[lammps-users] non-gaussian parameter

I worked supercooled liquids in Gallium, I`m tryng to calculation
non-Gaussian parameter use formule

          3 < r(t)**4 >
    NGP= ----------------- - 1
          5 < r(t)**2 >**2

but in doing the calculation gives wrong results (negative values) all
times, the result must always be positive, in short time near zero and
long time near zero. NGP testing in liquid state is near zero all time but
gives wrong results.

I`was calculated msd and mqd from a single trajectory by only performing a
time average this valis for calculation NGP because msd is calculated of
single trajectory but mqd is equal.

You can send information how calculation NGP of dates simulation.

I hope your help
thank you very much

I don't understand your question and you don't
explain what you are doing. What is the msq?

If you are writing a complex formula in your
script and it isn't producing the answer you expect,
then I suggest you "debug" it, by checking each
piece of the formula and seeing that it gives
the answers you expect.