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Re: Big integers

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From Keith Thompson <kst-u@mib.org>
Newsgroups comp.lang.c
Subject Re: Big integers
Date Wed, 05 Dec 2018 22:40:09 -0800
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jacobnavia <jacob@jacob.remcomp.fr> writes:
> Le 05/12/2018 à 22:46, Keith Thompson a écrit :
>> So you have a sign, a 32-bit exponent, and a 448-bit mantissa.
>
> yes
>
>> Unless I'm missing something, that still can't represent 1/3 exactly
>> (though it can approximate it much more closely than smaller formats
>> can).
>
> For ANY base <n> there will be always some number that is not exactly
> representable in that base. For instance in base 10, 1/3 is
>
> 0.333333333...
>
> Apparently for you this is a "bug" in my software or what?

No, not at all.  I was simply responding to your remarks upthread.

Bart wrote:
    An extended precision floating point library would also be
    intriguing to write. But it can't be arbitrary precision. (How many
    digits to represent 1/3 exactly in either binary or decimal?)

You replied:
    I have written one, based on the work of Stephen L Moshier, in x86
    asm and arm64 asm.

I took that as a claim that your system could represent 1/3 exactly.
Re-reading it, I see that you were probably responding to the
"extended precision" part of what Bart wrote, not to the "can't be
arbitrary precision" part.  As usual, I intended no personal attack.
(I understand that you don't believe that, but there's nothing I
can do about that.)

[snip]

-- 
Keith Thompson (The_Other_Keith) kst@mib.org  <http://www.ghoti.net/~kst>
Will write code for food.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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Big integers Bart <bc@freeuk.com> - 2018-12-04 12:17 +0000
  Re: Big integers fir <profesor.fir@gmail.com> - 2018-12-04 05:58 -0800
    Re: Big integers Chad <cdalten@gmail.com> - 2018-12-04 08:22 -0800
      Re: Big integers Bart <bc@freeuk.com> - 2018-12-04 17:04 +0000
        Re: Big integers scott@slp53.sl.home (Scott Lurndal) - 2018-12-04 17:19 +0000
  Re: Big integers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-12-04 08:38 -0800
    Re: Big integers Bart <bc@freeuk.com> - 2018-12-04 17:35 +0000
      Re: Big integers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-12-04 18:13 +0000
        Re: Big integers "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-12-04 10:50 -0800
        Re: Big integers Rosario19 <Ros@invalid.invalid> - 2018-12-06 17:56 +0100
      Re: Big integers Thiago Adams <thiago.adams@gmail.com> - 2018-12-04 10:22 -0800
        Re: Big integers Eli the Bearded <*@eli.users.panix.com> - 2018-12-04 18:58 +0000
          Re: Big integers Thiago Adams <thiago.adams@gmail.com> - 2018-12-04 11:32 -0800
            Re: Big integers Eli the Bearded <*@eli.users.panix.com> - 2018-12-04 22:45 +0000
              Re: Big integers jameskuyper@alumni.caltech.edu - 2018-12-04 14:57 -0800
          Re: Big integers jameskuyper@alumni.caltech.edu - 2018-12-04 12:14 -0800
          Re: Big integers chris.m.thomasson.1@gmail.com - 2018-12-04 16:58 -0800
            Re: Big integers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-12-05 03:14 +0000
              Re: Big integers "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-05 14:27 -0800
            Re: Big integers Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2018-12-04 20:03 -0500
              Re: Big integers "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-05 14:25 -0800
      Re: Big integers jacob navia <jacob@jacob.remcomp.fr> - 2018-12-04 23:45 +0100
        Re: Big integers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-12-04 23:29 +0000
        Re: Big integers Bart <bc@freeuk.com> - 2018-12-05 00:30 +0000
          Re: Big integers "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-05 14:28 -0800
        Re: Big integers Jens Stuckelberger <Jens_Stuckelberger@nowhere.net> - 2018-12-05 17:50 +0000
          Re: Big integers jacobnavia <jacob@jacob.remcomp.fr> - 2018-12-05 20:03 +0100
        Re: Big integers Keith Thompson <kst-u@mib.org> - 2018-12-05 13:46 -0800
          Re: Big integers jacobnavia <jacob@jacob.remcomp.fr> - 2018-12-06 06:41 +0100
            Re: Big integers Keith Thompson <kst-u@mib.org> - 2018-12-05 22:40 -0800
  Re: Big integers "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-12-04 09:08 -0800
    Re: Big integers Bart <bc@freeuk.com> - 2018-12-04 19:41 +0000
      Re: Big integers "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-12-04 12:00 -0800
    Re: Big integers Bart <bc@freeuk.com> - 2018-12-08 11:28 +0000
  Re: Big integers Ian Collins <ian-news@hotmail.com> - 2018-12-05 15:19 +1300
    Re: Big integers Bart <bc@freeuk.com> - 2018-12-05 11:58 +0000
      Re: Big integers David Brown <david.brown@hesbynett.no> - 2018-12-05 14:35 +0100
        Re: Big integers Bart <bc@freeuk.com> - 2018-12-05 14:35 +0000
          Re: Big integers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-12-05 07:39 -0800
            Re: Big integers Thiago Adams <thiago.adams@gmail.com> - 2018-12-05 07:45 -0800
              Re: Big integers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-12-05 17:51 +0000
                Re: Big integers David Brown <david.brown@hesbynett.no> - 2018-12-05 22:19 +0100
              Re: Big integers "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-05 14:55 -0800
                Re: Big integers jameskuyper@alumni.caltech.edu - 2018-12-05 15:19 -0800
                Re: Big integers "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-05 16:13 -0800
                Re: Big integers David Brown <david.brown@hesbynett.no> - 2018-12-06 09:35 +0100
                Re: Big integers "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-07 14:26 -0800
                Re: Big integers "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-07 19:56 -0800
                Re: Big integers James Kuyper <jameskuyper@alumni.caltech.edu> - 2018-12-09 12:01 -0500
                Re: Big integers "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-10 14:47 -0800
                Re: Big integers scott@slp53.sl.home (Scott Lurndal) - 2018-12-11 00:50 +0000
                Re: Big integers "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-10 17:37 -0800
                Re: Big integers "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-14 21:18 -0800
          Re: Big integers Thiago Adams <thiago.adams@gmail.com> - 2018-12-05 07:57 -0800
          Re: Big integers Bart <bc@freeuk.com> - 2018-12-05 15:59 +0000
            Re: Big integers Bart <bc@freeuk.com> - 2018-12-05 22:59 +0000
              Re: Big integers jameskuyper@alumni.caltech.edu - 2018-12-05 15:31 -0800
                Re: Big integers Robert Wessel <robertwessel2@yahoo.com> - 2018-12-05 20:03 -0600
              Re: Big integers scott@slp53.sl.home (Scott Lurndal) - 2018-12-05 23:42 +0000
                Re: Big integers James Kuyper <jameskuyper@alumni.caltech.edu> - 2018-12-05 20:15 -0500
              Re: Big integers Ike Naar <ike@iceland.freeshell.org> - 2018-12-10 07:26 +0000
                Re: Big integers Bart <bc@freeuk.com> - 2018-12-10 18:38 +0000
                Re: Big integers scott@slp53.sl.home (Scott Lurndal) - 2018-12-10 19:10 +0000
                Re: Big integers Bart <bc@freeuk.com> - 2018-12-10 21:23 +0000
                Re: Big integers Ike Naar <ike@iceland.freeshell.org> - 2018-12-10 22:47 +0000
          Re: Big integers David Brown <david.brown@hesbynett.no> - 2018-12-05 22:15 +0100
        Re: Big integers Bart <bc@freeuk.com> - 2018-12-06 13:43 +0000
          Re: Big integers Thiago Adams <thiago.adams@gmail.com> - 2018-12-06 07:50 -0800
      Re: Big integers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-12-05 15:19 +0000
        Re: Big integers luser droog <luser.droog@gmail.com> - 2018-12-10 23:19 -0800
          Re: Big integers David Brown <david.brown@hesbynett.no> - 2018-12-11 08:45 +0100
            Re: Big integers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-12-11 11:15 +0000
              Re: Big integers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-12-11 04:36 -0800
                Re: Big integers David Brown <david.brown@hesbynett.no> - 2018-12-11 14:35 +0100
              Re: Modules again (was: Big integers) Bart <bc@freeuk.com> - 2018-12-11 12:53 +0000
                Re: Modules again David Brown <david.brown@hesbynett.no> - 2018-12-11 14:45 +0100
                Re: Modules again Bart <bc@freeuk.com> - 2018-12-11 16:08 +0000
                Re: Modules again David Brown <david.brown@hesbynett.no> - 2018-12-11 21:37 +0100
                Re: Modules again Thiago Adams <thiago.adams@gmail.com> - 2018-12-11 08:59 -0800
                Re: Modules again Bart <bc@freeuk.com> - 2018-12-11 17:49 +0000
                Re: Modules again David Brown <david.brown@hesbynett.no> - 2018-12-11 21:44 +0100
                Re: Modules again scott@slp53.sl.home (Scott Lurndal) - 2018-12-11 18:02 +0000
                Re: Modules again Thiago Adams <thiago.adams@gmail.com> - 2018-12-11 10:10 -0800
                Re: Modules again scott@slp53.sl.home (Scott Lurndal) - 2018-12-11 18:54 +0000
                Re: Modules again Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2018-12-11 13:14 -0500
                Re: Modules again scott@slp53.sl.home (Scott Lurndal) - 2018-12-11 18:54 +0000
                Re: Modules again Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2018-12-11 14:42 -0500
                Re: Modules again David Brown <david.brown@hesbynett.no> - 2018-12-11 21:54 +0100
                Re: Modules again Keith Thompson <kst-u@mib.org> - 2018-12-11 14:53 -0800
                Re: Modules again David Brown <david.brown@hesbynett.no> - 2018-12-12 08:24 +0100
                Re: Modules again David Brown <david.brown@hesbynett.no> - 2018-12-11 21:51 +0100
                Re: Modules again scott@slp53.sl.home (Scott Lurndal) - 2018-12-11 23:24 +0000
                Re: Modules again Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2018-12-11 18:44 -0500
                Re: Modules again Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2018-12-11 18:45 -0500
                Re: Modules again Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-12-12 06:39 +0000
                Re: Modules again James Kuyper <jameskuyper@alumni.caltech.edu> - 2018-12-12 07:59 -0500
                Re: Modules again mark.bluemel@gmail.com - 2018-12-12 05:43 -0800
                Re: Modules again scott@slp53.sl.home (Scott Lurndal) - 2018-12-12 14:20 +0000
                Re: Modules again David Brown <david.brown@hesbynett.no> - 2018-12-12 17:10 +0100
                Re: Modules again James Kuyper <jameskuyper@alumni.caltech.edu> - 2018-12-12 13:39 -0800
                Re: Modules again scott@slp53.sl.home (Scott Lurndal) - 2018-12-12 14:19 +0000
                Re: Modules again Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2018-12-12 10:28 -0500
      Re: Big integers Ian Collins <ian-news@hotmail.com> - 2018-12-06 08:10 +1300
        Re: Big integers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-12-05 20:57 +0000
          Re: Big integers Ian Collins <ian-news@hotmail.com> - 2018-12-06 10:16 +1300
            Re: Big integers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-12-05 23:15 +0000
              Re: Big integers scott@slp53.sl.home (Scott Lurndal) - 2018-12-05 23:44 +0000
  Re: Big integers Robert Wessel <robertwessel2@yahoo.com> - 2018-12-05 02:51 -0600
  Re: Big integers antispam@math.uni.wroc.pl - 2018-12-07 15:26 +0000
    Re: Big integers Bart <bc@freeuk.com> - 2018-12-07 16:27 +0000
      Re: Big integers scott@slp53.sl.home (Scott Lurndal) - 2018-12-07 16:36 +0000
        Re: Big integers Bart <bc@freeuk.com> - 2018-12-07 17:01 +0000
      Re: Big integers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-12-07 17:55 +0000
      Re: Big integers antispam@math.uni.wroc.pl - 2018-12-07 19:26 +0000
        Re: Big integers Bart <bc@freeuk.com> - 2018-12-07 21:39 +0000
          Re: Big integers Ian Collins <ian-news@hotmail.com> - 2018-12-08 10:51 +1300
  Re: Big integers Anton Shepelev <anton.txt@gmail.com> - 2018-12-08 00:43 +0300
    Re: Big integers Bart <bc@freeuk.com> - 2018-12-08 01:08 +0000
    Re: Big integers David Brown <david.brown@hesbynett.no> - 2018-12-08 15:13 +0100
      Re: Big integers David Brown <david.brown@hesbynett.no> - 2018-12-08 15:15 +0100
        Re: Big integers Bart <bc@freeuk.com> - 2018-12-08 14:48 +0000
          Re: Big integers Thiago Adams <thiago.adams@gmail.com> - 2018-12-10 05:10 -0800
            Re: Big integers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-12-10 05:22 -0800
              Re: Big integers David Brown <david.brown@hesbynett.no> - 2018-12-10 15:27 +0100
                Re: Big integers scott@slp53.sl.home (Scott Lurndal) - 2018-12-10 15:59 +0000
                Re: Big integers antispam@math.uni.wroc.pl - 2018-12-11 21:14 +0000
            Re: Big integers Bart <bc@freeuk.com> - 2018-12-10 14:56 +0000
              Re: Big integers Ike Naar <ike@iceland.freeshell.org> - 2018-12-10 17:46 +0000
                Re: Big integers Bart <bc@freeuk.com> - 2018-12-10 18:24 +0000
                Re: Big integers Thiago Adams <thiago.adams@gmail.com> - 2018-12-10 11:12 -0800
                Re: Big integers Thiago Adams <thiago.adams@gmail.com> - 2018-12-10 11:23 -0800
                Re: Big integers Bart <bc@freeuk.com> - 2018-12-10 21:44 +0000
                Re: Big integers Thiago Adams <thiago.adams@gmail.com> - 2018-12-11 10:20 -0800
                Re: Big integers "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-11 13:15 -0800
      Re: Big integers Keith Thompson <kst-u@mib.org> - 2018-12-08 12:14 -0800
        Re: Big integers David Brown <david.brown@hesbynett.no> - 2018-12-09 13:31 +0100
      Re: Big integers "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-08 15:52 -0800
  Re: Big integers Bart <bc@freeuk.com> - 2018-12-16 19:29 +0000
  Re: Big integers "Tristan B. Kildaire" <deavmi@disroot.org> - 2018-12-25 12:59 +0000
    Re: Big integers Bart <bc@freeuk.com> - 2018-12-25 15:54 +0000

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