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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: ada.synchronous_barriers incomplete?
Date: Tue, 1 May 2018 14:34:15 +0200
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Date: 2018-05-01T14:34:15+02:00
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On 2018-05-01 13:26, hnptz@yahoo.de wrote:
> The rationale_2102 says: "There are many situations where the release of N tasks is required to execute an algorithm in parallel". My question is how to stop N-1 tasks after one of the N tasks has found the required solution before all other N-1 taks?

An atomic Boolean set true by the first task reaching the solution? 
Other task can periodically check the value.

Or it could be the asynchronous transfer of control if the tasks do only 
computations:

    task body Worker is
    begin
       select
          Ready.Wait; -- Protected object implementation of an event
       then abort
          loop -- Incredibly long computations
             ...
             exit when Converged;
             ...
          end loop;
          Ready.Signal; -- I am the first!
       end select;
    end Worker;

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de