# Multiply each column of n-by-m matrix by respective constants in m-by-1 vector

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Jesper on 21 Jan 2012
Commented: Steven Lord on 23 Jul 2021
Hi
I have an n-by-m matrix and an m-by-1 vector. I want to multiply each of the m columns in the matrix by a constant specified in my vector.
E.g. if I have a matrix A=[1,2;3,4;5,6] and a vector B=[0.5,2] I want to multiply all the elements in the first column of my matrix by 0.5 and alle the elements en the second column by 2. That is, I would like to get the result C=[0.5,4;1.5,8;2.5,12].
It can easily be done by a loop, but I would like to know if the is a faster way to do this. A built in functionality? Dot-multiply doesn't seem to do the trick :(
- Jesper

the cyclist on 21 Jan 2012
C = bsxfun(@times,A,B);

vlad ap on 22 Jul 2021
This also works:
C = B.*A
##### 2 CommentsShowHide 1 older comment
Steven Lord on 23 Jul 2021
This works now due to implicit expansion. It would not have worked when the question was first asked in 2012.

Jesper on 21 Jan 2012
Hi Cyclist
This was exactly what I needed ;)
Thanks!
- Jesper
the cyclist on 21 Jan 2012
Happy to help. For future reference, you might want to add a remark like this as a "comment" to an answer (like I did here), rather than as a separate "answer". On questions that have more activity than this one, it helps to keep things organized logically.