I'm a beginner with Matlab so I'm sorry if this answer may sound silly to most of you who know MATLAB, but I'm stuck and cannot solve this matter. So thanks a lot in advance!
I'm trying to calculate the Approximate Entropy (ApEn) index of various respiratory variables acquired as a time-series with a breath-by-breath resolution. The machine gives me a for each subjects a .xls files with many columns as the different parameters (rows are the values of parameters per each breath). I need to calculate the ApEn for each subject for several of the parameter assessed by the machine.
There are at least a couple .m files available to calculate the ApEn. I'm able to make it work properly but it calculates the ApEn of only the first column (first respiratory variable) of the array.
There is a way to make it iteratively run the apen.m for ALL of the columns, so having n results as the number of the columns/variables in the data array?
Thank you again!
Hi Massimiliano
When you read xls file with xlsread you obtain a matrix with all the columns.
[A,B]=xlsread('file.xls','sheet')
I do not know how your m file works. I supouse that the input is one vector (excel column). If this is correct you can run your function to calculate ApEN changing the input column of the excel matrix.
for i=1:size(A,2)
ApEn(i)=yourmfile(A(:,i))
end
one general point, I'd like to mention: sort columns and rows in Excel not in Matlab. That'll save you a lot of time in almost any case.
Thank you so much for your reply!
the ApEn function is:
apen = ApEn( dim, r, data, tau )
where dim, r and tau are user-defined parameters and data is the variable containing the breath-by-breath values.
I was able to import the excel file but I'm experiencing some problems in making things work as you suggested above. Probably wronging something!
Thank you once again!
@Daniel Polterauer can you explain why Excel is better than MATLAB in this case?
There are sorting functions implemented in MATLAB:
http://www.mathworks.com/help/matlab/ref/sortrows.html
http://www.mathworks.com/help/matlab/ref/sort.html
It would be better if you copy and paste your error messages.
Try to type this in the command line replacing dim, r and tau with your values
for i=1:size(A,2); apen(i) = ApEn( dim, r, A(:,i), tau);end
or create a function in a new file an type in the command line "apen= multiple_collumn_APEN;"
function apen= multiple_collumn_APEN
[A,B]=xlsread('yourfile.xls','yoursheet')
for i=1:size(A,2)
apen(i) = ApEn( dim,r, A(:,i), tau);
end
I can't help you better without more info.
Now it works perfectly!!!
I finally got my 'apen' array with the 118 apen index calculated in just a couple of seconds!
Thank you so much Gonzalo!
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