Why I'm getting this error( Array indices must be positive integers or logical values)?

M=3
W = [0,0,0]
for n = 0:2000
    x = cos(0.03 * pi * n)
    stem(n,x) 
    hold on; % hold the plot
end
b= [1 -2 4];
freqz (b,1)
for n = 0:2000
    d=conv(x,b)
    y=transpose(W)*x
    e=d-y;
    w(n+1) = w(n)+(2*0.01*e*[x(n),x(n+1),x(n+2)])%  µ=0.01;
end

[KSSV]

Srat the loop indexing from 1.

[Jan]

Which lines is failing? Please post the complete error message, which would clarify this detail.

[Sliman Izz]

Array indices must be positive integers or logical values.

Error in untitled3 (line 16)

w(n+1) = w(n)+(2*0.01*e*[x(0),x(1),x(2)])% µ=0.01;

Answer 1

[Jan]

When I run your code, it stops with the error, the w is undefined in the line:

w(n+1) = w(n)+(2*0.01*e*[x(n),x(n+1),x(n+2)])%  µ=0.01;

But even if w exists in the real code, w(0) is not a valid index in the first iteration, because in Matlab indices start at 1.

x(n) will fail also for n=0. But for n=2 there will be an error again, because the first loop creates a scalar x only.

Another bold guess is, that you have redefined a function as an array, e.g. "cos" or "stem".