Octave operator -: automatic broadcasting operation applied

Question

In octave 3.6.2, I have a matrix X=[1 2 3; 2 4 5; 2 6 5; 2 3 7; 3 6 8; 2 4 6; 3 6 8; 4 7 10] and I want to calculate X-mean(X), which gives me:

octave:2> X-mean(X)
warning: operator -: automatic broadcasting operation applied
ans =

  -1.37500  -2.75000  -3.50000
  -0.37500  -0.75000  -1.50000
  -0.37500   1.25000  -1.50000
  -0.37500  -1.75000   0.50000
   0.62500   1.25000   1.50000
  -0.37500  -0.75000  -0.50000
   0.62500   1.25000   1.50000
   1.62500   2.25000   3.50000

however, when I try the same command on a different machine, it complains that the sizes of matrices do not match:

error: operator -: nonconformant arguments (op1 is 7x3, op2 is 1x3)

Any idea how to activate that "automatic broadcasting operation" which is applied in the first case? (octave versions are the same!)

Answer 1

You can explicitly request broadcasting by calling bsxfun(operation, A, B), so in your case:

bsxfun(@minus, X, mean(X))

Octave reference, Matlab reference