# @keystonehq/alias-sampling

> A Node.js module for efficient sampling from a discrete probability distribution using the alias method.

Latest version **0.1.2** (published 2024-03-03) · MIT license · 0 weekly downloads

## Install

```sh
npm install @keystonehq/alias-sampling
pnpm add @keystonehq/alias-sampling
yarn add @keystonehq/alias-sampling
bun add @keystonehq/alias-sampling
```

## Health

**Score 30/100 (F)** — status: abandoned.

Positive: has types; esm support; no vulnerabilities; high quality score.

Warnings: low downloads; pre 1.0.

Negative: abandoned; low maintenance score.

## Facts

| | |
|---|---|
| Version | 0.1.2 |
| Published | 2024-03-03 |
| First published | 2024-02-26 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | bundled |
| Module format | ESM + CommonJS |
| Dependencies | 0 |
| Unpacked size | 10.1 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| Maintainers | yu_keyst, amalia20220301, liyanlance, keystoneorg, soralit |
| Keywords | alias method, sampling, probability distribution, random, statistics, math, discrete distribution |

## Links

- npm: https://www.npmjs.com/package/@keystonehq/alias-sampling
- npm.io page: https://npm.io/package/@keystonehq/alias-sampling

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## Recent versions

- 0.1.2 (latest) — 2024-03-03
- 0.1.1 — 2024-02-29
- 0.1.0 — 2024-02-27
- 0.0.7 — 2024-02-27
- 0.0.6 — 2024-02-27
- 0.0.5 — 2024-02-26
- 0.0.4 — 2024-02-26
- 0.0.3 — 2024-02-26
- 0.0.2 — 2024-02-26
- 0.0.1 — 2024-02-26

## README

# Alias Method for Sampling

A JavaScript library for efficient sampling of random values from a discrete probability distribution using the Walker-Vose alias method, provided by KeystoneHQ.

## Installation

Install the library using yarn:

```shell
yarn add @keystonehq/alias-sampling
```

Or npm:

```shell
npm install @keystonehq/alias-sampling
```

## Usage

To use the library, first import the `sample` function and then create a sampler with a given probability distribution and optionally an array of outcomes. You can then generate random samples using the `.next()` method.

### Basic Usage

```javascript
import sample from '@keystonehq/alias-sampling';

// Create a sampler with specified probabilities and outcomes
var s = sample([0.5, 0.25, 0.25], ['A', 'B', 'C']);

// Generate a single random outcome
console.log(s.next()); // => 'A', 'B', or 'C' according to specified probabilities
```

### Generating Multiple Samples

```javascript
import sample from '@keystonehq/alias-sampling';

// Create a sampler with specified probabilities
var s = sample([0.5, 0.25, 0.25], [10, 20, 30]);

// Generate multiple random samples
console.log(s.next(1000)); // => an array of 1000 random samples
```

### Sampling Indices

```javascript
import sample from '@keystonehq/alias-sampling';

// Create a sampler without specifying outcomes (defaults to indices)
var s = sample([0.5, 0.25, 0.25]);

// Generate a single random index
console.log(s.next()); // => 0, 1, or 2 with the specified probabilities
```

### Using a Custom Random Generator

```javascript
import sample from '@keystonehq/alias-sampling';

// Custom random generator function
var rand = Math.random;

// Create a sampler with specified probabilities and custom random generator
var s = sample([0.5, 0.25, 0.25], null, rand);

// Generate a random index using the custom random generator
console.log(s.next()); // => 0, 1, or 2 with the specified probabilities
```

---
_Source: https://npm.io/package/@keystonehq/alias-sampling · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._