how to remove Vectors must be the same lengths error in following code?

Sir,i have implemented ESPRIT aLGORITHM FOR DIRECTION OF ARRIVAL estimation bt it is giving the above error in plot function.

    doas=[-30 -5 40]*pi/180;
    P=[1 1 1];
    N=10;
    K=1024;
    d=0.5;
    noise_var=1;
    r=length(doas);
    A=exp(-i*2*pi*d*(0:N-1)'*sin([doas(:).']));
    sig=round(rand(r,K)*2-1);
    noise=sqrt(noise_var/2)*(randn(N,K)+i*randn(N,K));
    X=A*diag(sqrt(P))*sig+noise;
    R=X*X'/K;
    [Q,D]=eig(R);
    [D,I]=sort(diag(D),1,'descend');
    Q=Q(:,I);
    Qs=Q(:,1:r);
    Qn=Q(:,r+1:N);
    angles=(-90:.1:90);
    phi=linsolve(Qs(1:N-1,:),Qs(2:N,:));
    for k=1:length(angles)
        ESPRIT_doas=asin(-angle(eig(phi))/(2*pi*d))*180/pi;
    end

    figure(1)
    plot(angles,abs(ESPRIT_doas))
    title('music spectrum')
    xlabel('angles in degrees')

Answer 1

[Matt J]

When I run your code, I get the following error

Error using plot
Vectors must be the same lengths.

Error in test (line 24)
    plot(angles,abs(ESPRIT_doas))

It makes perfect sense. When checking the lengths of "angles" and "ESPRIT_doas", one can easily see that they are not the same:

    K>> whos angles ESPRIT_doas
      Name             Size              Bytes  Class     Attributes

      ESPRIT_doas      3x1                  24  double              
      angles           1x1801            14408  double

There is nothing in your code that explains why the 2 should be the same length. You will have to explain that.

Answer 2

[Walter Roberson]

Your code

for k=1:length(angles)
      ESPRIT_doas=asin(-angle(eig(phi))/(2*pi*d))*180/pi;
end

is going to overwrite ESPRIT_doas each time through the loop. You need something closer to

for k=1:length(angles)
  ESPRIT_doas(:,k) = asin(-angle(eig(phi))/(2*pi*d))*180/pi;
end

However, notice that you do not change the right hand side of the expression according to k, so all of the values are going to be the same.