A discrete difference means subtracting two successive elements.
E.g. for [1, 2, 3, 4], the discrete difference would be [2-1, 3-2, 4-3] = [1, 1, 1]
To find the discrete difference, use the diff() function.
Compute discrete difference of the following array:
import numpy as np
arr = np.array([10, 15, 25, 5])
newarr = np.diff(arr)
print(newarr)Returns: [5 10 -20] because 15-10=5, 25-15=10, and 5-25=-20
We can perform this operation repeatedly by giving parameter n.
E.g. for [1, 2, 3, 4], the discrete difference with n = 2 would be [2-1, 3-2, 4-3] = [1, 1, 1], then, since n=2, we will do it once more, with the new result: [1-1, 1-1] = [0, 0]
Compute discrete difference of the following array twice:
import numpy as np
arr = np.array([10, 15, 25, 5])
newarr = np.diff(arr, n=2)
print(newarr)Returns: [5 -30] because: 15-10=5, 25-15=10, and 5-25=-20 AND 10-5=5 and -20-10=-30