Mapping a function over each cell in a cell array using arrayfun

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Hi,
I am trying to "map" a function over each cell in a cell array. For example, suppose that I have a cell array which is filled with vectors of the same length:
C=cell(2,2);
C(1,1)={[1,1]};
C(1,2)={[2,2]};
C(2,1)={[3,3]};
C(2,2)={[4,4]};
Now I wish to apply the built-in Matlab function "norm" to each element in the cell array and return the results in an array (a regular, numeric array/matrix). I tried the following:
myresult=arrayfun(@(M,N) norm(cell2mat(C(M,N))),1:size(C,1),1:size(C,2))
But of course this does not give me what I really want; it gives me the following:
myresult =
1.4142 5.6569
which is only the norm of the (1,1) element (note that sqrt(1.^2 + 1.^2) = 1.4142) and the norm of the (2,2) element (note that sqrt(4.^2 + 4.^2) = 5.6569). This is because in my code, by specifying M as 1:size(C,1) and N as 1:size(C,2), the function is only evaluated at (M,N)=(1,1) and (M,N)=(2,2).
Can you please help me to see how I can modify my code to take the norm of all the arrays stored in the cell array C?
Thanks in advance,
Andrew DeYoung
Carnegie Mellon University

Accepted Answer

Walter Roberson
Walter Roberson on 10 May 2011
myresult = arrayfun(@(c) norm(c{1}), C);
Or more compactly,
myresult = cellfun(@norm,C);

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