How do I preallocate this loop?
1 vue (au cours des 30 derniers jours)
Afficher commentaires plus anciens
Hello
I'm trying to make my program run faster and it suggests to preallocate this loop. Anyone know how convert this loop?
% code
for i = 1:1:5
z(i) = x(zipfind - 1 + i);
end
Thanks!
0 commentaires
Réponse acceptée
Evan
le 8 Août 2013
Modifié(e) : Evan
le 8 Août 2013
Here is the loop with preallocation:
z = zeros(5,1) % preallocation
for i = 1:1:5
z(i) = x(zipfind - 1 + i);
end
Also, it looks as if you could possibly remove the looping altogether:
x = randi(20,20,1);
zipfind = randi(20);
zloop = zeros(5,1);
for i = 1:5
zloop(i) = x(zipfind - 1 + i);
end
zvec = x(zipfind - 1 + (1:5));
And compare the results of zloop and zvec:
>>zvec
zvec =
14
4
3
10
20
>> zloop
zloop =
14
4
3
10
20
So, basically, you could just replace that entire loop with:
z = x(zipfind - 1 + (1:5));
0 commentaires
Plus de réponses (0)
Voir également
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!