[PHP NlpTools](http://php-nlp-tools.com/)
=============

NlpTools is a set of php 5.3+ classes for beginner to
semi advanced natural language processing work.

Documentation
-------------

You can find documentation and code examples at the project's [homepage](http://php-nlp-tools.com/documentation/).

Contents
---------

### Classification Models ###

1. [Multinomial Naive Bayes](http://php-nlp-tools.com/documentation/bayesian-model.html)
2. [Maximum Entropy (Conditional Exponential model)](http://php-nlp-tools.com/documentation/maximum-entropy-model.html)

### Topic Modeling ###

Lda is still experimental and quite slow but it works. [See an example](http://php-nlp-tools.com/posts/introducing-latent-dirichlet-allocation.html).

1. [Latent Dirichlet Allocation](http://php-nlp-tools.com/documentation/api/#NlpTools/Models/Lda)

### Clustering ###

1. [K-Means](http://php-nlp-tools.com/documentation/clustering.html)
2. [Hierarchical Agglomerative Clustering](http://php-nlp-tools.com/documentation/clustering.html)
   * SingleLink
   * CompleteLink
   * GroupAverage

### Tokenizers ###

1. [WhitespaceTokenizer](http://php-nlp-tools.com/documentation/api/#NlpTools/Tokenizers/WhitespaceTokenizer)
2. [WhitespaceAndPunctuationTokenizer](http://php-nlp-tools.com/documentation/api/#NlpTools/Tokenizers/WhitespaceAndPunctuationTokenizer)
3. [PennTreebankTokenizer](http://php-nlp-tools.com/documentation/api/#NlpTools/Tokenizers/PennTreebankTokenizer)
4. [RegexTokenizer](http://php-nlp-tools.com/documentation/api/#NlpTools\Tokenizers\RegexTokenizer)
5. [ClassifierBasedTokenizer](http://php-nlp-tools.com/documentation/api/#NlpTools/Tokenizers/ClassifierBasedTokenizer)
   This tokenizer allows us to build a lot more complex tokenizers
   than the previous ones

### Documents ###

1. [TokensDocument](http://php-nlp-tools.com/documentation/api/#NlpTools/Documents/TokensDocument)
   represents a bag of words model for a document.
2. [WordDocument](http://php-nlp-tools.com/documentation/api/#NlpTools/Documents/WordDocument)
   represents a single word with the context of a larger document.
3. [TrainingDocument](http://php-nlp-tools.com/documentation/api/#NlpTools/Documents/TrainingDocument)
   represents a document whose class is known.
4. [TrainingSet](http://php-nlp-tools.com/documentation/api/#NlpTools/Documents/TrainingSet)
   a collection of TrainingDocuments

### Feature factories ###

1. [FunctionFeatures](http://php-nlp-tools.com/documentation/api/#NlpTools/FeatureFactories/FunctionFeatures)
   Allows the creation of a feature factory from a number of callables
2. [DataAsFeatures](http://php-nlp-tools.com/documentation/api/#NlpTools/FeatureFactories/DataAsFeatures)
   Simply return the data as features.

### Similarity ###

1. [Jaccard Index](http://php-nlp-tools.com/documentation/api/#NlpTools/Similarity/JaccardIndex)
2. [Cosine similarity](http://php-nlp-tools.com/documentation/api/#NlpTools/Similarity/CosineSimilarity)
3. [Simhash](http://php-nlp-tools.com/documentation/api/#NlpTools/Similarity/Simhash)
4. [Euclidean](http://php-nlp-tools.com/documentation/api/#NlpTools/Similarity/Euclidean)
5. [HammingDistance](http://php-nlp-tools.com/documentation/api/#NlpTools/Similarity/HammingDistance)

### Stemmers ###

1. [PorterStemmer](http://php-nlp-tools.com/documentation/api/#NlpTools/Stemmers/PorterStemmer)
2. [RegexStemmer](http://php-nlp-tools.com/documentation/api/#NlpTools/Stemmers/RegexStemmer)
3. [LancasterStemmer](http://php-nlp-tools.com/documentation/api/#NlpTools/Stemmers/LancasterStemmer)
4. [GreekStemmer](http://php-nlp-tools.com/documentation/api/#NlpTools/Stemmers/GreekStemmer)

### Optimizers (MaxEnt only) ###

1. [A gradient descent optimizer](http://php-nlp-tools.com/documentation/api/#NlpTools/Optimizers/MaxentGradientDescent)
   (written in php) for educational use.
   It is a simple implementation for anyone wanting to know a bit
   more about either GD or MaxEnt models
2. A fast (faster than nltk-scipy), parallel gradient descent
   optimizer written in [Go](http://golang.org/). This optimizer
   resides in another [repo](https://github.com/angeloskath/nlp-maxent-optimizer),
   it is used via the [external optimizer](http://php-nlp-tools.com/documentation/api/#NlpTools/Optimizers/ExternalMaxentOptimizer).
   TODO: At least write a readme for the optimizer written in Go.

### Other ###

1. Idf Inverse document frequency
2. Stop words
3. Language based normalizers
4. Classifier based transformation for creating flexible preprocessing pipelines