Running average using for loops

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Matthew Healy
Matthew Healy 2019-3-13
评论： Matthew Healy 2019-3-15
I am tasked with writing a code which calculating a running average using a for loop on any desired file with any number of 'n' - samples and plot it against the raw data. This is how far I've managed to get, it runs with samples of 1 but everything above that it throws an error on lines 3 and 22. Any guidance is greatly appreciated.
edit: I've attached the file of the data I'm attempting to average and added the error messages I recieved.
%number of samples
n = input('enter sample amount: ');
%file of data
s = input('enter file name: ','s');
%function name
b = run_avg(n,s);
a = load(s);
%plot of raw data against the averaged data
plot(1:length(b),b, 1:length(a),a);
function avg = run_avg(n,s)
a = load(s);
x = length(a);
b = zeros(1,x);
%for loop to filter data of uploaded file.
for i = 1:x
%for the beginning of data set
if i < n-2
for j= i:i+(n-1)
b(i) = b(i) + a(j);
end
end
if i > n-2
for j = i - (n-1)/2 : i + (n-1)/2
b(i) = b(i) + a(j);
end
end
end
avg = b/n;
end
%error message
Array indices must be positive integers or logical values.
Error in run_av6>run_avg (line 22)
b(i) = b(i) + a(j);
Error in run_av6 (line 3)
b = run_avg(n,s);
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Rik
Rik 2019-3-14
In my first comment I linked to the Wikipedia page for minimal working example. So you need to provide a resonable value for n, as well as a reasonable value for s. Once you have provided those we can help you further.
As for you code itself, it is still unclear to me what you are doing. Try to explain why you have two inner loops separated by some logic. Why are you using those logical statements? What do they mean? Try to write a comment for each line.
The way I would write a window average is either with a convolution, or with a single loop.
Matthew Healy
Matthew Healy 2019-3-15
Thank you for your guidance. I scrapped the majority of what I wrote and used your advice for a window average combined with a convolution along with the code you provided. Again I am incredibly grateful for your patience and consistency in helpin me figure this out.

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采纳的回答

Rik
Rik 2019-3-13
I guess boldly:
If you want a sliding window average, you can use a convolution:
data=magic(8);data=data(:);%generate some data
x=linspace(0,1,numel(data));%generate some x-values
%create the filter kernel
window_kernel=[1 1 1 1];window_kernel=window_kernel/sum(window_kernel);
%apply convolution
new_data=conv(data,window_kernel,'same');
%plot
figure(1),clf(1)
plot(x,data,'r','DisplayName','raw')
hold on
plot(x,new_data,'b','DisplayName','filtered')
hold off
legend
  1 个评论
Matthew Healy
Matthew Healy 2019-3-13
Thank you but I need the average to be calculate through a for loop, I realize I didnt state this in the question sorry for the miscommunication.

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