nlms output graphs not coming correctly. what is the problem in the code ?? given inputs a). 20 b). 40 c). -20

d = .5; 
N=6;
thetaS = input('   What is the desired users AOA (in degrees)?   ');
thetaI = input('   What is the 1st interferers AOA(in degrees)?   ');
thetaIs = input('   What is the 2nd interferers AOA(in degrees)?   ');

T=1E-3;
t=(1:100)*T/100;
it=1:100;
S=cos(2*pi*t/T);
thetaS = thetaS*pi/180;                  % desired user AOA
I = randn(1,100); 
thetaI = thetaI*pi/180;  % interferer AOA
Is = randn(1,100); 
thetaIs = thetaIs*pi/180;  % interferer AOA
a = 0.001;

vS = []; vI = []; vIs = [];
i=1:N;
vS=exp(1j*(i-1)*2*pi*d*sin(thetaS)).';
vI=exp(1j*(i-1)*2*pi*d*sin(thetaI)).';
vIs=exp(1j*(i-1)*2*pi*d*sin(thetaIs)).';

w = zeros(N,1);     snr = 10;  % signal to noise ratio
 X=(vS+vI+vIs);
Rx=X*X';
mu=1/(4*real(trace(Rx)))

wi=zeros(N,max(it));
for n = 1:length(S)
    x = S(n)*vS + I(n)*vI + Is(n)*vIs;
    %y = w*x.';
    y=w'*x;

      e = conj(S(n)) - y;      esave(n) = abs(e)^2;
      w = w + mu/(0.001+x'*x) * x.* conj(e) ;
      wi(:,n)=w;
      yy(n)=y;
  end
  w = (w./w(1));    % normalize results to first weight

theta = -pi/2:.01:pi/2;
AF_3 = zeros(1,length(theta));

for i = 1:N
    AF_3 = AF_3 + w(i)'.*exp(1j*(i-1)*2*pi*d*sin(theta));
end

figure;
plot(it,S,'k',it,yy,'k--')
xlabel('No. of Iterations')
ylabel('Signals')
legend('Desired signal','Array output')
title('NLMS');

disp('%------------------------------------------------------------------------%')
disp(' ')
disp(['   The weights for the N = ',num2str(N),' ULA are:'])
disp(' ')
for m = 1:length(w)
    disp(['   w',num2str(m),' = ',num2str(w(m))])
end
disp(' ')

figure;plot(it,abs(wi(1,:)),'kx',it,abs(wi(2,:)),'ko',it,abs(wi(3,:)),'ks',it,abs(wi(4,:)),'k+',it,abs(wi(5,:)),'kd','markersize',2)
xlabel('Iteration no.')
ylabel('|weights|')
title('NLMS');

figure;
plot(it,esave,'k')
xlabel('Iteration no.')
ylabel('Mean square error')
title('NLMS');

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