Combination of distances between multiple points

6 views (last 30 days)
Mirza Ahmed on 29 Jul 2021
Commented: Mirza Ahmed on 3 Aug 2021
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!

Rik on 29 Jul 2021
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 on 3 Aug 2021
Thanks, man