Thread Subject: difference between filter and movavg output

Hi,

I am currently using the filter function to calculate an exponential moving average with the following code:

a=2/(N+1);
coef=repmat(1-a,1,N).^(1:N);
ema=filter(coef,sum(coef),data);

Which seems to work fine, however, when I use a for loop to calculate the same EMA I am getting different results. The for loop is as follows:

a=2/(N+1);
ema=zeroes(length(data),1);
ema(1)=data(1);
for i=2:length(data);
     ema(i)=ema(i-1)+a.*(data(i)-ema(i-1))
end

Using the "movavg" function gives the same results as above.
Has anyone any idea as to why these 2 methods are providing different results?
If so, could you please point out where my errors are?

Sorry can't help U...

i only have one question:

N is the number of points that u got?

Best Regards

CSA