## DIFF Difference Function

Section: Elementary Functions

### Usage

y=diff(x) y=diff(x,k) y=diff(x,k,dim)

Produce difference of successive vector elements.
If `x`

is a vector of length n, `diff (x)`

is the
vector of first differences
\[
[x_2 - x_1, ..., x_n - x_{n-1}].
\]
If `x`

is a matrix, `diff (x)`

is the matrix of column
differences along the first non-singleton dimension.
The second argument is optional. If supplied, `diff (x,k)`

,
where `k`

is a nonnegative integer, returns the
`k`

-th differences. It is possible that `k`

is larger than
then first non-singleton dimension of the matrix. In this case,
`diff`

continues to take the differences along the next
non-singleton dimension.
The dimension along which to take the difference can be explicitly
stated with the optional variable `dim`

. In this case the
`k`

-th order differences are calculated along this dimension.
In the case where `k`

exceeds `size (x, dim)`

then an empty matrix is returned.