Any ideas how i can reduce the execution time?

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Dennis_Pana 2016-7-19

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https://ww2.mathworks.cn/matlabcentral/answers/296404-any-ideas-how-i-can-reduce-the-execution-time

回答： Dennis_Pana 2016-7-20

newdes=[0.6250 0.8750; 0.2500 0.7500; 0.3750 0.1250;
 0.8750 0.3750; 0.1250 0.6250; 0 0; 0.5000 0.5000; 0.7500 0.2500;
 0.6875 0.0625; 0.0625 0.8125; 0.1875 0.6875; 0.3125 0.3125;
 0.4375 0.9375; 0.5625 0.5625; 0.9375 0.1875; 0.8125 0.4375;] ;      
                      dis=zeros(v,1);
                v=16;
                m=2;
                sum=0
                s=2;
                   for j=1:v
                   for k=1:m
                    ddii=(newdes(s,k)-newdes(j,k))^2;%Distance calculation of point s at its new location with all the other points.
                    sum=sum+ddii;
                   end
                    dis(j,1)=sum; %Store all the distances.
                    sum=0;
                        end

I am trying to use bxsfun, but i cannot solve it. I want reduce the time effort. Thank you in advance.

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Answer 1

Dennis_Pana 2016-7-20

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https://ww2.mathworks.cn/matlabcentral/answers/296404-any-ideas-how-i-can-reduce-the-execution-time#answer_229272

在 MATLAB Online 中打开

        xx=bsxfun(@minus,newdes(s,:),newdes(1:v,:));
        sbs=xx.^2;
        dis(:,1)=sum(sbs,2);

That is what i was looking for.

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Answer 2

Azzi Abdelmalek 2016-7-19

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https://ww2.mathworks.cn/matlabcentral/answers/296404-any-ideas-how-i-can-reduce-the-execution-time#answer_229160

在 MATLAB Online 中打开

newdes=[0.6250 0.8750; 0.2500 0.7500; 0.3750 0.1250;
  0.8750 0.3750; 0.1250 0.6250; 0 0; 0.5000 0.5000; 0.7500 0.2500;
  0.6875 0.0625; 0.0625 0.8125; 0.1875 0.6875; 0.3125 0.3125;
  0.4375 0.9375; 0.5625 0.5625; 0.9375 0.1875; 0.8125 0.4375;] ;
[nn,mm]=size(newdes)
v=16;
m=2;
s=2;
ay=repmat(1:m,1,v)
ax=s*ones(1,numel(ay))
idx1=sub2ind([nn mm],ax',ay')
[xx,yy]=meshgrid(1:v,1:m)
idx2=sub2ind([nn mm],xx(:),yy(:))
ww=(newdes(idx1)-newdes(idx2)).^2  %Distance calculation of point s at its new location with all the other points.
dis1=sum(reshape(ww,2,[]))'

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Azzi Abdelmalek 2016-7-19

编辑：Azzi Abdelmalek 2016-7-19

在 MATLAB Online 中打开

I made some improvement, but it's less faster. Sometimes for loop is more efficient!

[nn,mm]=size(newdes);
s=2;
ay=repmat(1:mm,nn,1);
ax=s*ones(size(ay));
idx1=reshape(sub2ind([nn mm],ax',ay'),mm,[]);
[xx,yy]=meshgrid(1:v,1:m);
idx2=sub2ind([nn mm],xx,yy);
ww=(newdes(idx1)-newdes(idx2)).^2 ; %Distance calculation of point s at its new location with all the other points.
dis1=sum(ww)';