Author belopolsky
Recipients BreamoreBoy, aconrad, belopolsky, larry, mark.dickinson, python-dev, r.david.murray, tbarbugli, tim.peters, trcarden, vivanov, vstinner
Date 2015-09-04.22:43:50
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Message-id <1441406630.48.0.363736737577.issue23517@psf.upfronthosting.co.za>
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> By the way, why does Python use ROUND_HALF_EVEN for round()?

ROUND_HALF_EVEN does not introduce statistical bias in your floating point data.  With this choice a randomly chosen decimal has an equal chance of being rounded up or down.  I think one can prove the same for a binary float being converted to a decimal with a fixed number of places after dot.  The builtin round() is a unique beast and I would have to ask Mark to know what its statistical properties are, but in general round-half-to-even is justified by the desire of not introducing a statistical bias and I don't think the natural asymmetry of the time line matters in this argument.
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Date User Action Args
2015-09-04 22:43:50belopolskysetrecipients: + belopolsky, tim.peters, mark.dickinson, vstinner, larry, r.david.murray, aconrad, BreamoreBoy, vivanov, python-dev, tbarbugli, trcarden
2015-09-04 22:43:50belopolskysetmessageid: <1441406630.48.0.363736737577.issue23517@psf.upfronthosting.co.za>
2015-09-04 22:43:50belopolskylinkissue23517 messages
2015-09-04 22:43:50belopolskycreate