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

The following example returns a table that shows an increase in the cost ownership of certain car types over a certain period of time.

Uncumulate (Cost_of_ownership, Time)→

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

The next example returns a table that shows the increase in the cost of ownership of cars compared to the previous time period and also sets the first value to 0.

Uncumulate (Cost_of_ownership, Time, 0)→

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

See Also

• Cumulate
• Example variables
• User Guide Examples / Array Function Examples.ana / Reducing Functions Module