Calculates the 2 point series difference.
DIFF(series)
series |
- |
A series. The input. |
A series or array.
W1: {1, -2, 2, -1};setdeltax(1/10)
W2: diff(w1)
W3: rderiv(w1, 1)
W2 == {-3, 4, -3}
W3 == {-30, -40, -30, 10}
W2 computes the 2 point difference. The DELTAX of the data is ignored. RDERIV performs a similar calculation but the result is divided by DELTAX.
DIFF computes the 2 point series difference defined as:
DIFF is similar to the 2 point right derivative as computed by RDERIV:
however for DIFF, the length of the result is 1 less than the input length and the result is independent of DELTAX.