Uncumulate

Uncumulate(x,I, firstElement)

Finds the difference between each element of x and its predecessor along I.

Uncumulate(x, i) returns an array whose first element (along i) is the first element of x, and each other element is the difference between the corresponding element of x and the previous element of x. Uncumulate(x, i, firstElement) returns an array with the first element along i equal to firstElement, and each other element equal to the difference between the corresponding element of x and the previous element of x.

Uncumulate(x, i) is the inverse of Cumulate(x, i). Uncumulate(x, i, 0) is similar to a discrete differential operator.

Examples

I →	1	2	3	4	5	6
X →	8	10	10	15	12	19
Uncumulate(X,I) →	8	2	0	5	-3	7

Uncumulate(Cost_of_ownership, Time) → Car_type ↓ , Time ↑

	0	1	2	3	4
VW	2810	141	147	155	163
Honda	3535	312	50	269	199
BMW	3185	109	115	120	127

Uncumulate(Cost_of_ownership, Time,0) → Car_type ↓ , Time ↑

	0	1	2	3	4
VW	0	141	147	155	163
Honda	0	312	50	269	199
BMW	0	109	115	120	127

See “Example variables” on page 190 for example array variables used here and below.

See Also

• Cumulate
• Example variables