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.
The output is computed via
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 =
<int32> - size: [3 3]
Columns 1 to 3
5 1 3
3 2 1
0 3 1
--> cumsum(A)
ans =
<int32> - size: [3 3]
Columns 1 to 3
5 1 3
8 3 4
8 6 5
To compute the cumulative sum along the columns:
--> cumsum(A,2)
ans =
<int32> - size: [3 3]
Columns 1 to 3
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 =
<int32> - size: [2 2 2]
(:,:,1) =
Columns 1 to 2
5 2
8 9
(:,:,2) =
Columns 1 to 2
1 0
3 0
--> cumsum(B,3)
ans =
<int32> - size: [2 2 2]
(:,:,1) =
Columns 1 to 2
5 2
8 9
(:,:,2) =
Columns 1 to 2
6 2
11 9