MATLAB: Error using diff(X) command

diff(x)floating point

Hello all,
I am trying to store the difference of vector elements into an other vector. I have also seen the syntax using help command but still it persists.
Here is what I do
X = [1 1 2 3 5 8 13 21];
Y = diff(X)
the erorr is : Index exceeds matrix dimensions.
when I do difference of decimal numbers like
X = [0.001 0.001 0.002 0.003 0.005 0.008 0.0013 0.0021];
Y = diff(X)
Error says : "Subscript indices must either be real positive integers or logicals."
If diff(X) is only valid for integers, can some one suggest which alternative to use getting difference of adjacent decimal(floating point) elements of vector.
Regards Abdullah

Best Answer

You probably have a workspace variable named diff