is this code is right? this code is for trilateration it shows error.

This code is shows error at line 22 and 29

warning is : matrix is singular to working precision.

is this code is right if not please give suggetions..

function [ x, y ] = two_tri(x1, x2, x3, y1, y2, y3, d1, d2, d3)

%2-D trilateration function

% Inputs: Readers 1-3 (x,y) and Distances to Tag

%

% x_n1 = (d1^2 - d2^2)-(x1^2 - x2^2)-(y1^2 - y2^2)*2*(y3 - y1)

% x_n2 = 2*(y2 - y1)*(d1^2 - d3^2) - (x1^2 - x3^2) - (y1^2 - y3^2)

% x_d = 2*(x2 - x1)*2*(y3 - y1) - 2*(y2 - y1)*2*(x3-x1)

% x = (x_n1 - x_n2)/x_d

% y = 2;

%

x_n11 = (d1^2 - d2^2) - (x1^2 - x2^2) - (y1^2 - y2^2);

x_n21 = (d1^2 - d3^2) - (x1^2 - x3^2) - (y1^2 - y3^2);

x_n12 = 2*(y2-y1);

x_n22 = 2*(y3-y1);

d11 = 2*(x2-x1);

d21 = 2*(x3-x1);

d12 = 2*(y2-y1);

d22 = 2*(y3-y1);

x_n = [x_n11, x_n12; x_n21, x_n22];

d = [d11, d12; d21, d22];

x = x_n/d;

x = det(x);

y_n11 = d11;

y_n21 = d21;

y_n12 = x_n11;

y_n22 = x_n21;

y_n = [y_n11, y_n12; y_n21, y_n22];

y = y_n/d;

y = det(y);

x11=[x1 x2 x3 x];

y11=[y1 y2 y3 y];

scatter(x11,y11);

disp(x11);

disp(y11);

end

Answer 1

[Walter Roberson]

You never use the output of your det() calls, so you should get rid of them.

[Darshan Patel]

i am new to matlab can you elaborate?

[Darshan Patel]

it shows the error in

x_n11 = (d1^2 - d2^2) - (x1^2 - x2^2) - (y1^2 - y2^2);

that d1 is undefine

[Walter Roberson]

You cannot run the code just by pressing an F key or clicking on the Run button. You need to go to the command line and use the routine in command form, passing in the data you need. For example,

x = rand(1,3); y = rand(1,3); d = rand(1,3);
[X, Y] = two_tri(x(1), x(2), x(3), y(1), y(2), y(3), d(1), d(2), d(3))