Error on Matlab coder

function [nearest]=kdtree_search(data,K)

    numDP=size(data.X,1);
    P=data.X;
    DIM=size(data.X,2);
    nearest=zeros(numDP,K);
    nsorted=cell(numDP,1);
    distance=cell(numDP,DIM);
    F=cell(numDP,DIM); 
    for i=1:numDP
        for jg=2:numDP
            
            F{jg}=(P(jg,:)-(P(i,:)));
            distance{i}=sqrt(sum(((F{jg}).^2),2));            %THIS LINE
            [~,nsorted{i}]=sortrows(distance{i},'ascend');
            nearest(i,:)=nsorted{i}(2:K+1)';

While using this code I always get arror in the line that i highlighted bold. It gives size match errror during calculation but i want to do this code faster as it can possible.

[Walter Roberson]

Please post the complete error message.

[Zeynep Naz Kocabas]

[Walter Roberson]

The error is correct: F{1} is never assigned to.

I notice by the way, that you appear to be using a symmetric distance measurement. That would suggest that you should be using

for i=1:numDP-1
  for jg=i+1:numDP

As you are not saving the F values outside of the for jg loop (you would need a 2D cell array for that), I wonder if you even need to save them at all? Are you accessing the F entries after the for jg loop?

I also see

     distance=cell(numDP,DIM);

but you are assigning to distance{i} not to a 2D location, and you are overwriting distance{i} every iteration of your for jg loop.

[Zeynep Naz Kocabas]

Should I not use

distance=cell(numDP,DIM);

Yes i don't use F after the loop.

And thank you for your help.

[Walter Roberson]

function [nearest]=kdtree_search(data,K)
    numDP = size(data.X,1);
    P = data.X;
    nearest = zeros(numDP,K);
    distance = zeros(numDP,numDP);
    for i=1:numDP
        for jg=i+1:numDP
            F=(P(jg,:)-(P(i,:)));
            distance(i,jg) = sqrt(sum(((F).^2),2));
            distance(jg,i) = distance(i,jg);   %symmetric
            [~,nsorted]=sortrows(distance{i},'ascend');
            nearest(i,:)=nsorted(2:K+1)';
        end
    end

[Zeynep Naz Kocabas]

Thank you very much.