Guides

In-depth reference documentation for the classifier gem.

Choosing a Classifier

Compare classifiers and pick the right one for your use case

Classifier Comparison

Compare all classifiers side-by-side to choose the right one for your use case.

classifier vs classifier-reborn

A fact-checked comparison of the classifier gem and the classifier-reborn fork, with release dates, feature support, and maintenance status verified on 2026-08-15.

Bayesian Classifier

Naive Bayes classification for categorizing text

Bayes Basics

Understand how the Bayesian classifier works and when to use it.

LSI (Semantic Analysis)

Latent Semantic Indexing for semantic search and similarity

LSI Basics

Learn Latent Semantic Indexing for semantic search and document similarity.

LSI Advanced

Incremental LSI, SVD tuning, and advanced patterns for high-performance semantic indexing.

k-Nearest Neighbors

Instance-based classification with interpretable results

kNN Basics

Instance-based classification with k-Nearest Neighbors for interpretable results.

TF-IDF Vectorizer

Transform text into weighted feature vectors

TF-IDF Basics

Transform text into weighted feature vectors with Term Frequency-Inverse Document Frequency.

Logistic Regression

Well-calibrated probabilities with interpretable feature weights

Logistic Regression Basics

Learn how the Logistic Regression classifier works for accurate, well-calibrated text classification.

Persistence

Save and load trained classifiers with pluggable backends

Persistence Framework

Save and load classifiers with pluggable storage backends.