Combination of distances between multiple points

I have a number of circles, where I can define the number at the beginning, i = number of circle. I have to calculate every minimum distance between every circle. That means the equation can be written as:

dist = (x1-x2)^2 + (y1-y2)^2 - (r1+r2)

Let's say the number of circle is chosen 6, so the number of combination of distances come as 15.

To define the variables first, I have declared the matrices of radius, x coordiantes and y coordinates. Now, from this point onwards, I need help to write the basic and generalized code to find the combination.

Thanks!

Answer 1

[Rik]

You already have the generalized code. You just need to combine it with nchoosek:

x=1+10*rand(1,6);
y=1+10*rand(1,6);
r=rand(1,6);

combs=nchoosek(1:6,2);
c1=combs(:,1);c2=combs(:,2);
d=(x(c1)-x(c2)).^2 + (y(c1)-y(c2)).^2 - (r(c1)+r(c2));
combs(:,3)=d

combs = 15×3

1.0000 2.0000 7.9112 1.0000 3.0000 8.4890 1.0000 4.0000 8.4228 1.0000 5.0000 5.9644 1.0000 6.0000 21.6430 2.0000 3.0000 28.6815 2.0000 4.0000 34.0819 2.0000 5.0000 1.8794 2.0000 6.0000 11.5847 3.0000 4.0000 3.2875

%(circle 1, circle 2, distance)

[Mirza Ahmed]

Thanks, man