Re: generating symmetric array from function?

["Liam E. Gumley" <Liam.Gumley(at)ssec.wisc.edu>]

Nick Bower wrote:
> 
> how do I generate symmetric 2D array from a function of one variable?
> 
> eg. say i want the sinc function in 3 dimensions - how do i generate
> this symmetrically in both x and y dimensions?
> 
> presumably, the last step would be a shift by N/2 in both x and y
> directions to move the origin to the centre of the array, but i'm just
> not sure what comes before this and how to do it without nested loops
> over the array elements.

v = findgen(41) * 0.5 - 10.0
x = rebin(v, 41, 41, /sample)
y = rebin(reform(v, 1, 41), 41, 41, /sample)
r = sqrt(x^2 + y^2) + 1.0e-6
z = sin(r) / r
surface, z, x, y

Cheers,
Liam.
http://cimss.ssec.wisc.edu/~gumley