Source

Naive Bayes#

Probability-based classifier that uses Bayes' Theorem and the strong assumption that all features are independent. In practice, the independent assumption tends to work out most of the time despite most features being correlated in the real world. This particular implementation is based on a multinomial (categorical) distribution of input features.

Note: Each partial train has the overhead of recomputing the probability mass function for each feature per class. As such, it is better to train with fewer but larger training sets.

Interfaces: Estimator, Learner, Online, Probabilistic, Persistable

Data Type Compatibility: Categorical

Parameters#

# Param Default Type Description
1 alpha 1.0 float The amount of additive (Laplace/Lidstone) smoothing applied to the probabilities.
2 priors Auto array The class prior probabilities as an associative array with class labels as keys and the prior probabilities as values.

Additional Methods#

Return the class prior probabilities:

public priors() : array

Return the counts for each category per class:

public counts() : array

Example#

use Rubix\ML\Classifiers\NaiveBayes;

$estimator = new NaiveBayes(2.5, [
    'spam' => 0.3,
    'not spam' => 0.7,
]);