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| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Float Vs Double |
| Date | 2016-08-23 17:18 +0100 |
| Organization | A noiseless patient Spider |
| Message-ID | <87d1kzqx02.fsf@bsb.me.uk> (permalink) |
| References | (16 earlier) <nphepg$1dn$3@jstuckle.eternal-september.org> <nphhqp$db1$1@dont-email.me> <nphjp1$k66$1@jstuckle.eternal-september.org> <87shtvr2rg.fsf@bsb.me.uk> <nphn56$de$1@jstuckle.eternal-september.org> |
Jerry Stuckle <jstucklex@attglobal.net> writes: > On 8/23/2016 10:14 AM, Ben Bacarisse wrote: >> Jerry Stuckle <jstucklex@attglobal.net> writes: >> >>> On 8/23/2016 9:07 AM, David Brown wrote: >> <snip> >>>> And in either case, I can't see why storing 9 digits in 32-bit chunks is >>>> going to be much more complicated than storing 1 or 2 digits in 8-bit >>>> chunks (BCD, packed or unpacked). It will certainly be more efficient >>>> for calculations. 18 digits in 64-bit chunks is going to be even better >>>> on modern cpus. >> >> Maybe. The advantage of base 10^9 is that the result of any single >> digit multiplication fits in 64 bits. If you have a 64-bit to 128-bit >> multiply them, sure, use base 10^18, but if you don't, or you want to >> write the code in portable C, then 10^9 is probably better. > > The smart thing to do would be to store them as 32 (or 64) bit integers > and let the processor do the multiplication in its native format. What is the "them"? The numbers themselves don't fit into single 32 bit (or 64 bit) integers, and if you meed the base 10^9 (or base 10^18) digits, then what else do you think it being suggested here? >>> Then you show how to subtract 123.456 from 789012.345678 using 18 digits >>> in 64 bit chunks. I'd love to see you do it. >> >> It's the same as I showed for base 1,000,000,000 only base 10^18. The >> numbers are represented with two digits -- one before and one after the >> point. The position of the point is signalled with a count: >> >> (1, [789012, 345678000000000000]) - (1, [123, 456000000000000000]) >> >> Again, because 456000000000000000 > 345678000000000000 the subtraction >> involves a "borrow" to give: >> >> (1, [789012 - 123 - 1, 10^18 + 345678000000000000 - 456000000000000000]) > > Total fail. Let's see some actual code to do it. I'm not your performing monkey. If anyone *else* would like to see C code for this I'll take the time to do it, but experience shows that once this stage is reached no even code for obvious algorithms like the above will persuade you. <snip> -- Ben.
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Float Vs Double Real Troll <real.troll@trolls.com> - 2016-08-07 17:59 -0400
Re: Float Vs Double Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-07 23:38 +0100
Re: Float Vs Double Real Troll <real.troll@trolls.com> - 2016-08-07 18:55 -0400
Re: Float Vs Double jameskuyper@verizon.net - 2016-08-07 16:43 -0700
Re: Float Vs Double Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-07 19:36 -0700
Re: Float Vs Double Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-08 04:05 +0100
Re: Float Vs Double Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-07 20:41 -0700
Re: Float Vs Double Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-08 11:41 +0100
Re: Float Vs Double Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-08 04:23 -0700
Re: Float Vs Double Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-08 23:45 +0100
Re: Float Vs Double Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-10 03:26 -0700
Re: Float Vs Double Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-11 01:00 +0100
Re: Float Vs Double jameskuyper@verizon.net - 2016-08-08 08:52 -0700
Re: Float Vs Double James Kuyper <jameskuyper@verizon.net> - 2016-08-08 11:58 -0400
Re: Float Vs Double Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-08 10:06 -0700
Re: Float Vs Double "James R. Kuyper" <jameskuyper@verizon.net> - 2016-08-08 19:46 -0400
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-07 21:29 -0400
Re: Float Vs Double jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-08 14:04 +0200
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-08 09:00 -0400
Re: Float Vs Double jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-08 18:43 +0200
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-08 14:34 -0400
Re: Float Vs Double Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-08 12:00 -0700
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-08 16:42 -0400
Re: Float Vs Double Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-08 14:04 -0700
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-09 08:48 -0400
Re: Float Vs Double Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-10 03:22 -0700
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-21 18:31 -0400
Re: Float Vs Double supercat@casperkitty.com - 2016-08-22 08:39 -0700
Re: Float Vs Double Jean-Marc Bourguet <jm@bourguet.org> - 2016-08-22 19:29 +0200
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-22 19:24 -0400
Re: Float Vs Double Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-23 01:01 +0100
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-22 21:58 -0400
Re: Float Vs Double David Brown <david.brown@hesbynett.no> - 2016-08-23 09:38 +0200
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-23 08:15 -0400
Re: Float Vs Double David Brown <david.brown@hesbynett.no> - 2016-08-23 15:07 +0200
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-23 09:40 -0400
Re: Float Vs Double Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-23 15:14 +0100
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-23 10:38 -0400
Re: Float Vs Double Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-23 17:18 +0100
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-23 15:47 -0400
Re: Float Vs Double David Brown <david.brown@hesbynett.no> - 2016-08-23 16:39 +0200
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-23 11:45 -0400
Re: Float Vs Double David Brown <david.brown@hesbynett.no> - 2016-08-23 21:42 +0200
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-23 15:52 -0400
Re: Float Vs Double Ian Collins <ian-news@hotmail.com> - 2016-08-24 08:36 +1200
Re: Float Vs Double David Brown <david.brown@hesbynett.no> - 2016-08-24 09:39 +0200
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-24 11:31 -0400
Re: Float Vs Double Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-23 10:48 +0100
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-23 08:17 -0400
Re: Float Vs Double Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-23 06:01 -0700
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-23 09:44 -0400
Re: Float Vs Double Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-23 07:19 -0700
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-23 10:39 -0400
Re: Float Vs Double Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-23 08:18 -0700
Re: Float Vs Double Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-23 14:47 +0100
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-23 10:40 -0400
Re: Float Vs Double Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-24 01:31 +0100
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-23 20:53 -0400
Re: Float Vs Double supercat@casperkitty.com - 2016-08-23 23:20 -0700
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-24 11:32 -0400
Re: Float Vs Double David Brown <david.brown@hesbynett.no> - 2016-08-24 09:46 +0200
Re: Float Vs Double Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-24 14:53 +0100
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-24 11:35 -0400
Re: Float Vs Double Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-24 08:57 -0700
Re: Float Vs Double Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-24 17:36 +0100
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-24 12:50 -0400
Re: Float Vs Double Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-24 17:26 +0100
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-24 12:51 -0400
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-24 11:33 -0400
Re: Float Vs Double Robert Wessel <robertwessel2@yahoo.com> - 2016-08-28 02:33 -0500
Re: Float Vs Double antispam@math.uni.wroc.pl - 2016-08-31 22:36 +0000
Re: Float Vs Double supercat@casperkitty.com - 2016-08-31 15:51 -0700
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-08-31 22:42 -0400
Re: Float Vs Double supercat@casperkitty.com - 2016-09-01 08:32 -0700
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-01 15:00 -0400
Re: Float Vs Double supercat@casperkitty.com - 2016-09-01 13:45 -0700
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-01 20:50 -0400
Re: Float Vs Double supercat@casperkitty.com - 2016-09-02 08:11 -0700
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-02 12:25 -0400
Re: Float Vs Double David Brown <david.brown@hesbynett.no> - 2016-09-02 20:42 +0200
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-02 16:25 -0400
Re: Float Vs Double Jean-Marc Bourguet <jm@bourguet.org> - 2016-09-03 08:43 +0200
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-03 10:48 -0400
Re: Float Vs Double Jean-Marc Bourguet <jm@bourguet.org> - 2016-09-03 19:43 +0200
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-03 18:16 -0400
Re: Float Vs Double asetofsymbols@gmail.com - 2016-09-08 11:18 -0700
Re: Float Vs Double Robert Wessel <robertwessel2@yahoo.com> - 2016-09-07 19:59 -0500
Re: Float Vs Double supercat@casperkitty.com - 2016-09-08 08:13 -0700
Re: Float Vs Double Robert Wessel <robertwessel2@yahoo.com> - 2016-09-08 19:34 -0500
Re: Float Vs Double supercat@casperkitty.com - 2016-09-09 07:50 -0700
Re: Float Vs Double Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-02 23:40 -0700
Re: Float Vs Double Jean-Marc Bourguet <jm@bourguet.org> - 2016-09-03 09:06 +0200
Re: Float Vs Double Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-03 10:52 -0400
Re: Float Vs Double Rosario19 <Ros@invalid.invalid> - 2016-08-24 08:57 +0200
Re: Float Vs Double Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-24 01:04 -0700
Re: Float Vs Double Ike Naar <ike@iceland.freeshell.org> - 2016-08-08 06:44 +0000
Re: Float Vs Double Keith Thompson <kst-u@mib.org> - 2016-08-08 00:16 -0700
Re: Float Vs Double Richard Damon <Richard@Damon-Family.org> - 2016-08-08 23:29 -0400
Re: Float Vs Double jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-08 14:03 +0200
Re: Float Vs Double "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-08 05:14 -0700
Re: Float Vs Double BGB <cr88192@hotmail.com> - 2016-08-09 19:53 -0500
Re: Float Vs Double "James R. Kuyper" <jameskuyper@verizon.net> - 2016-08-07 18:47 -0400
Float Vs Double "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-07 17:04 -0700
Re: Float Vs Double "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-08 05:49 -0700
Re: Float Vs Double Nobody <nobody@nowhere.invalid> - 2016-08-10 03:26 +0100
Re: Float Vs Double "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-09 20:15 -0700
Re: Float Vs Double "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-10 06:07 -0700
Re: Float Vs Double "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-10 06:13 -0700
Re: Float Vs Double David Brown <david.brown@hesbynett.no> - 2016-08-10 16:43 +0200
Re: Float Vs Double "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-10 07:56 -0700
Re: Float Vs Double supercat@casperkitty.com - 2016-08-10 08:39 -0700
Re: Float Vs Double Keith Thompson <kst-u@mib.org> - 2016-08-10 09:56 -0700
Re: Float Vs Double Keith Thompson <kst-u@mib.org> - 2016-08-10 10:04 -0700
Re: Float Vs Double Tim Rentsch <txr@alumni.caltech.edu> - 2016-08-11 07:08 -0700
Re: Float Vs Double "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-11 07:15 -0700
Re: Float Vs Double Tim Rentsch <txr@alumni.caltech.edu> - 2016-08-12 08:11 -0700
Re: Float Vs Double jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-10 20:38 +0200
Re: Float Vs Double Keith Thompson <kst-u@mib.org> - 2016-08-10 12:20 -0700
Re: Float Vs Double supercat@casperkitty.com - 2016-08-10 12:17 -0700
Re: Float Vs Double jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-10 21:48 +0200
Re: Float Vs Double Keith Thompson <kst-u@mib.org> - 2016-08-10 13:40 -0700
Re: Float Vs Double Ian Collins <ian-news@hotmail.com> - 2016-08-12 08:01 +1200
Re: Float Vs Double BGB <cr88192@hotmail.com> - 2016-08-10 15:00 -0500
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