`y=diff(x)`

`y=diff(x,k)`

Inputs | |

`x` |
A vector or a matrix. |

`k` |
A positive integer whose default value is assumed to be `1` . |

Outputs | |

`y` |
A vector or matrix of numbers computed by differencing the input `k` times. |

For a vector input,

`diff(x)`

returns the array `[ x[2]-x[1] , x[3]-x[2] , x[4]-x[3] ....]`

.
If

`x`

is a matrix, the finite differnces are calculated column by column.
`diff(x,k)`

calculate the `k'th`

difference by differencing the input array
`k`

times.
>>a=[4 10 12 15]'>>a4 10 12 15>>diff(a)6 2 3>>diff(a,2)-4 1>>diff(diff(a))-4 1