From matrix column subtract corresponding vector value

Question

I have a matrix 'x' and a row vector 'v'; the number of elements in the row vector is the same as the number of columns in the matrix. Is there any predefined function for doing the following operation?

for c = 1 : columns(x)
    for r = 1 : rows(x)
        x(r, c) -= v(c);
    end
end

Answer 1

bsxfun(@minus,x,v)

Here's an octave demonstration:

octave>  x = [1 2 3;2 3 4]
x =

   1   2   3
   2   3   4

octave> v = [2 0 1]
v =

   2   0   1

octave> 
octave> z=bsxfun(@minus,x,v)
z =

  -1   2   2
   0   3   3

Answer 2

If you are using Octave 3.6.0 or later, you don't have to use bsxfun since Octave performs automatic broadcasting (note that this is the same as actually using bsxfun, just easier on the eye). For example:

octave>  x = [1 2 3; 2 3 4]
x =

   1   2   3
   2   3   4

octave> v = [2 0 1]
v =

   2   0   1

octave> z = x - v
z =

  -1   2   2
   0   3   3