Thread overview
[Issue 2865] New: RandomCover not random.
Apr 20, 2009
d-bugmail
Apr 20, 2009
d-bugmail
May 13, 2009
David Simcha
Jul 06, 2009
Derek Parnell
Jul 09, 2009
Walter Bright
April 20, 2009
http://d.puremagic.com/issues/show_bug.cgi?id=2865

           Summary: RandomCover not random.
           Product: D
           Version: 2.029
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Phobos
        AssignedTo: bugzilla@digitalmars.com
        ReportedBy: dsimcha@yahoo.com


RandomCover is not actually random because the selection of the next element to visit goes up to index k - 2 instead of element k - 1, where k = _input.length - _alreadyChosen.

I'm assuming this was because someone forgot that the default bounds of uniform are [), not [].  Patch to follow momentarily.


-- 

April 20, 2009
http://d.puremagic.com/issues/show_bug.cgi?id=2865





------- Comment #1 from dsimcha@yahoo.com  2009-04-20 16:33 -------
Created an attachment (id=330)
 --> (http://d.puremagic.com/issues/attachment.cgi?id=330&action=view)
Fix.


-- 

May 13, 2009
http://d.puremagic.com/issues/show_bug.cgi?id=2865


David Simcha <dsimcha@yahoo.com> changed:

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




--- Comment #2 from David Simcha <dsimcha@yahoo.com>  2009-05-13 13:47:29 PDT ---
This is clearly fixed in 2.030 even though it's not noted in the changelog. The change was made in the relevant code, and RandomCover passes basic statistical tests for uniformity over the permutation space now.

Please update the changelog to reflect this.

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July 06, 2009
http://d.puremagic.com/issues/show_bug.cgi?id=2865


Andrei Alexandrescu <andrei@metalanguage.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |andrei@metalanguage.com




--- Comment #3 from Andrei Alexandrescu <andrei@metalanguage.com>  2009-07-06 10:17:26 PDT ---
Apologies. I'm not sure how this change escaped from the changelog, I diff and look at each file before the release.

Thanks for the patch!

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July 06, 2009
On Mon, 6 Jul 2009 17:17:27 +0000 (UTC), d-bugmail@puremagic.com wrote:

> I'm not sure how this change escaped from the changelog ...

May I suggest ... "manual process"?

-- 
Derek Parnell
Melbourne, Australia
skype: derek.j.parnell
July 09, 2009
http://d.puremagic.com/issues/show_bug.cgi?id=2865





--- Comment #4 from Walter Bright <bugzilla@digitalmars.com>  2009-07-09 02:55:08 PDT ---
Fixed dmd 2.031

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