Is there a solution to use "circcirc" with continuous variable as radius?

Hello, I am trying to implement trilateration algorithm and I am using "circcirc" command to find intersections of the circles.

My problem is: I need to find intersections of circles, which changes their radius every step but they have the same centers. Is it possible without re-writing the command or with another command?

This is my code:

 Center1=[0.75,5];
 Center2=[6.98,4.31];
 Center3=[3.46,1.48];
 radii1=[1; 3; 4];
 radii2=[2.5; 3; 2.3];
 radii3=[3; 1; 5];
 [x_intersection1_2,y_intersection1_2] = circcirc(Center1(:,1),Center1(:,2),radii1,Center2(:,1),Center2(:,2),radii2);
 [x_intersection1_3,y_intersection1_3] = circcirc(Center1(:,1),Center1(:,2),radii1,Center3(:,1),Center3(:,2),radii3);
 [x_intersection2_3,y_intersection2_3] = circcirc(Center2(:,1),Center2(:,2),radii2,Center3(:,1),Center3(:,2),radii3);

Answer 1

[Pawel Ladosz]

Hi Miro,

You may want to use for or while loops. Please find description here. The exact code would vary depending on which radius you want to change at what time.

[Miro Mitev]

Hello Pawel,

I want to change all the radii at each next iteration. Now I tried this, but it gives me mistake:

Center1=[0.75,5];
Center2=[6.98,4.31];
Center3=[3.46,1.48];
radii1=[1, 3, 4];
radii2=[2.5, 3, 2.3];
radii3=[3, 1, 5];

x1_2=zeros(1,4);
y1_2=zeros(1,4);
x1_3=zeros(1,4);
y1_3=zeros(1,4);
x2_3=zeros(1,4);
y2_3=zeros(1,4);

for n = 2:3
    [x1_2(n),y1_2(n)] = circcirc(Center1(:,1),Center1(:,2),radii1(n),Center2(:,1),Center2(:,2),radii2(n));
    [x1_3(n),y1_3(n)] = circcirc(Center1(:,1),Center1(:,2),radii1(n),Center3(:,1),Center3(:,2),radii3(n));
    [x2_3(n),y2_3(n)] = circcirc(Center2(:,1),Center2(:,2),radii2(n),Center3(:,1),Center3(:,2),radii3(n));
end

[Pawel Ladosz]

Hi Miro,

I am not sure why you getting this error. As a solution I propose assigning the output of function to temporary variables a,b,c and then assigning it to actual variables, please find code below.

Center1=[0.75,5];
Center2=[6.98,4.31];
Center3=[3.46,1.48];
radii1=[1, 3, 4];
radii2=[2.5, 3, 2.3];
radii3=[3, 1, 5];
x1_2=zeros(1,4);
y1_2=zeros(1,4);
x1_3=zeros(1,4);
y1_3=zeros(1,4);
x2_3=zeros(1,4);
y2_3=zeros(1,4);
for n = 2:3
    a = circcirc(Center1(:,1),Center1(:,2),radii1(n),Center2(:,1),Center2(:,2),radii2(n));
    x1_2(n)=a(1);
    y1_2(n)=a(2);
    b = circcirc(Center1(:,1),Center1(:,2),radii1(n),Center3(:,1),Center3(:,2),radii3(n));
    x1_3(n)=b(1);
    y1_3(n)=b(2);
    c = circcirc(Center2(:,1),Center2(:,2),radii2(n),Center3(:,1),Center3(:,2),radii3(n));
    x2_3(n)=c(1);
    y2_3(n)=c(2);
end

[Miro Mitev]

Thanks a lot for your help. That is perfect! :)

[Miro Mitev]

No actually it is not, now i see. It gives me just 1 coordinate for X and 1 for Y. But the circles have 2 intersections. Still something missing :/

[Pawel Ladosz]

yes, I made a mistake regarding the number of outputs of function. x and y are now 2x3 matrix where each row is a different coordinate and each column different radius. Let me know whether it works now.

Center1=[0.75,5];
Center2=[6.98,4.31];
Center3=[3.46,1.48];
radii1=[1, 3, 4];
radii2=[2.5, 3, 2.3];
radii3=[3, 1, 5];

%initialize them as 2 by 3 rather than 1 by 4
 x1_2=zeros(2,3);
 y1_2=zeros(2,3);
 x1_3=zeros(2,3);
 y1_3=zeros(2,3);
 x2_3=zeros(2,3);
 y2_3=zeros(2,3);
for n = 1:3
    [x1_2(:,n),y1_2(:,n)] = circcirc(Center1(:,1),Center1(:,2),radii1(n),Center2(:,1),Center2(:,2),radii2(n));

      [x1_3(:,n),y1_3(:,n)] = circcirc(Center1(:,1),Center1(:,2),radii1(n),Center3(:,1),Center3(:,2),radii3(n));

      [x2_3(:,n),y2_3(:,n)] = circcirc(Center2(:,1),Center2(:,2),radii2(n),Center3(:,1),Center3(:,2),radii3(n));
  end

[Miro Mitev]

Thanks a lot. Yes it is working this time perfectly.

I have fixed it by the way bellow but your approach is much more simple.

[c,c1] = circcirc(Center2(:,1),Center2(:,2),radii2(n),Center3(:,1),Center3(:,2),radii3(n));
    x2_3(1,n)=c(1);
    y2_3(1,n)=c1(1);
    x2_3(2,n)=c(2);
    y2_3(2,n)=c1(2);