[SciPy-user] neighbourhood of randomly scattered points [Was: choose at random all elements in a array...]

Matthieu Brucher matthieu.brucher@gmail....
Tue Aug 28 02:36:23 CDT 2007

```Hi,

Considering your window and your points, it doesn't surprise me much. What
do you want exactly as a result ?

Matthieu

2007/8/28, fred <fredmfp@gmail.com>:
>
> fred a écrit :
> > Hi all,
> >
> > I would like to show how I use this,
> > with a result, which seems to be strange to me.
> >
> > I have a float array, with dimensions of 501x501.
> > The values in this array are the scalar values at the point (x=i*dx,
> > y=j*dy,)
> > with i=0..500 & j=0..500.
> >
> > I flatten this array and get 15000 random (with random.permuation
> > method) values from this array
> > and thus get 15000 points.
> > Then I want to find out the number of neighboors from each of theses
> > points,
> > in a neighboorhood of (2*20+1)x(2*20+1).
> >
> > Thus, I get an array with coords and the number of neighboors.
> > x0 y0 nb0
> > x1 y1 nb1
> > ...
> >
> > I display the result with mayavi2, and get the following snapshot:
> > http://fredantispam.free.fr/snapshot.png
> >
> > Structures clearly appear.
> > (I don't consider side effects, of course).
> >
> > What could be the meaning of this ?
> > If it was "totally random", should I not get no structure at all,
> > something like a white noise ?
> >
> > What am I doing wrong ?
> >
> > How can I get a totally random scatter points ?
> No one can help me on this issue ?
>
> TIA.
>
> Cheers,
>
> --
> http://scipy.org/FredericPetit
>
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