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https://github.com/primaryobjects/lda
LDA topic modeling for node.js
https://github.com/primaryobjects/lda
ai artificial-intelligence javascript keywords language lda machine-learning natural-language-processing nlp node node-js nodejs topic-modeling topics
Last synced: 2 days ago
JSON representation
LDA topic modeling for node.js
- Host: GitHub
- URL: https://github.com/primaryobjects/lda
- Owner: primaryobjects
- License: apache-2.0
- Created: 2014-05-27T17:35:48.000Z (over 10 years ago)
- Default Branch: master
- Last Pushed: 2024-08-20T21:54:11.000Z (5 months ago)
- Last Synced: 2025-01-03T22:09:00.061Z (9 days ago)
- Topics: ai, artificial-intelligence, javascript, keywords, language, lda, machine-learning, natural-language-processing, nlp, node, node-js, nodejs, topic-modeling, topics
- Language: JavaScript
- Homepage:
- Size: 44.9 KB
- Stars: 292
- Watchers: 7
- Forks: 49
- Open Issues: 2
-
Metadata Files:
- Readme: Readme.md
- Funding: .github/FUNDING.yml
- License: LICENSE
Awesome Lists containing this project
- awesome-topic-models - lda-nodejs - Node.js implementation of LDA topic modeling (Models / Latent Dirichlet Allocation (LDA) [:page_facing_up:](https://www.jmlr.org/papers/volume3/blei03a/blei03a.pdf))
README
LDA
--------
Latent Dirichlet allocation (LDA) topic modeling in javascript for node.js.
LDA is a machine learning algorithm that extracts topics and their related keywords from a collection of documents.
In LDA, a document may contain several different topics, each with their own related terms. The algorithm uses a probabilistic model for detecting the number of topics specified and extracting their related keywords. For example, a document may contain topics that could be classified as beach-related and weather-related. The beach topic may contain related words, such as sand, ocean, and water. Similarly, the weather topic may contain related words, such as sun, temperature, and clouds.
See http://en.wikipedia.org/wiki/Latent_Dirichlet_allocation
```bash
$ npm install lda
```
## Usage
```javascript
var lda = require('lda');
// Example document.
var text = 'Cats are small. Dogs are big. Cats like to chase mice. Dogs like to eat bones.';
// Extract sentences.
var documents = text.match( /[^\.!\?]+[\.!\?]+/g );
// Run LDA to get terms for 2 topics (5 terms each).
var result = lda(documents, 2, 5);
```
The above example produces the following result with two topics (topic 1 is "cat-related", topic 2 is "dog-related"):
```
Topic 1
cats (0.21%)
dogs (0.19%)
small (0.1%)
mice (0.1%)
chase (0.1%)
Topic 2
dogs (0.21%)
cats (0.19%)
big (0.11%)
eat (0.1%)
bones (0.1%)
```
## Output
LDA returns an array of topics, each containing an array of terms. The result contains the following format:
```
[ [ { term: 'dogs', probability: 0.2 },
{ term: 'cats', probability: 0.2 },
{ term: 'small', probability: 0.1 },
{ term: 'mice', probability: 0.1 },
{ term: 'chase', probability: 0.1 } ],
[ { term: 'dogs', probability: 0.2 },
{ term: 'cats', probability: 0.2 },
{ term: 'bones', probability: 0.11 },
{ term: 'eat', probability: 0.1 },
{ term: 'big', probability: 0.099 } ] ]
```
The result can be traversed as follows:
```javascript
var result = lda(documents, 2, 5);
// For each topic.
for (var i in result) {
var row = result[i];
console.log('Topic ' + (parseInt(i) + 1));
// For each term.
for (var j in row) {
var term = row[j];
console.log(term.term + ' (' + term.probability + '%)');
}
console.log('');
}
```
## Additional Languages
LDA uses [stop-words](https://en.wikipedia.org/wiki/Stop_words) to ignore common terms in the text (for example: this, that, it, we). By default, the stop-words list uses English. To use additional languages, you can specify an array of language ids, as follows:
```javascript
// Use English (this is the default).
result = lda(documents, 2, 5, ['en']);
// Use German.
result = lda(documents, 2, 5, ['de']);
// Use English + German.
result = lda(documents, 2, 5, ['en', 'de']);
```
To add a new language-specific stop-words list, create a file /lda/lib/stopwords_XX.js where XX is the id for the language. For example, a French stop-words list could be named "stopwords_fr.js". The contents of the file should follow the format of an [existing](https://github.com/primaryobjects/lda/blob/master/lib/stopwords_en.js) stop-words list. The format is, as follows:
```javascript
exports.stop_words = [
'cette',
'que',
'une',
'il'
];
```
## Setting a Random Seed
A specific random seed can be used to compute the same terms and probabilities during subsequent runs. You can specify the random seed, as follows:
```javascript
// Use the random seed 123.
result = lda(documents, 2, 5, null, null, null, 123);
```
## Author
Kory Becker
http://www.primaryobjects.com
Based on original javascript implementation
https://github.com/awaisathar/lda.js