Here are 2 papers from VLDB that include references to MADlib, in case of interest:
In-RDBMS Hardware Acceleration of Advanced Analytics http://www.vldb.org/pvldb/vol11/p1317-mahajan.pdf Proceedings of the VLDB Endowment, Vol. 11, No. 11 A Comparative Evaluation of Systems for Scalable Linear Algebra-based Analytics http://www.vldb.org/pvldb/vol11/p2168-thomas.pdf Proceedings of the VLDB Endowment, Vol. 11, No. 13 Frank
