Experimental Parallel Algorithmics

    Institute for Advanced Computer Studies

    University of Maryland, College Park

    Faculty Director

      Joseph Já Já, (joseph@umiacs.umd.edu)

    Research Associates

      David A. Bader (dbader@umiacs.umd.edu)
      David R. Helman (helman@umiacs.umd.edu)

    Related Research

      NSF Grand Challenge Project for Land Cover Dynamics
      Larry S. Davis (lsd@umiacs.umd.edu)
      Algorithms Research
      High Performance Computing

    Focus:

    A fundamental problem in parallel computing is to design high-level, architecture independent, algorithms that execute efficiently on general purpose parallel machines. The purpose of this project is to advance our understanding of the main factors required for designing practical parallel algorithms and to develop techniques and data sets for experimentally validating the results. As a byproduct, we are developing portable parallel programs and data sets for a number of specific important problems arising in combinatorial computing and image processing.
      Clusters of SMPs
      Combinatorial Computing
      Image Processing

    Clusters of SMPs

    We describe a methodology for developing high performance programs running on clusters of SMP nodes. Our methodology is based on a small kernel (SIMPLE) of collective communication primitives that make efficient use of the hybrid shared and message passing environment.

    Recent Publications

      SIMPLE: A Methodology for Programming High Performance Algorithms on Clusters of Symmetric Multiprocessors (SMPs)
      Sorting on Clusters of SMPs

    Combinatorial Computing

    We are addressing a number of basic combinatorial computations that are commonly needed in various large scale applications. One such computation is sorting, a problem that has been studied extensively in the literature because of its many important applications and because of its intrinsic theoretical significance. Our research has produced the fastest known high-level, practical algorithms for many combinatorial problems such as sorting, personalized communication, selection, list ranking, and data redistribution, on general purpose parallel machines.

    Recent Publications

      Designing Practical Efficient Algorithms for Symmetric Multiprocessors
      Prefix Computations on Symmetric Multiprocessors
      A Randomized Parallel Sorting Algorithm With an Experimental Study
      A New Deterministic Parallel Sorting Algorithm With an Experimental Evaluation
      Parallel Algorithms for Personalized Communication and Sorting With an Experimental Study (Extended Abstract)
      Practical Parallel Algorithms for Personalized Communication and Integer Sorting
      Practical Parallel Algorithms for Dynamic Data Redistribution, Median Finding, and Selection
      The Block Distributed Memory Model

    Image Processing

    Image processing applications are well-suited to high performance computing techniques for several reasons: uniform grid layouts, spatial locality, and highly regular kernels. Images used for analysis are produced from a variety of applications, for example, remote sensing, image understanding, face recognition, detection of surface defects in industrial manufacturing, military target recognition, etc. Some of the processing is low-level, such as image calibration or enhancement, while other analysis is intermediate- or high-level, such as segmenting an image into objects or regions and classifying each. We have developed a high performance suite of practical algorithms for image processing that seem to outperform all other known implementations on the same platforms.

    Recent Publications

      Parallel Algorithms for Image Enhancement and Segmentation by Region Growing with an Experimental Study
      Parallel Algorithms for Image Histogramming and Connected Components with an Experimental Study
      Efficient Image Processing Algorithms on the Scan Line Array Processor
      Scalable Parallel Algorithms for Texture Synthesis and Compression

    Experimental Data Sets

    dbader@umiacs.umd.edu