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Groups > comp.lang.c > #138557
| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Big integers |
| Date | 2018-12-05 13:46 -0800 |
| Organization | None to speak of |
| Message-ID | <lnftvblk9o.fsf@kst-u.example.com> (permalink) |
| References | <YfuND.286973$lKb.275890@fx15.am4> <01c809d8-12f2-4755-8207-a000f1d6c9c1@googlegroups.com> <%VyND.512769$p%6.229167@fx26.am4> <pu7031$1d82$1@gioia.aioe.org> |
jacob navia <jacob@jacob.remcomp.fr> writes:
> Le 04/12/2018 à 18:35, Bart a écrit :
> > 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?)
> I have written one, based on the work of Stephen L Moshier, in x86 asm
> and arm64 asm. It has aroud the same speed as GMP...
> The layout is as follows:
>
> Each number is 64 bytes, where the first 32 are the sign (I know is
> wasteful but it is faster than using only one bit) the, the next 32 are
> the exponent (biased) and then 7 64 bit integers with the mantissa.
>
> All functions of the C standard library are provided using this format
So you have a sign, a 32-bit exponent, and a 448-bit mantissa.
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).
To represent 1/3 *exactly*, you need either trinary (which
can't represent 1/5 or 1/7 exactly, or even 1/2) or some kind of
numerator/denominator representation.
--
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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