Jamboree

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Jamboree algorithm,
a parallelized version of the Scout search algorithm. Similar to the Young Brothers Wait Concept, the idea is that all of the testing of any child that is not the first one, is done in parallel, and any tests that fail are sequentially valued. Jamboree search was introduced by Bradley Kuszmaul in his 1994 thesis Synchronized MIMD Computing .

Jamboree was used in the massive parallel chess programs StarTech and *Socrates. It sequentialize full-window searches for values, because, while their authors are willing to take a chance that an empty window search will be squandered work, they are not willing to take the chance that a full-window search (which does not prune very much) will be squandered work.

Pseudo Code

int jamboree(CNode n, int α, int β) {
   if (n is leaf) return static_eval(n);
   c[] = the childen of n;
   b = -jamboree(c[0], -β, -α); 
   if (b >= β) return b;
   if (b >  α) α = b;
   In Parallel: for (i=1; i < |c[]|; i++) {
      s = -jamboree(c[i], -α - 1, -α);
      if (s >  b) b = s;
      if (s >= β) abort_and_return s;
      if (s >  α) {
          /* Wait for completion of all previous iterations of the parallel loop */
          s = -jamboree(c[i], -β, -α);
          if (s >= β) abort_and_return s;
          if (s >  α) α = s;
          if (s >  b) b = s;
      }
      /* Note the completion of the ith iteration of the parallel loop */
   }
   return b;
}

See also

• ABDADA
• NegaScout
• Parallel Alpha-Beta in Cilk
• Scout
• *Socrates
• StarTech
• Young Brothers Wait Concept

Publications

• Bradley Kuszmaul (1994). Synchronized MIMD Computing. Ph. D. thesis, Department of Electrical Engineering and Computer Science, MIT, pdf
• Chris Joerg, Bradley Kuszmaul (1994). Massively Parallel Chess. Proceedings of the Third DIMACS Parallel Implementation Challenge, pdf
• Bradley Kuszmaul (1995). The StarTech Massively Parallel Chess Program. ICCA Journal, Vol. 18, No. 1, pdf
• Chris Joerg (1996). The Cilk System for Parallel Multithreaded Computing. Ph. D. thesis, Department of Electrical Engineering and Computer Science, MIT, pdf

External Links

• Jamboree (Scouting) from Wikipedia
• World Scout Jamboree from Wikipedia
• Robert Baden-Powell, 1st Baron Baden-Powell from Wikipedia
• Jamborees History / World Jamboree / World Events / Events / Information & Events / Home - World Organization of the Scout Movement
• Urszula Dudziak with Michał Urbaniak - Papaya/Young Pale Man, Warsaw Jamboree Jazz Festival 1991, YouTube Video

feat. Zbgniew Jakubek, Adam Wendt, Bernard Maseli, Marek Blaszczyk, Krystof Zawdzki

References

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