Uzi Vishkin

- Professor, Univ. of Md Institute for Advanced Computer Studies (UMIACS) and
Department of Electrical and Computer Engineering
- Affiliate Professor, Department of Computer Science. See, the Algorithms and Theory Group

• D.Sc., Computer Science, Technion - Israel Institute of Technology (Haifa, Israel), 1981
• M.Sc., Mathematics, Hebrew University (Jerusalem, Israel), 1975
• B.Sc., Mathematics, Hebrew University (Jerusalem, Israel), 1974

Organization

• Fellow, Association for Computing Machinery (ACM), 1996. Citation.
• Highly Cited Researcher, Computer Science, Thompson ISI, 2003.

• Parallelism in computing
  • Parallel algorithmics
  • The interplay between parallel computer systems (thread-level and processor-level parallelism) and algorithms (parallel and serial)
  • Is PRAM algorithmics implementable? A PRAM-On-Chip Vision...
• Design and analysis of algorithms.
• Parallel computer architecture.

  The premise that inspired his work in the last few years on the PRAM-On-Chip framework has been: Were the architecture component of PRAM-On-Chip feasible in the 1990s, its parallel programming component would have become the mainstream standard.

  In 1979 Uzi Vishkin identified the issue of parallel algorithms/programmability as the most critical component in developing a successful general-purpose parallel computer architecture. It simply did not look practical to proceed with building parallel computers before establishing a first satisfactory draft of its specifications. Such "specs" had to include how to think about programming the computer to be built.

  Many, including Uzi Vishkin, spent the next 15-20 years on parallel algorithmics. In fact, during the 1980s and the early 1990s, quite a few very talented computer science researchers worked on the following wider problem: Seek the "ultimate" parallel programming model that will allow easy expression of parallel algorithms and their programs in the model, as well as validation of the model by algorithmic paradigms and solutions for as many problems as possible. In this fierce "battle of ideas", the one approach that has beaten all its competitors by a truly wide margin was the PRAM approach. As early as 1988, standard algorithms textbooks started including significant chapters on PRAM algorithms, and as the above premise suggests, PRAM algorithms were on their way to become standard computer science know-how that every computer science graduate must command and the basis for standard parallel programming. However, multi-chip multi-processing architectures provided the only form of multi-processing available in the 1990s. They required high coordination overhead, which prevented PRAM algorithms from providing an effective abstraction for them. As a result, it became common wisdom that "PRAM algorithms are unrealistics", leading later editions of some textbooks to remove their PRAM chapters.

  The good news are that the PRAM-On-Chip effort is finally establishing that it is becoming feasible to build a parallel computer that can be effectively programmed by a PRAM-like language.

  From today's perspective, the prospects for making the PRAM approach a standard for parallel algorithms and programming look pretty good: (i) "Darwin has already spoken" - see the natural selection that already happened in what was called above the battle of ideas, and (ii) The inclusion of significant PRAM chapters in standard textbooks, before concerns about implementability prevailed; but these concernes are becoming irrelevant as the PRAM-On-Chip progresses.

  The optimistic tone above should not hide the fact that a significant research effort is still underway.

• Pattern matching.
• Theory of computing. In fact, the theory-driven PRAM-On-Chip effort aspires to provide a nice example where a forward looking theory-driven approach has practical impact.

• List of Publications
• Several recent technical reports and class notes available for download

• PRAM-On-Chip - A Desktop Supercomputer

• NEW: On-Line Tutorial .

• Organizer and presenter, Tutorial on "How to Think Algorithmically in Parallel", Seattle, WA, Sunday, June 17, 2007, held in conjunction with the 21st ACM International Conference on Supercomputing (ICS).

• Organizer, Workshop on Parallelism in Algorithms and Architecture, May 12, 2006
• Program Chair, ACM SPAA 2006
  From the scope statement for SPAA 2006:

  A renaissance of parallel computing research is on the horizon since: (i) chip multi-cores are the wave of the future for all major hardware vendors, (ii) since 2003 clock frequency of CPUs is hardly advancing any more, (iii) the 6-decade quest for an easy-to-program parallel architecture paradigm is yet to provide a competitive alternative to the serial paradigm. Contributed papers on algorithmics, software and/or hardware that address this emerging renaissance are particularly welcome for SPAA 2006.

Talks

• For more talks see the PRAM-On-Chip home page

• Spring 2008: HONR219A Towards a New Era of Desktop Supercomputing. Subtitle: How will computer programmers have to think by the time you graduate?
• Spring 2007: ENEE759K/CMSC751 Parallel Algorithmics.
• Fall 2005: ENEE641 Mathematical Foundations for Computer Engineering.

Mailing Address:

Uzi Vishkin

University of Maryland Institute for Advanced Computer Studies (UMIACS)

A.V. Williams Building

College Park, MD 20742-3251

Phone: (301) 405-6763

email: x at umd.edu, where x is the last name