# [gmx-users] average radius of gyration

Mark Abraham Mark.Abraham at anu.edu.au
Mon Nov 24 10:44:03 CET 2008

```Q. Y. HUAN wrote:
> Dear Mark,
>
> I am a bit confuse with yr advice,
> after i did g_gyrate, I examine the gyration.xvg and I get this( I only show part of the data):
>
>
> @    title "Radius of gyration"
> @    xaxis  label "Time (ps)"
> @    yaxis  label "Rg (nm)"
> @TYPE xy
> @ view 0.15, 0.15, 0.75, 0.85
> @ legend on
> @ legend box on
> @ legend loctype view
> @ legend 0.78, 0.8
> @ legend length 2
> @ s0 legend "Rg"
> @ s1 legend "RgX"
> @ s2 legend "RgY"
> @ s3 legend "RgZ"
>          0    0.101214   0.0862465   0.0765928   0.0758378
>         10     0.10097   0.0852172   0.0766285   0.0764949
>         20    0.101094   0.0841315   0.0759198   0.0780227
>         30    0.101178   0.0845673   0.0760734   0.0780282
>         40    0.101101   0.0855135   0.0761306   0.0765843
>         50    0.102186    0.086539   0.0774698    0.077009
>         60    0.102582   0.0867398   0.0774364   0.0776702
>         70    0.103084   0.0862637   0.0772064   0.0798831
>         80     0.10225   0.0851082   0.0779015   0.0786001
>         90    0.101688   0.0866644   0.0763416   0.0771902
>        100    0.101904   0.0851727   0.0768526   0.0786537
>
>
>
> and the g_analyze for thr gyration.xvg is as follow:
>
>
>
> Read 4 sets of 201 points, dt = 10
>
>                                       std. dev.    relative deviation of
>                        standard       ---------   cumulants from those of
> set      average       deviation      sqrt(n-1)   a Gaussian distribition
>                                                       cum. 3   cum. 4
> SS1   1.038435e-01   1.336665e-03   9.451647e-05       0.110   -0.213
> SS2   8.344679e-02   1.333312e-03   9.427939e-05      -0.028   -0.097
> SS3   8.096852e-02   1.840205e-03   1.301221e-04      -0.254   -0.037
> SS4            nan            nan            nan         nan      nan
>
>
> is it the average set SS1 (1.038435e-01) is the average of the 1st column for the data in gyration.xvg?

Yes.

Mark

```