Analytical intersection area between two circles

Compute the overlap area between 2 circles defined in an array Computation is vectorized, and intersection area are computed an analytical way.

Input: Circles data presented in an array G of three columns.
G contains parameters of the n circles
. G(1:n,1) - x-coordinate of the center of circles,
. G(1:n,2) - y-coordinate of the center of circles,
. G(1:n,3) - radii of the circles
Each row of the array contains the information for one circle.

Input can also be provided in three different vectors. These vectors can be row or column vectors. The 1st one corresponds to x-coordinate of the center of circles, the 2nd one to the y-cooridnate and the 3rd one to the radii of the circles.

Output: Square matrix M(n,n) containing intersection areas between circles
M(i,j) contains the intersection area between circles i & j
By definition, M(i,i) corresponds to the area of circle i.