> ## Documentation Index
> Fetch the complete documentation index at: https://numpyts.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Cumulative Operations

> Cumulative sum and product functions: cumsum, cumprod, cumulative_sum, cumulative_prod.

# Cumulative Operations

Cumulative operations return an array of the same size as the input, where each element is the running total (sum or product) of all preceding elements along the specified axis.

***

### cumsum

Return the cumulative sum of elements along a given axis.

<Note>
  Also exported as `cumulative_sum` for compatibility with the newer NumPy naming convention.
</Note>

```typescript theme={null}
function cumsum(
  a: ArrayLike,
  axis?: number
): NDArray;
```

| Parameter | Type        | Default     | Description                                                                                                |
| --------- | ----------- | ----------- | ---------------------------------------------------------------------------------------------------------- |
| `a`       | `ArrayLike` | --          | Input array.                                                                                               |
| `axis`    | `number`    | `undefined` | Axis along which to compute the cumulative sum. When `undefined`, the input is flattened before computing. |
| `dtype`   | `DType`     | `undefined` | Desired output dtype. If `undefined`, the dtype is inferred from the input.                                |

**Returns:** `NDArray` containing the cumulative sums.

```typescript theme={null}
import { array, cumsum } from 'numpy-ts';

const a = array([1, 2, 3, 4]);
cumsum(a); // array([1, 3, 6, 10])

const b = array([[1, 2], [3, 4]]);
cumsum(b);    // array([1, 3, 6, 10])   -- flattened
cumsum(b, 0); // array([[1, 2], [4, 6]])
cumsum(b, 1); // array([[1, 3], [3, 7]])
```

***

### cumprod

Return the cumulative product of elements along a given axis.

<Note>
  Also exported as `cumulative_prod` for compatibility with the newer NumPy naming convention.
</Note>

```typescript theme={null}
function cumprod(
  a: ArrayLike,
  axis?: number
): NDArray;
```

| Parameter | Type        | Default     | Description                                                                                                    |
| --------- | ----------- | ----------- | -------------------------------------------------------------------------------------------------------------- |
| `a`       | `ArrayLike` | --          | Input array.                                                                                                   |
| `axis`    | `number`    | `undefined` | Axis along which to compute the cumulative product. When `undefined`, the input is flattened before computing. |
| `dtype`   | `DType`     | `undefined` | Desired output dtype. If `undefined`, the dtype is inferred from the input.                                    |

**Returns:** `NDArray` containing the cumulative products.

```typescript theme={null}
import { array, cumprod } from 'numpy-ts';

const a = array([1, 2, 3, 4]);
cumprod(a); // array([1, 2, 6, 24])

const b = array([[1, 2], [3, 4]]);
cumprod(b);    // array([1, 2, 6, 24])    -- flattened
cumprod(b, 0); // array([[1, 2], [3, 8]])
cumprod(b, 1); // array([[1, 2], [3, 12]])
```