Section: Inspection Functions
x.  The syntax for its use
is 
y = length(x)
and is defined as the maximum length of x along any of its
dimensions, i.e., max(size(x)).  If you want to determine the
number of elements in x, use the numel function instead.
4 x 4 x 3 matrix, the length is 4, not 48, as you 
might expect.
--> x = rand(4,4,3); --> length(x) ans = 4