How do we make sure that the magnitude response of W(e^jw) is being calculated at the same set of frequencies in W’ by the command 'freqz' at every iteration?

For the equation in the attached file, FB(e^jw) is the Fourier transform of the feedback filter fb and W(e^jw) is the Fourier transform of adaptive filter w.

%%Feedback Path declared
fb=fir1(50,[0.2500 0.8750]); % feedback coefficients
[a1,b1]=freqz(fb,1,80000);   % Frequency response of feedback path fb

%%For loop for traversing iterations 
for n = 1:ITER  %%ITER = length (input signal)

     [a2,b2]=freqz(w,1,80000); %Frequency response of adaptive filter w

     % code for computing misalignment
     num1=abs(a1-a2).^2;
     num2=cumtrapz(b1,num1);%numerator of misalignment eqn mentioned above

     den1=abs(a1).^2;
     den2=cumtrapz(b1,den1);%denominator of misalignment eqn mentioned above

     MSL(n)=mean(num2./den2); % vector MSL contains misalignment values for
      % every iteration

end

The MATLAB command freqz calculates the frequency response of a digital filter with zeros vector B and poles vector A as: [H, W’] = freqz (B, A, N) returns the N-point complex frequency response vector H and the N-point frequency vector W’ in radians/sample of the filter. When traversing iterations n = 1: length (input signal), FB(e^jw) remains same for every iteration because fb is defined as a fixed FIR filter. However, W(e^jw) changes for every iteration, because the adaptive filter w changes after every iteration. In order to plot the Misalignment curve, i must make sure that for every iteration, W(e^jw) is calculated at the same frequencies in frequency vector W’. Question :How do we make sure that the magnitude response of W(e^jw) is being calculated at the same set of frequencies in W’ at every iteration?