First, know that arrayfun basically has a for-loop in it, so I am not sure you will gain speed. Also, since you operate on 4 elements at a time, I don’t know if arrayfun can do what you want.

You can try by making an anonymous function containing your string, something like:

f = @(databuffer,itr) typecast(databuffer(1:4, itr), ‘uint32′);

Then try using it, or some variant, with arrayfun. Again, I don’t think you’ll get speed up because arrayfun has essentially a for loop running it.

–loren

What I’am doing….

buffer = fread(fid,[4 count],'*uint8');
for itr = 1:count
    data(itr,1) = typecast(databuffer(1:4,itr),'uint32')
end

I would like to get rid of the for loop using arrayfun but don not understand how to pass the type string to the annonymous function

Thanks

arrayfun(@(i)(bsxfun(@minus,A,B(i,:))),1:size(B,1),'UniformOutput',false)

I don’t think arrayfun is the best tool for the job here. This can be easily vectorized, though I don’t know what you want for the diagonals when i == j; I’ll assume 0 for now. I haven’t tried this, but something like this should work.

d = diag(C);
A = m*diag(d)\C/diag(d);
[mm,mm] = size(A);  % assuming A is square
A(1:(mm+1):end) = 0; % fill diagonals

–Loren

I have a matrix C 670×670, I would like to perform this calculation on every element in C, the equation is:

m = some constant
Aij = (m * Cij) / (Cii * Cjj) Where i != j

Is it possible to do that without using for loops?
Thanks,

The following maybe what you are looking for.
http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=16467&objectType=FILE

I wrote it so I did not have to explicitly write loops or always write code that could take dim as an input.

The benefit is not speed but clear compact writing of code.

StephenLL

No, there is not function per se that works on each column. However, many MATLAB functions do operate on columns such as sum, mean, fft. You could write an anonymous function that takes a matrix and works on each column (using something like A(:,i) ). If you have a detailed question, I recommend you contact technical support to help with the specific issues.

–Loren

arrayfuncion works on each array element,
is there a function which operates on each colon?

Thanks,
Dani.

Stephen

Why can’t we have Outer in Matlab? Then we can say
Outer(@(a,b)a.^b,x,powers) — so much easier, nicer, and keeping with Matlab Spirit.

Maybe you can somehow implement Outer with arrayfun?