Re: [CHANGESET] Re: Help with griddata3

[António Santos]

> António Santos wrote:
> > Hi,
> >
> > It solved the problem but the function seems to not return valid data,
> > only NaNs.
> > I tried this:
> >
> > rand('state',0);
> > x = 2*rand(5,1)-1;
> > y = 2*rand(5,1)-1;
> > z = 2*rand(5,1)-1;
> > v = x.^2 + y.^2 + z.^2;
> > d = -0.8:0.05:0.8;
> > [xi,yi,zi] = meshgrid(d,d,d);
> > w = griddata3(x,y,z,v,xi,yi,zi)
> >
> > w only contains NaNs...Is anyone experiencing this problem too? Or am
> > I doing something wrong?
> >
> > Thanks,
> Yes, you are doing something wrong.. The Delaunay Tesselation in 3D
> requires 4 points per simplex. Therefore with 5 per points of data you
> have only two Dealaunay simplices defined.. In 3D these are tetrahedra,
> and with random data they are going to be often long and thin, and in
> the case above all of the data falls outside the tetrahedra and there is
> therefore no data to interpolate with. Replace 5 with 1000 above and it
> should work.

Indeed! I need to learn a bit more about this. Thanks a lot!

António Santos