MADlib graduated to an Apache Top Level Project on 7/19/17.  Read the press release. 

MADlib® is an open-source library for scalable in-database analytics.

It provides data-parallel implementations of mathematical, statistical,

graph and machine learning methods for structured and unstructured data.

Quick Start Guides

• Installation Guide
• Quick Start Guide for Users
• Quick Start Guide for Developers

General Information

• MADlib website 
• Jupyter notebooks for many MADlib algorithms
• Greenplum database YouTube channel with MADlib content
• Module and algorithm documentation
• FAQ

Developer Documentation

• Source code repo
• Contribution Guidelines
• Documentation Guide (Doxygen)
• Ideas for contribution 
• Algorithm technical design document

Architecture

• Architecture
• Module Anatomy

Release Notes

• Release notes
• Downloads

Licensing

License information regarding MADlib and included third-party libraries can be found inside the license directory.  ASF licensing guidance for MADlib pertaining to its pre-Apache history as an open source project with BSD licensing is described here.

Papers

• MAD Skills : New Analysis Practices for Big Data (VLDB 2009)
• Hybrid In-Database Inference for Declarative Information Extraction (SIGMOD 2011)
• Towards a Unified Architecture for In-Database Analytics (SIGMOD 2012)
• The MADlib Analytics Library or MAD Skills, the SQL (VLDB 2012)

Related Software

• PivotalR - lets the user run the functions of the open-source big-data machine learning package MADlib directly from R.

• PyMADlib  - a nascent Python wrapper for MADlib, which brings you the power and flexibility of python with the number crunching power of MADlib.