rfc:rng_fixes

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rfc:rng_fixes [2016/06/14 14:58] – leighrfc:rng_fixes [2016/06/16 18:48] – leigh
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   * Platform-specific outputs   * Platform-specific outputs
   * Poor scaling of bounded outputs   * Poor scaling of bounded outputs
 +
 +This would also give a performance benefit to heavy users of the functions, as <php>mt_rand()</php> is very slow.
  
 == Fix mt_rand() implementation == == Fix mt_rand() implementation ==
 The implementation of <php>mt_rand()</php> in PHP contains a typo that makes it generate a different sequence of numbers to the original mt19937 implementation. [[https://bugs.php.net/bug.php?id=71152|See bug #71152]] The implementation of <php>mt_rand()</php> in PHP contains a typo that makes it generate a different sequence of numbers to the original mt19937 implementation. [[https://bugs.php.net/bug.php?id=71152|See bug #71152]]
  
-It is not known if the period or the quality of the output from the RNG is negatively affected due to this typo.+It is not known if the period of the RNG is negatively affected due to this typo, although statistical analysis suggests that the quality of the output is unaffected.
  
 As <php>mt_rand()</php> can be seeded for repeatable sequences the current implementation makes it incompatible with other systems that do use correct implementations. However fixing it also means that the sequence generated for a given seed in PHP will also now be different. As <php>mt_rand()</php> can be seeded for repeatable sequences the current implementation makes it incompatible with other systems that do use correct implementations. However fixing it also means that the sequence generated for a given seed in PHP will also now be different.
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 ===== Proposed Voting Choices ===== ===== Proposed Voting Choices =====
-This will be an all or nothing vote (after discussion), and as the changes are functional, will require a 50%+1 majority to pass.+Individual votes will be held for the remaining proposals, and since minor BC breaks are introduced they will require a 2/3 majority to pass.
  
 ===== Patches and Tests ===== ===== Patches and Tests =====
rfc/rng_fixes.txt · Last modified: 2017/09/22 13:28 by 127.0.0.1

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