norm calculation using for loop

hello , can anybody tell me how to calculate l2 norm of x=[2 3 -5 3 1] using for loop and without loop, and which one is efficient and fast?

 采纳的回答

n = norm( x );
does it without a loop. There is no reason to do it with a loop. Even if you don't use norm you would still vectorise is as:
n = sqrt( sum( x.^2 ) );
If you really want a loop the derivation is not difficult though. The vectorised version should certainly be faster, but you can test this yourself.

4 个评论

g.p
g.p 2016-8-12
编辑:g.p 2016-8-12
thanks adam , but i have to perform it element-wise using for loop ,and without for loop and need to justify which is fast.
If you have to perform it with a loop then I assume it is homework which you should be able to work out yourself from the 2nd version I gave above.
Converting this into a loop just uses the basics of Matlab:
n = sqrt( sum( x.^2 ) );
did u calculate it using for loops? how?
As Adam has mentioned in his answer, loop is not necessary but if it's a homework and you must use a loop, then read the documentation to know how it works and then use the for loop iterator to index through the vector.

请先登录,再进行评论。

更多回答(0 个)

类别

帮助中心File Exchange 中查找有关 Loops and Conditional Statements 的更多信息

提问:

g.p
2016-8-12

评论:

KL
2017-10-16

Community Treasure Hunt

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

Start Hunting!

Translated by