26?

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Jonathan.
"Trevor Quayle" <Tin### [at] hotmailcom> ha scritto nel messaggio
news:3bcdc957$1@news.povray.org...
> Actually you should check the 26 cubes immediately surrounding the cube in
> question as well, otherwise particles at the very edge of one cube
wouldn't
> be influenced by particles at the very edge of the next cube
>
> -tgq
>
>
> "Chris Jeppesen" <chr### [at] digiquillcom> wrote in message
> news:3bcdc15c$1@news.povray.org...
> > Well, the basic alogrithm is to find the closest neighboring particle,
and
> > if it is within a certain distance, generate a force towards this
nearest
> > neighbor. The slow O(N^2) part is finding the nearest particle.
> >
> > What if you chopped up the space into cubes, and only looked for a
nearest
> > neighbor in the same cube? I assume that somewhere deep down in your
> > simulation is a 1-dimensional array representing the particles.
> >
> > Suppose you divided the space into 10x10x10 cubes, and had a
4-dimensional
> > array Neighbors[10][10][10][N_PARTICLES]. When the physics loop starts,
> the
> > array is cleared. When each particle position is updated, calculate
which
> > cube it belongs in, say <4,5,6> and write that into Neighbors[4][5][6].
> Now
> > when it comes time to calculate, for each particle only check for its
> > nearest neighbor in the same neighbor cube. This could reduce time to
> > O(1000*(N/1000)^2).
> >
>
>
>

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