[Ifeffit] Cumulant expansion fittings
SCalvin at slc.edu
Wed Jan 21 21:30:28 CST 2009
You're right--3 dimensions ruins my symmetry argument. My mistake.
On the other hand, I still suspect that there exists a realistic case
where forcing the third cumulant to zero cause a much smaller increase
in chi-square than forcing the fourth cumulant to zero; e.g., a broad,
flat radial distribution function.
For those of you out there who are relative novices, this is an
entertaining and informative discussion, but I don't want to lose
track of the practical point:
It is very rare to find a system where the fourth cumulant is both
necessary and sufficient. Either the potentials are close enough to
harmonic that the fourth cumulant makes little difference, or they are
so far from harmonic that the fourth cumulant alone is not enough.
Sarah Lawrence College
On Jan 21, 2009, at 10:11 PM, Frenkel, Anatoly wrote:
> Thus, I am pretty much convinced, unless there is some mistake in my
> reasoning, that no case exists in 3D with a zero third cumulant.
More information about the Ifeffit