Intersection of Fibers...

I have written a code regarding checking for intersection of fibers within the fibers...but there is some errors in it...I am unable to fix it. Kindly help

function FibList=Generatefibers_trial(x,y,z,L,N)

for i=1:1:N
    while 1
        x1=min(x)+(max(x)-min(x))*rand(1); 
        y1=min(y)+(max(y)-min(y))*rand(1);
        z1=min(z)+(max(z)-min(z))*rand(1);
        theta=2*pi*rand(1);  %angle 
        gamma=2*pi*rand(1); %angle
        phi=2*pi*rand(1); %angle
        Dr=[cos(gamma)*cos(phi)-cos(theta)*sin(gamma)*sin(phi)  sin(gamma)*cos(phi)+cos(theta)*cos(gamma)*sin(phi) sin(theta)*sin(phi)  ...
            ; -cos(gamma)*sin(phi)-cos(theta)*sin(gamma)*cos(phi) -sin(gamma)*sin(phi)+cos(theta)*cos(gamma)*cos(phi) sin(theta)*cos(phi)  ...
            ;                  sin(theta)*sin(gamma)                         -sin(theta)*cos(gamma)                         cos(theta)     ];
        c2=[x1 y1 z1]'+Dr*[L 0 0]';
        x2=c2(1);
        y2=c2(2);
        z2=c2(3);
        if x2<=x(2) && x2>=x(1) && y2<=y(2) && y2>=y(1) && z2<=z(2) && z2>=z(1)  
            break;
        end     
    end
    % Coordinates
    Fiber(i,1)=x1;
    Fiber(i,2)=y1;
    Fiber(i,3)=z1;
    Fiber(i,4)=x2;
    Fiber(i,5)=y2;
    Fiber(i,6)=z2;
    
    % Matrix representation of the coordinates generated. 
    if i==1
        FibList=[Fiber(i,1) Fiber(i,2) Fiber(i,3) Fiber(i,4) Fiber(i,5) Fiber(i,6)];
    else
        NewFib=[Fiber(i,1) Fiber(i,2) Fiber(i,3) Fiber(i,4) Fiber(i,5) Fiber(i,6)];
        j=1;
        count=0;
        while j<i
            syms s t
            eqn1=s*(FibList(j,4)-FibList(j,1))-t*(NewFib(1,4)-NewFib(1,1)) == NewFib(1,1)-FibList(j,1); % I am getting error in this line.
            eqn2=s*(FibList(j,5)-FibList(j,2))-t*(NewFib(1,5)-NewFib(1,2)) == NewFib(1,2)-FibList(j,2);
            [A, B] = equationsToMatrix([eqn1, eqn2],[s,t]);
            X=linsolve(A,B);
            s=vpa(X(1,1));
            t=vpa(X(2,1));
            %Criteria for checking intersection of 2 line segments in 3D.
            if (s>=0 && s<=1)&&(t>=0 && t<=1)&&((s*(FibList(j,6)-FibList(j,3))-t*(NewFib(1,6)-NewFib(1,3))== NewFib(1,3)-FibList(j,3)))
                count=count+1;
            end
            j = j+1;
        end
        
        %fprintf('the value of s is %f\n the value of t is %f ',X)
        if count==i-1
            FibList = [FibList; NewFib];
        else
            FibList = [FibList];
            i = i-1; % this will repeat the loop for the same i value, if the intersection criteria...
            %is not fulfilled.
        end
    end
end
end

Error messgae:

Index exceeds matrix dimensions.

Error in Generatefibers_trial (line 39)

eqn1=s*(FibList(j,4)-FibList(j,1))-t*(NewFib(1,4)-NewFib(1,1)) == NewFib(1,1)-FibList(j,1);

[Jan]

Post your code and copies of the complete error messaged. Otherwise it is impossible to help you.

[Sushant]

Kindly help me in fixing the error.

[Jan]

Simplify

FibList=[Fiber(i,1) Fiber(i,2) Fiber(i,3) Fiber(i,4) Fiber(i,5) Fiber(i,6)];

to

FibList = Fiber(i, 1:6);

You can use the debugger to stop the execution, when the error occurs. Type in the command window:

dbstop if error

Now run the code again and check the values of the indices, when the error occurs.