How subtract each element of row vector of size 1xN from column vector Mx1 without using loop in MatLab?
N = 1:100 M = ones(1000,1) 
1 Answer
You can use bsxfun as suggested by Daniel
out = bsxfun(@minus, N,M); but it might be more obvious to use meshgrid or ndgrid to get the matrix you want:
out = meshgrid(N-1,M); These two functions internally use repmat which is slower than bsxfun, so rather go for the first approach. And bsxfun is always the fastest solution anyway ;)
3 Comments
Luis Mendo
bsxfun for the win!
Andrea Ciarmiello
If the number of columns in vector and in Matrix are different bsxfun works all the way?... For e.g In my setting i have N=[12 33 2 45 8 1 67 5 58] M is a Matrix of 100 rows and 4 columns I need to subtract each element of N from each Matrix value can i do this with bsxfun? Thanks
Robert Seifert
@AndreaCiarmiello
bsxfun works for a = 1xN and b = Mx1 or a = MxN and b = MxN. What you want won't work, as it is unclear how the result should look like. You should post a new question with a minimal example and the desired output for a given input. There will be an efficient solution as well, but its a different question then. Please consider also accepting this answer, if it helped you for now.
bsxfun