http://d.puremagic.com/issues/show_bug.cgi?id=2977

           Summary: std.random.unpredictableSeed() should use thread ID
                    somewhere
           Product: D
           Version: 2.030
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Phobos
        AssignedTo: bugzilla@digitalmars.com
        ReportedBy: dsimcha@yahoo.com


uint unpredictableSeed()
{
    static bool seeded;
    static MinstdRand0 rand;
    if (!seeded) {
        rand.seed(getpid ^ cast(uint)getUTCtime);
        seeded = true;
    }
    rand.popFront;
    return cast(uint) (getUTCtime ^ rand.front);
}

If called from multiple threads at exactly the same time, unpredictableSeed gives every thread the same seed.  This is annoying when running the same monte carlo simulation simultaneously in multiple threads, since I tend to spawn all of the threads at exactly the same time.  Something like:

(getpid + cast(uint) Thread.getThis) ^ cast(uint) getUTCtime

might work well.

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Andrei Alexandrescu <andrei@metalanguage.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
                 CC|                            |andrei@metalanguage.com
         AssignedTo|nobody@puremagic.com        |andrei@metalanguage.com


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David Simcha <dsimcha@yahoo.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


--- Comment #1 from David Simcha <dsimcha@yahoo.com> 2009-12-01 06:21:29 PST ---
Fixed SVN.

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Walter Bright <bugzilla@digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bugzilla@digitalmars.com


--- Comment #2 from Walter Bright <bugzilla@digitalmars.com> 2009-12-06 00:50:37 PST ---
Fixed dmd 2.037

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