Compare matrix element without loops

2 vues (au cours des 30 derniers jours)
shdotcom shdotcom
shdotcom shdotcom le 4 Mai 2019
Commenté : dpb le 4 Mai 2019
Hi,
Is there any way to get same result without using loops?
G = [5 8; 8 5; 3 9; 7 3; 1 4; 5 10; 6 7; 4 10; 4 7; 1 6];
n = 2;
nG = size(G,1);
for ii=1:nG
zz =1;
isDom = [];
for kk=1:n
for jj=1:nG
if ii ~= jj
isDom(zz) = G(ii,kk) < G(jj,kk);
zz = zz +1;
end
end
end
R(ii) = sum(isDom==1);
end

Réponse acceptée

dpb
dpb le 4 Mai 2019
Modifié(e) : dpb le 4 Mai 2019
Not w/o zero loops, think not, but can reduce to one...
idx=1:nG; % working index array for element logical lookup/exclusion
R=zeros(nG,1); % preallocate
for i=1:nG
isDom=(G(i,:)-G(idx~=i,:));
R(i)=sum(isDom(:)<0);
end
You can eliminate the intermediate isDom temporary if desired..."exercise for the student" :)
  2 commentaires
shdotcom shdotcom
shdotcom shdotcom le 4 Mai 2019
Thank you
dpb
dpb le 4 Mai 2019
You can also, of course, remove the explicit loop via arrayfun, but the loop is still there and resulting code is somewhat obfuscated and may well be slower, besides...

Connectez-vous pour commenter.

Plus de réponses (0)

Catégories

En savoir plus sur Loops and Conditional Statements dans Help Center et File Exchange

Produits

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by