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Preallocation for a cell help needed

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Amadeus
Amadeus 2012-12-10
Hello,
I could not find out how to properly do the preallocation for the following situation. Could you please give me a hand?
Regards
Size of tracks' changes every loop, so I want to do preallocation for it but could not figure out how. (Size of tracks(1,i).nPoints remains same. Only tracks(1,i).matrix changes, 1≤i≤max_n_trks)
%% Interpolation
interp=1;
for param=1:interp
for k=1:max_n_trks % maximum number of tracks
vector = tracks(1,k).matrix;
len = tracks(1,k).nPoints;
for i=len:-1:1
vector(2*i-1,:,:)=vector(i,:,:);
end
tracks(1,k).nPoints = (tracks(1,k).nPoints*2)-1;
len = tracks(1,k).nPoints;
for i=1:2:len-1
vector(i+1,:,:) = (vector(i,:,:) + vector(i+2,:,:))/2;
end
tracks(1,k).matrix = vector;
end
end
note: Now, I found a way:
B = struct('nPoints',repmat({zeros(1)},1,110470),'matrix2',repmat({zeros([n 3])},1,110470))
I can assign the maximum value that n can take, however I want to make it more efficient. How can I do it? For example tracks(1,1).matrix has 3 elements and tracks(1,133).matrix has 170 elements. I do not want to assign 170 to each, I want to separately do to assignment.

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采纳的回答

Sean de Wolski
Sean de Wolski 2012-12-10
It sounds like you should assign an empty cell to each value:
S = struct('field1',cell(10,1));
You can then fill in the values as necessary:
for ii = 1:10;
S(ii).field1 = magic(randperm(10,1));
end

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