MLI: An API for Distributed Machine Learning

MLI is an Application Programming Interface designed to address the challenges of building Machine Learn- ing algorithms in a distributed setting based on data-centric computing. Its primary goal is to simplify the development of high-performance, scalable, distributed algorithms. Our initial results show that, relative to existing systems, this interface can be used to build distributed implementations of a wide variety of common Machine Learning algorithms with minimal complexity and highly competitive performance and scalability

Scalable and distributed constrained low rank approximations

Low rank approximation is the problem of finding two low rank factors W and H such that the rank(WH) << rank(A) and A ≈ WH. These low rank factors W and H can be constrained for meaningful physical interpretation and referred as Constrained Low Rank Approximation (CLRA). Like most of the constrained optimization problem, performing CLRA can be computationally expensive than its unconstrained counterpart. A widely used CLRA is the Non-negative Matrix Factorization (NMF) which enforces non-negativity constraints in each of its low rank factors W and H. In this thesis, I focus on scalable/distributed CLRA algorithms for constraints such as boundedness and non-negativity for large real world matrices that includes text, High Definition (HD) video, social networks and recommender systems. First, I begin with the Bounded Matrix Low Rank Approximation (BMA) which imposes a lower and an upper bound on every element of the lower rank matrix. BMA is more challenging than NMF as it imposes bounds on the product WH rather than on each of the low rank factors W and H. For very large input matrices, we extend our BMA algorithm to Block BMA that can scale to a large number of processors. In applications, such as HD video, where the input matrix to be factored is extremely large, distributed computation is inevitable and the network communication becomes a major performance bottleneck. Towards this end, we propose a novel distributed Communication Avoiding NMF (CANMF) algorithm that communicates only the right low rank factor to its neighboring machine. Finally, a general distributed HPC- NMF framework that uses HPC techniques in communication intensive NMF operations and suitable for broader class of NMF algorithms.Ph.D

Parallelizing k-means with hadoop/mahout for big data analytics

This thesis was submitted for the degree of Master of Philosophy and awarded by Brunel University LondonThe rapid development of Internet and cloud computing technologies has led to explosive generation and processing of huge amounts of data. The ever increasing data volumes bring great values to societies, but in the meantime bring forward a number of challenges. Data mining techniques have been widely used in decision analysis in financial, medical, management, business and many other fields. However, how to analyse and mine valuable information from the massive data has become a crucial problem as the traditional methods are hardly to achieve high scalability in data processing. Recently, MapReduce has emerged into a major programming model in dealing with big data analytics. Apache Hadoop, which is an open-source implementation of MapReduce, has been widely taken up by the community. Hadoop facilitates the utilization of a large number of inexpensive commodity computers. In addition, Hadoop provides support in dealing with faults which is especially useful for long running jobs. Mahout is a new open-source project of Apache, providing a number of machine learning and data mining algorithms based on the Hadoop platform. As a machine learning technique, K-means has been widely used in data analytics through clustering. However, K-means experiences high overhead in computation when the size of data to be analysed is large. This thesis parallelizes K-means using the MapReduce model and implements a parallel K-means with Mahout on the Hadoop platform. The parallel K-means reduces the computation time significantly in comparison with the standard K-means in dealing with a large data set. In addition, this thesis further evaluates the impact of Hadoop parameters on the performance of the Hadoop framework