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  1. Commons RNG
  2. RNG-81

NumberFactory to evenly sample all representable rationals between 0 and 1

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Details

    • Improvement
    • Status: Closed
    • Major
    • Resolution: Implemented
    • 1.3
    • 1.3
    • core
    • None

    Description

      Change the number factory methods for nextFloat and nextDouble

      Currently the methods use:

      • 23-bits of state from an int to create a float
      • 52-bits of state from a long to create a double

      This method produces output floating point numbers with the final bit of the mantissa set to 0. The methods can be changed to use 24-bits and 53-bits of state respectively.

      This will match the implementation in java.util.SplittableRandom.

      Benchmarking has shown no noticeable difference in speed.

      Note that this change modifies the output float to evenly sample all k/2^-24 dyadic rationals and the double to evenly sample all k/2^-53 dyadic rationals, i.e. the maximum number representable between 0 (inclusive) and 1.0 (exclusive).

       

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            aherbert Alex Herbert
            aherbert Alex Herbert
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