

Please, check 
and Berk reply.

I did never use -av (-a ?) option, maybe there is similar bug in average.xvg. 
Anyway last column of Mtot.xvg gives really correct norm of M_tot vector!


> Dear gromacs users,

> Sorry but my last email was not correct. 
> I have following question:

> With the use of the g_dipoles tool I have analysed the average
> dipole moment using following command:

> g_dipoles -f *.trr -s *.tpr -n *.ndx -av average.xvg 

> I think the option -av calculates the average of the dipole moment of the system I have chosen.

> Following output is given:

> x1 = time (ps)
> y1 = aver1
> y2 = aver2**2
> y3 = aver1 - aver2**2
> ...

> I have taken the root of aver2 (y2^(1/2)) to get  and plotted that against x1.

> Mtot.xvg corresponds to the following quantities:

> x1 = time (ps)

> y1 = M_x
> y2 = M_y
> y3 = M_z
> y4 = M_tot

> I plotted M_tot against time and calculated the average by using g_analyze.
> Now I have following problem:
> My average value from g_analyze is not equal to the value of  which I received from g_dipoles.
> The difference between the two values is at about 20 Debye. 
> Could you tell me the reason why there exists a difference?
> Does g_dipoles calculate the average in another way than g_analyze?

> Thank you for your kind answer in advance.

> Best regards,

> Emanuel Peter
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://maillist.sys.kth.se/pipermail/gromacs.org_gmx-users/attachments/20100610/a7e39913/attachment.html>

More information about the gromacs.org_gmx-users mailing list