Drexel dragonThe Math ForumDonate to the Math Forum


Math Forum
 Ask Dr. Math
 Discussions
 Internet Newsletter
 MathTools
 Problems of the Week
 Teacher2Teacher
 Teacher Exchange
 Workshops

Search All of the Math Forum:
Browse our Internet Mathematics Library

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » Software » comp.soft-sys.matlab

Topic: subtract vector from matrix rows without for loop
Replies: 6   Last Post: Dec 6, 2012 11:49 PM

Advanced Search
Reply to this Topic Reply to this Topic

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Remus

Posts: 4
Registered: 7/31/11
Re: subtract vector from matrix rows without for loop
Posted: Dec 6, 2012 11:49 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

"Matt J" wrote in message <hesupb$i07$1@fred.mathworks.com>...
> "Patrick Diviacco" <patrick.diviacco@gmail.com> wrote in message <hesm3s$3sn$1@fred.mathworks.com>...
> > hi,
> >
> > can I subtract the same vector to each row of a matrix without using a for loop ?
> > thanks
>
> For loops may be optimal (looping along the smallest dimension of the matrix), when the smallest dimension is small enough.

I like Matt's answer... here is another way of doing it, slightly more efficient.

A = magic(3);
B = [ 1 2 3];
C = A-diag(B)*ones(size(A));

In essence is the same thing.

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2013. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.