cost funtion between observed and measured .

I have two matrices of different size and would like to calculate cost funtion between observed and measured . As I search through I came across the following fnction Diff=measured-observed.^2,2).Can somebody explain this fuction for me. What does 2 just after the exponent do?I would appreciates some explanation. Thanks in advance

Answer 1

[David Sanchez]

From Matlab documentation:

In general, diff(X) returns the differences calculated along the first non-singleton (size(X,dim) > 1) dimension of X.

Y = diff(X,n) applies diff recursively n times, resulting in the nth difference. Thus, diff(X,2) is the same as diff(diff(X)).