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Section: Elementary Functions
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.