how can we find or display mean square error of Block LMS algorithm? The code is as follows:

%BLOCKLMS % Call: % [e,w]=blocklms(mu,M,u,Dalton); % % Input arguments: % mu = step size, dim 1x1 % M = filter length, dim 1x1 % u = input signal, dim Nx1 % d = desired signal, dim Nx1 % % Output arguments: % e = estimation error, dim Nx1 % w = final filter coefficients, dim Mx1 % % The length N is adjusted such that N/M is integer! % %initialization M=100; N=200; w=zeros(M,1); L=floor(N/M)*M; d=zeros(N,1); u=zeros(N,1); d=d(:); e=d; u=u(:); %no. of blocks Blocks=N/M; %Loop, BlockLMS for k=1:Blocks-1 %Set up input signal matrix, dim. MxM (cf. example 1, Haykin p. 448) umat=toeplitz(u(k*M:1:(k+1)*M-1),u(k*M:-1:(k-1)*M+1)); %Set up vector with desired signal dvec=d(k*M:1:(k+1)*M-1); %calculate output signal (Eq.10.5) yvec=umat.*w; %calculate error vector (Eq.10.8) evec=dvec-yvec; %log error e(k*M:1:(k+1)*M-1)=evec; %calculate gradient estimate (Eq.10.11) phi=umat.'*evec; %update filter coefficients (Eq.10.10) w=w+mu*phi; end