How to vectorize nested for loops within a script

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Roba Kidse
Roba Kidse 2022-4-21
回答： Matt J 2022-4-21
%The script:
PopList = {popCA_1,popCA_2,popCA_3,popCA_4}; % PopList is a 1 by 4 cell with 30 by 1 struct
b = [b1,b2,b3,b4]; % b is a 1 by 4 struct with 1 by 1 struct
start = false;
for d = 1:4
lbest = b(d).Situational.accuracy;
for f = 1:30
data = PopList{d}(f);
PopList{d}(f) =newFunc(data,lbest,X,T);
end
PopList{d} = SortPop(PopList{d});
newBeliefs = PopList{d}(1:newBeliefNo);
worst = PopList{d}(nPop);
b(d) = UpdateBeliefSystem(b(d), newBeliefs, worst, start);
end
%The newFunc:
function [popdata] = newFunc(popdata,lbest,X,T)
featSize = size(X,2);
cProb = 0.2; % probability of change
nChange = round(cProb*featSize); % number of features changed
if (popdata.accuracy < lbest)
%apply change operator (flip the values at the gene location)%
f = randperm(featSize, nChange);
for i=1:size(f,2)
popdata.Position(f(i)) = mod(( popdata.Position(f(i)))+1,2);
end
f1 = find(popdata.Position ==1);
popdata.nfeat = size(f1,2);
X1 = X(:,(f1));
%
[popdata.accuracy, popdata.AUCval,popdata.mse,...
popdata.OPTROCPT,popdata.precision,popdata.F1,popdata.recall ] = knn(X1,T);
end
end

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回答（1 个）

Matt J
Matt J 2022-4-21
You cannot vectorize loops over cells and structs. In most cases, cells and structs are appropriate only for small data sizes (which appears to be your case as well), so there is usually no need to vectorize them.

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