MATLAB: How to save a value from an iteration of a for loop

for loopleast mean squarelsm

I am trying to save the value of en from this Least Mean Square algorithm after each loop, but my attempt at it does not seem to be working. How can I fix this?
close;
clear;
clc;
load sig.mat; % loads variables x and y
N = 5; % filter length
u = .01; % learning rate
h = zeros(1, N);
hold = zeros(1,500);
for n = 1:500
    if n-N < 1
        xn = [x(n:-1:1); zeros(N-n, 1)];
    else
        xn = x(n:-1:n-N+1);
    end
    en = y(n) - h*xn;
    hold = en;  %  Why is this not saving en after each iteration?
    h = h + (u*en*xn)';
end

Best Answer

First, rename the ‘hold’ variable to something that does not overshadow a MATLAB function. (I renamed it ‘env’.) Then, subscript it:
env = zeros(1,500);
. . .
en = y(n) - h*xn;
env(n) = en;
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