function disc,n
;+
;s=disc(n) is an nxn array that contains the distance of each point
;from the center.
;
;USAGE:
;s=disc(7)
;print,s
;      4.24264      3.60555      3.16228      3.00000      3.16228      3.60555      4.24264
;      3.60555      2.82843      2.23607      2.00000      2.23607      2.82843      3.60555
;      3.16228      2.23607      1.41421      1.00000      1.41421      2.23607      3.16228
;      3.00000      2.00000      1.00000     0.000000      1.00000      2.00000      3.00000
;      3.16228      2.23607      1.41421      1.00000      1.41421      2.23607      3.16228
;      3.60555      2.82843      2.23607      2.00000      2.23607      2.82843      3.60555
;      4.24264      3.60555      3.16228      3.00000      3.16228      3.60555      4.24264
;
;H. Rhody
;Sept. 7, 2005
;-
x=(findgen(n)-(n-1)/2.)#replicate(1,n)
y=(findgen(n)-(n-1)/2.)##replicate(1,n)
return,sqrt(x^2+y^2)
end