Moving Average using a for loop

Hi, How can I compute the moving average using a for loop and without using convolution (i.e conv()) or the filter function (i.e filter())?

[Jan]

If this is a homework question, and it does sound like it is one, please state this explicitly. Then show us, what you have tried so far and ask a specific question. We are not going to solve your homework.

[Jan]

Did you try anything to solve this problem by your own? What about asking your favorite internet search engine for Matlab code for a moving average? You'd find many many solutions in the FileExchange.

Answer 1

[Star Strider]

This seems to work:

data = rand(1,50);                          % Data
Dlen = length(data);
fltr = ones(1,5);                           % Filter
Flen = length(fltr);
datax = [data ones(1,Flen)*mean(data)];     % Pad ‘data’ vector with ones*mean(data)
mavg = [];
for k1 = 1:(Dlen)
    mavg = [mavg (fltr * datax(k1:k1+Flen-1)')/Flen];
end

figure(1)
plot([1:Dlen], data)
hold on
plot([1:Dlen], mavg, '-r')
hold off
grid

[Jan]

The iterative growing of the output vector is extremely inefficient. Look for the term "pre-allocation" in this forum to find faster methods.

You can avoid a lot of divisions, if you apply the /FLen once to fltr instead of doing this in each iteration.