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Re: python implementation of a new integer encoding algorithm.

References <e45a71b2-7ec0-4c7d-88ae-c48aebe154b7@googlegroups.com> <54E34C68.6040700@davea.name> <mailman.18785.1424183690.18130.python-list@python.org> <65b209a0-33fc-4c1f-8af6-de3a4626623c@googlegroups.com> <54E49995.6040403@davea.name>
Date 2015-02-19 01:16 +1100
Subject Re: python implementation of a new integer encoding algorithm.
From Chris Angelico <rosuav@gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.18820.1424268970.18130.python-list@python.org> (permalink)

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On Thu, Feb 19, 2015 at 12:54 AM, Dave Angel <davea@davea.name> wrote:
>>> I've tried to read through the original algorithm description, but I'm
>>> not entirely sure: How many payload bits per transmitted byte does it
>>> actually achieve?
>>
>>
>> I don't think that payload bits per byte makes sense in this concept.
>>
>
> Correct.  Presumably one means average payload bits per byte.
>
> First one would have to define what the "standard" unencoded variable length
> integer format was.  Then one could call that size the payload size.  Then,
> in order to compute an average, one would have to specify an expected, or
> target distribution of values.  One then compares and averages the payload
> size for each typical value with the encoded size.

Average, or separately for different ranges. Alternatively, identify
which ranges of numbers can be encoded with how many bytes. For
instance, if you have a varlen length (in bytes) followed by that many
packed bytes, you would have:

2: up to 1<<8-1
3: up to 1<<16-1
4: up to 1<<24-1
...
128: up to 1<<1016-1
130: up to 1<<1024-1
131: up to 1<<1032-1
etc

Using varlen directly gives:

1: up to 1<<7-1
2: up to 1<<14-1
3: up to 1<<21-1
etc

So if your number is around about 1<<20, you know it's going to take 3
bytes to encode as varlen, or 4 to encode with the meta-length. Easy
comparisons.

I'm not sure how this algorithm compares, because it's extremely clever.

ChrisA

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python implementation of a new integer encoding algorithm. janhein.vanderburg@gmail.com - 2015-02-17 03:22 -0800
  Re: python implementation of a new integer encoding algorithm. Chris Angelico <rosuav@gmail.com> - 2015-02-18 00:16 +1100
    Re: python implementation of a new integer encoding algorithm. janhein.vanderburg@gmail.com - 2015-02-18 00:55 -0800
      Re: python implementation of a new integer encoding algorithm. Chris Angelico <rosuav@gmail.com> - 2015-02-18 20:36 +1100
        Re: python implementation of a new integer encoding algorithm. janhein.vanderburg@gmail.com - 2015-02-18 11:29 -0800
      Re: python implementation of a new integer encoding algorithm. Laura Creighton <lac@openend.se> - 2015-02-18 11:32 +0100
        Re: python implementation of a new integer encoding algorithm. janhein.vanderburg@gmail.com - 2015-02-18 11:48 -0800
      People hated it for the same reasons I found them cool (was: python implementation of a new integer encoding algorithm.) Ben Finney <ben+python@benfinney.id.au> - 2015-02-18 21:57 +1100
  Re: python implementation of a new integer encoding algorithm. Dave Angel <davea@davea.name> - 2015-02-17 09:12 -0500
    Re: python implementation of a new integer encoding algorithm. janhein.vanderburg@gmail.com - 2015-02-18 00:59 -0800
      Re: python implementation of a new integer encoding algorithm. Dave Angel <davea@davea.name> - 2015-02-18 11:46 -0500
        Re: python implementation of a new integer encoding algorithm. Grant Edwards <invalid@invalid.invalid> - 2015-02-18 17:30 +0000
          Re: python implementation of a new integer encoding algorithm. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-02-18 18:12 +0000
        Re: python implementation of a new integer encoding algorithm. janhein.vanderburg@gmail.com - 2015-02-18 11:55 -0800
          Re: python implementation of a new integer encoding algorithm. Marko Rauhamaa <marko@pacujo.net> - 2015-02-18 23:54 +0200
            Re: python implementation of a new integer encoding algorithm. Marko Rauhamaa <marko@pacujo.net> - 2015-02-19 00:08 +0200
            Re: python implementation of a new integer encoding algorithm. Grant Edwards <invalid@invalid.invalid> - 2015-02-18 22:58 +0000
          Re: python implementation of a new integer encoding algorithm. Dave Angel <davea@davea.name> - 2015-02-18 17:19 -0500
            Re: python implementation of a new integer encoding algorithm. janhein.vanderburg@gmail.com - 2015-02-19 07:45 -0800
              Re: python implementation of a new integer encoding algorithm. Ian Kelly <ian.g.kelly@gmail.com> - 2015-02-19 11:04 -0700
              Re: python implementation of a new integer encoding algorithm. Ian Kelly <ian.g.kelly@gmail.com> - 2015-02-19 11:16 -0700
              Re: python implementation of a new integer encoding algorithm. Dave Angel <davea@davea.name> - 2015-02-19 13:24 -0500
              Re: python implementation of a new integer encoding algorithm. Chris Angelico <rosuav@gmail.com> - 2015-02-20 05:34 +1100
              Re: python implementation of a new integer encoding algorithm. Ian Kelly <ian.g.kelly@gmail.com> - 2015-02-19 11:32 -0700
              Re: python implementation of a new integer encoding algorithm. Dave Angel <davea@davea.name> - 2015-02-19 13:41 -0500
              Re: python implementation of a new integer encoding algorithm. Dave Angel <davea@davea.name> - 2015-02-19 13:46 -0500
              Re: python implementation of a new integer encoding algorithm. Chris Angelico <rosuav@gmail.com> - 2015-02-20 05:49 +1100
      Re: python implementation of a new integer encoding algorithm. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-02-18 17:00 +0000
  Re: python implementation of a new integer encoding algorithm. Chris Angelico <rosuav@gmail.com> - 2015-02-18 01:34 +1100
    Re: python implementation of a new integer encoding algorithm. janhein.vanderburg@gmail.com - 2015-02-18 01:04 -0800
      Re: python implementation of a new integer encoding algorithm. Dave Angel <davea@davea.name> - 2015-02-18 08:54 -0500
        Re: python implementation of a new integer encoding algorithm. janhein.vanderburg@gmail.com - 2015-02-18 11:52 -0800
      Re: python implementation of a new integer encoding algorithm. Chris Angelico <rosuav@gmail.com> - 2015-02-19 01:16 +1100
  Re: python implementation of a new integer encoding algorithm. Dave Angel <davea@davea.name> - 2015-02-17 09:50 -0500
  Re: python implementation of a new integer encoding algorithm. Chris Angelico <rosuav@gmail.com> - 2015-02-18 01:58 +1100
  Re: python implementation of a new integer encoding algorithm. Dave Angel <davea@davea.name> - 2015-02-17 10:18 -0500
  Re: python implementation of a new integer encoding algorithm. Chris Angelico <rosuav@gmail.com> - 2015-02-18 02:25 +1100
  Re: python implementation of a new integer encoding algorithm. Paul Rubin <no.email@nospam.invalid> - 2015-02-17 08:43 -0800
    Re: python implementation of a new integer encoding algorithm. janhein.vanderburg@gmail.com - 2015-02-18 01:06 -0800
  Re: python implementation of a new integer encoding algorithm. Mario Figueiredo <marfig@gmail.com> - 2015-02-19 08:44 +0100
    Re: python implementation of a new integer encoding algorithm. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-02-19 08:06 +0000
      Re: python implementation of a new integer encoding algorithm. Marko Rauhamaa <marko@pacujo.net> - 2015-02-19 10:36 +0200
        Re: python implementation of a new integer encoding algorithm. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-02-19 09:33 +0000
        Re: python implementation of a new integer encoding algorithm. Terry Reedy <tjreedy@udel.edu> - 2015-02-19 14:50 -0500
          Re: python implementation of a new integer encoding algorithm. Marko Rauhamaa <marko@pacujo.net> - 2015-02-19 21:55 +0200
    Re: python implementation of a new integer encoding algorithm. Chris Angelico <rosuav@gmail.com> - 2015-02-19 19:36 +1100
    Re: python implementation of a new integer encoding algorithm. Mario Figueiredo <marfig@gmail.com> - 2015-02-19 10:42 +0100
    Re: python implementation of a new integer encoding algorithm. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-02-19 10:28 +0000
    Re: python implementation of a new integer encoding algorithm. Mario Figueiredo <marfig@gmail.com> - 2015-02-19 14:27 +0100
  Re: python implementation of a new integer encoding algorithm. Jonas Wielicki <jonas@wielicki.name> - 2015-02-19 09:38 +0100
    Re: python implementation of a new integer encoding algorithm. janhein.vanderburg@gmail.com - 2015-02-19 07:58 -0800
  Re: python implementation of a new integer encoding algorithm. Denis McMahon <denismfmcmahon@gmail.com> - 2015-02-20 02:46 +0000
    Re: python implementation of a new integer encoding algorithm. wxjmfauth@gmail.com - 2015-02-20 00:58 -0800

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