From: mailbox@dmitry-kazakov.de   
      
   On Sun, 03 Dec 2006 13:09:50 GMT, Thuan Seah Tan wrote:   
      
   >     I wonder for a multiagent system simulating traffic flow where each   
   > vehicle is an agent, is it common to have a thread for each agent? Having a   
   > thread for each agent doesn't seem to be a good idea if we are looking at   
   > large numbers vehicle say >100 am I right to assume so? How do people using   
   > implement such a system then? Hope someone can advice me on this. Thanks in   
   > advance.   
      
   That depends on the environment you are using. Using Ada you usually have   
   an option not to map the tasks to OS threads/processes. In that case the   
   language run-time library schedules tasks without OS intervention. This   
   would make it possible to schedule far more than just 100 tasks.   
      
   In concrete case of traffic simulation, you likely wouldn't wish to use   
   preemptively scheduled tasks at all. Because you need to be sure that all   
   agents update their state within some time slice. Otherwise the simulation   
   would look as if car drivers suffered random frequent blackouts.   
      
   Concurrency would bring you nothing here. At the end of each time slice you   
   will need to resynchronize all tasks running the agents anyway. So it were   
   just an unnecessary overhead. In a situation where you had a natively   
   parallel system with many CPU, you indeed would like to distribute groups   
   of agents across the system partitions to better use computational   
   resources. But in each partition all agents would be still driven by one   
   task.   
      
   --   
   Regards,   
   Dmitry A. Kazakov   
   http://www.dmitry-kazakov.de   
      
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