Recommender - A C library for product recommendations/suggestions using collaborative filtering (CF).
Accord-Framework -The Accord.NET Framework is a complete framework for building machine learning, computer vision, computer audition, signal processing and statistical applications.
Computer Vision
CCV - C-based/Cached/Core Computer Vision Library, A Modern Computer Vision Library
C++ Computer Vision
OpenCV - OpenCV has C++, C, Python, Java and MATLAB interfaces and supports Windows, Linux, Android and Mac OS.
DLib - DLib has C++ and Python interfaces for face detection and training general object detectors.
EBLearn - Eblearn is an object-oriented C++ library that implements various machine learning models *
CRF++ - Open source implementation of Conditional Random Fields (CRFs) for segmenting/labeling sequential data & other Natural Language Processing tasks.
Speech Recognition
Kaldi - Kaldi is a toolkit for speech recognition written in C++ and licensed under the Apache License v2.0. Kaldi is intended for use by speech recognition researchers.
Sequence Analysis
ToPS - This is an objected-oriented framework that facilitates the integration of probabilistic models for sequences over a user defined alphabet.
Clojure Natural Language Processing
Clojure-openNLP - Natural Language Processing in Clojure (opennlp)
Infections-clj - Rails-like inflection library for Clojure and ClojureScript
hopfield-networks - Hopfield Networks for unsupervised learning in Haskell.
Java Natural Language Processing
CoreNLP - Stanford CoreNLP provides a set of natural language analysis tools which can take raw English language text input and give the base forms of words
Stanford Parser - A natural language parser is a program that works out the grammatical structure of sentences
Stanford Word Segmenter - Tokenization of raw text is a standard pre-processing step for many NLP tasks.
Tregex, Tsurgeon and Semgrex - Tregex is a utility for matching patterns in trees, based on tree relationships and regular expression matches on nodes (the name is short for "tree regular expressions").
Stanford English Tokenizer - Stanford Phrasal is a state-of-the-art statistical phrase-based machine translation system, written in Java.
Stanford Tokens Regex - A tokenizer divides text into a sequence of tokens, which roughly correspond to "words"
Stanford Temporal Tagger - SUTime is a library for recognizing and normalizing time expressions.
Stanford SPIED - Learning entities from unlabeled text starting with seed sets using patterns in an iterative fashion
Stanford Topic Modeling Toolbox - Topic modeling tools to social scientists and others who wish to perform analysis on datasets
Twitter Text Java - A Java implementation of Twitter's text processing library
MALLET - A Java-based package for statistical natural language processing, document classification, clustering, topic modeling, information extraction, and other machine learning applications to text.
OpenNLP - a machine learning based toolkit for the processing of natural language text.
LingPipe - A tool kit for processing text using computational linguistics.
ClearTK - ClearTK provides a framework for developing statistical natural language processing (NLP) components in Java and is built on top of Apache UIMA.
Apache cTAKES - Apache clinical Text Analysis and Knowledge Extraction System (cTAKES) is an open-source natural language processing system for information extraction from electronic medical record clinical free-text.
General-Purpose Machine Learning
JSAT - Numerous Machine Learning algoirhtms for classification, regresion, and clustering.
cephes - Cephes mathematical functions library, wrapped for Torch. Provides and wraps the 180+ special mathematical functions from the Cephes mathematical library, developed by Stephen L. Moshier. It is used, among many other places, at the heart of SciPy.
nngraph - This package provides graphical computation for nn library in Torch7.
nnx - A completely unstable and experimental package that extends Torch's builtin nn library
optim - An optimization library for Torch. SGD, Adagrad, Conjugate-Gradient, LBFGS, RProp and more.
unsup - A package for unsupervised learning in Torch. Provides modules that are compatible with nn (LinearPsd, ConvPsd, AutoEncoder, ...), and self-contained algorithms (k-means, PCA).
vowpalwabbit - An old vowpalwabbit interface to torch.
OpenGM - OpenGM is a C++ library for graphical modeling, and inference. The Lua bindings provide a simple way of describing graphs, from Lua, and then optimizing them with OpenGM.
sphagetti - Spaghetti (sparse linear) module for torch7 by @MichaelMathieu
LuaSHKit - A lua wrapper around the Locality sensitive hashing library SHKit
kernel smoothing - KNN, kernel-weighted average, local linear regression smoothers
imgraph - An image/graph library for Torch. This package provides routines to construct graphs on images, segment them, build trees out of them, and convert them back to images.
videograph - A video/graph library for Torch. This package provides routines to construct graphs on videos, segment them, build trees out of them, and convert them back to videos.
saliency - code and tools around integral images. A library for finding interest points based on fast integral histograms.
stitch - allows us to use hugin to stitch images and apply same stitching to a video sequence
sfm - A bundle adjustment/structure from motion package
fex - A package for feature extraction in Torch. Provides SIFT and dSIFT modules.
OverFeat - A state-of-the-art generic dense feature extractor
Curvelets - The Curvelet transform is a higher dimensional generalization of the Wavelet transform designed to represent images at different scales and different angles.
t-Distributed Stochastic Neighbor Embedding - t-Distributed Stochastic Neighbor Embedding (t-SNE) is a (prize-winning) technique for dimensionality reduction that is particularly well suited for the visualization of high-dimensional datasets.
Spider - The spider is intended to be a complete object orientated environment for machine learning in Matlab.
Pattern Recognition and Machine Learning - This package contains the matlab implementation of the algorithms described in the book Pattern Recognition and Machine Learning by C. Bishop.
Data Analysis / Data Visualization
matlab_gbl - MatlabBGL is a Matlab package for working with graphs.
gamic - Efficient pure-Matlab implementations of graph algorithms to complement MatlabBGL's mex functions.
.NET Computer Vision
OpenCVDotNet - A wrapper for the OpenCV project to be used with .NET applications.
Emgu CV - Cross platform wrapper of OpenCV which can be compiled in Mono to e run on Windows, Linus, Mac OS X, iOS, and Android.
Natural Language Processing
Stanford.NLP for .NET - A full port of Stanford NLP packages to .NET and also available precompiled as a NuGet package.
General-Purpose Machine Learning
Accord.MachineLearning - Support Vector Machines, Decision Trees, Naive Bayesian models, K-means, Gaussian Mixture models and general algorithms such as Ransac, Cross-validation and Grid-Search for machine-learning applications. This package is part of the Accord.NET Framework.
Vulpes - Deep belief and deep learning implementation written in F# and leverages CUDA GPU execution with Alea.cuBase.
Encog - An advanced neural network and machine learning framework. Encog contains classes to create a wide variety of networks, as well as support classes to normalize and process data for these neural networks. Encog trains using multithreaded resilient propagation. Encog can also make use of a GPU to further speed processing time. A GUI based workbench is also provided to help model and train neural networks.
Neural Network Designer - DBMS management system and designer for neural networks. The designer application is developed using WPF, and is a user interface which allows you to design your neural network, query the network, create and configure chat bots that are capable of asking questions and learning from your feed back. The chat bots can even scrape the internet for information to return in their output as well as to use for learning.
Data Analysis / Data Visualization
numl - numl is a machine learning library intended to ease the use of using standard modeling techniques for both prediction and clustering.
Math.NET Numerics - Numerical foundation of the Math.NET project, aiming to provide methods and algorithms for numerical computations in science, engineering and every day use. Supports .Net 4.0, .Net 3.5 and Mono on Windows, Linux and Mac; Silverlight 5, WindowsPhone/SL 8, WindowsPhone 8.1 and Windows 8 with PCL Portable Profiles 47 and 344; Android/iOS with Xamarin.
Sho - Sho is an interactive environment for data analysis and scientific computing that lets you seamlessly connect scripts (in IronPython) with compiled code (in .NET) to enable fast and flexible prototyping. The environment includes powerful and efficient libraries for linear algebra as well as data visualization that can be used from any .NET language, as well as a feature-rich interactive shell for rapid development.
Python Computer Vision
SimpleCV - An open source computer vision framework that gives access to several high-powered computer vision libraries, such as OpenCV. Written on Python and runs on Mac, Windows, and Ubuntu Linux.
Natural Language Processing
NLTK - A leading platform for building Python programs to work with human language data.
Pattern - A web mining module for the Python programming language. It has tools for natural language processing, machine learning, among others.
Quepy - A python framework to transform natural language questions to queries in a database query language
TextBlob - Providing a consistent API for diving into common natural language processing (NLP) tasks. Stands on the giant shoulders of NLTK and Pattern, and plays nicely with both.
YAlign - A sentence aligner, a friendly tool for extracting parallel sentences from comparable corpora.
scikit-learn - A Python module for machine learning built on top of SciPy.
SimpleAI Python implementation of many of the artificial intelligence algorithms described on the book "Artificial Intelligence, a Modern Approach". It focuses on providing an easy to use, well documented and tested library.
astroML - Machine Learning and Data Mining for Astronomy.
graphlab-create - A library with various machine learning models (regression, clustering, recommender systems, graph analytics, etc.) implemented on top of a disk-backed DataFrame.
Caffe - A deep learning framework developed with cleanliness, readability, and speed in mind.
breze - Theano based library for deep and recurrent neural networks
pyhsmm - library for approximate unsupervised inference in Bayesian Hidden Markov Models (HMMs) and explicit-duration Hidden semi-Markov Models (HSMMs), focusing on the Bayesian Nonparametric extensions, the HDP-HMM and HDP-HSMM, mostly with weak-limit approximations.
mrjob - A library to let Python program run on Hadoop.
SKLL - A wrapper around scikit-learn that makes it simpler to conduct experiments.
Spearmint - Spearmint is a package to perform Bayesian optimization according to the algorithms outlined in the paper: Practical Bayesian Optimization of Machine Learning Algorithms. Jasper Snoek, Hugo Larochelle and Ryan P. Adams. Advances in Neural Information Processing Systems, 2012.
Data Analysis / Data Visualization
SciPy - A Python-based ecosystem of open-source software for mathematics, science, and engineering.
NumPy - A fundamental package for scientific computing with Python.
Numba - Python JIT (just in time) complier to LLVM aimed at scientific Python by the developers of Cython and NumPy.
NetworkX - A high-productivity software for complex networks.
Pandas - A library providing high-performance, easy-to-use data structures and data analysis tools.
Open Mining - Business Intelligence (BI) in Python (Pandas web interface)
group-lasso - Some experiments with the coordinate descent algorithm used in the (Sparse) Group Lasso model
jProcessing - Kanji / Hiragana / Katakana to Romaji Converter. Edict Dictionary & parallel sentences Search. Sentence Similarity between two JP Sentences. Sentiment Analysis of Japanese Text. Run Cabocha(ISO--8859-1 configured) in Python.
mne-python-notebooks - IPython notebooks for EEG/MEG data processing using mne-python
Treat - Text REtrieval and Annotation Toolkit, definitely the most comprehensive toolkit I’ve encountered so far for Ruby
Ruby Linguistics - Linguistics is a framework for building linguistic utilities for Ruby objects in any language. It includes a generic language-independant front end, a module for mapping language codes into language names, and a module which contains various English-language utilities.
Listof - Community based data collection, packed in gem. Get list of pretty much anything (stop words, countries, non words) in txt, json or hash. Demo/Search for a list
R General-Purpose Machine Learning
h2o - A framework for fast, parallel, and distributed machine learning algorithms at scale -- Deeplearning, Random forests, GBM, KMeans, PCA, GLM
elasticnet - elasticnet: Elastic-Net for Sparse Estimation and Sparse PCA
ElemStatLearn - ElemStatLearn: Data sets, functions and examples from the book: "The Elements of Statistical Learning, Data Mining, Inference, and Prediction" by Trevor Hastie, Robert Tibshirani and Jerome Friedman
evtree - evtree: Evolutionary Learning of Globally Optimal Trees
frbs - frbs: Fuzzy Rule-based Systems for Classification and Regression Tasks
GAMBoost - GAMBoost: Generalized linear and additive models by likelihood based boosting
gamboostLSS - gamboostLSS: Boosting Methods for GAMLSS
ggplot2 - A data visualization package based on the grammar of graphics.
Scala Natural Language Processing
ScalaNLP - ScalaNLP is a suite of machine learning and numerical computing libraries.
Breeze - Breeze is a numerical processing library for Scala.
Chalk - Chalk is a natural language processing library.
FACTORIE - FACTORIE is a toolkit for deployable probabilistic modeling, implemented as a software library in Scala. It provides its users with a succinct language for creating relational factor graphs, estimating parameters and performing inference.