# frac

**Repository Path**: ArkTSCentralRepository/frac

## Basic Information

- **Project Name**: frac
- **Description**: frac 是一个用于将浮点数近似为有界分母的有理数的库，提供了通过中介法和Aberth的连续分数算法进行有理数近似的功能。
- **Primary Language**: Unknown
- **License**: Apache-2.0
- **Default Branch**: main
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2024-11-21
- **Last Updated**: 2024-11-23

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# frac
基于[frac](https://www.npmjs.com/package/frac)原库1.1.2版本进行适配, 所有功能代码已经转换为`ArkTS`文件

## Install
```sh
ohpm install frac
```

## Description

Rational approximation to a floating point number with bounded denominator.

Uses the [Mediant Method](https://en.wikipedia.org/wiki/Mediant_method).

This module also provides an implementation of the continued fraction method as
described by Aberth in "A method for exact computation with rational numbers".
The algorithm is used in <a href="http://sheetjs.com">SheetJS Libraries</a> to
replicate fraction formats.

## Usage

In all cases, the relevant function takes 3 arguments:

 - `x` the number we wish to approximate
 - `D` the maximum denominator
 - `mixed` if true, return a mixed fraction; if false, improper

The return value is an array of the form `[quot, num, den]` where `quot==0`
for improper fractions.  `quot <= x` for mixed fractions, which may lead to some
unexpected results when rendering negative numbers.

### Example

The exported `frac` function implements the Mediant method.

`cont` implements the Aberth algorithm

For example:

```typescript
> // var frac = require('frac'); // uncomment this line if in node
> frac(1.3, 9);              // [  0,  9, 7 ] //  1.3 ~       9/7
> frac(1.3, 9, true);        // [  1,  2, 7 ] //  1.3 ~  1 +  2/7
> frac(-1.3, 9);             // [  0, -9, 7 ] // -1.3 ~      -9/7
> frac(-1.3, 9, true);       // [ -2,  5, 7 ] // -1.3 ~ -2 +  5/7

> cont(1.3, 9);         // [  0,  4, 3 ] //  1.3 ~       4/3
> cont(1.3, 9, true);   // [  1,  1, 3 ] //  1.3 ~  1 +  1/3
> cont(-1.3, 9);        // [  0, -4, 3 ] // -1.3 ~      -4/3
> cont(-1.3, 9, true);  // [ -2,  2, 3 ] // -1.3 ~ -2 +  2/3
```

## License

Please consult the attached LICENSE file for details.  All rights not explicitly
granted by the Apache 2.0 License are reserved by the Original Author.

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