element wise operation - MATLAB

Question

I have a matrix in MATLAB, lets say:

a = [
  89  79  96  
  72  51  74  
  94  88  87  
  69  47  78
]

I want to subtract from each element the average of its column and divide by the column's standard deviation. How can I do it in a way which could be implemented to any other matrix without using loops.

thanks

Answer 1

If your version supports bsxfun (which is probably the case unless you have very old matlab version), you should use it, it's much faster than repmat, and consumes much less memory. You can just do: result = bsxfun(@rdivide,bsxfun(@minus,a,mean(a)),std(a))