## CUMSUM Cumulative Summation Function

Section: Elementary Functions

### Usage

Computes the cumulative sum of an n-dimensional array along a given dimension. The general syntax for its use is
y = cumsum(x,d)

where x is a multidimensional array of numerical type, and d is the dimension along which to perform the cumulative sum. The output y is the same size of x. Integer types are promoted to int32. If the dimension d is not specified, then the cumulative sum is applied along the first non-singular dimension.

### Function Internals

The output is computed via

### Example

The default action is to perform the cumulative sum along the first non-singular dimension.
--> A = [5,1,3;3,2,1;0,3,1]

A =
5 1 3
3 2 1
0 3 1

--> cumsum(A)

ans =
5 1 3
8 3 4
8 6 5

To compute the cumulative sum along the columns:

--> cumsum(A,2)

ans =
5 6 9
3 5 6
0 3 4

The cumulative sum also works along arbitrary dimensions

--> B(:,:,1) = [5,2;8,9];
--> B(:,:,2) = [1,0;3,0]

B =

(:,:,1) =
5 2
8 9

(:,:,2) =
1 0
3 0

--> cumsum(B,3)

ans =

(:,:,1) =
5  2
8  9

(:,:,2) =
6  2
11  9