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Groups > comp.lang.c > #138606
| Subject | Re: Big integers |
|---|---|
| Newsgroups | comp.lang.c |
| References | <YfuND.286973$lKb.275890@fx15.am4> <pue3fg$ihs$1@z-news.wcss.wroc.pl> <8cxOD.372639$Nt6.46513@fx19.am4> <puehgl$qjh$1@z-news.wcss.wroc.pl> |
| From | Bart <bc@freeuk.com> |
| Message-ID | <vMBOD.927889$8Q.288956@fx36.am4> (permalink) |
| Organization | virginmedia.com |
| Date | 2018-12-07 21:39 +0000 |
On 07/12/2018 19:26, antispam@math.uni.wroc.pl wrote: > Bart <bc@freeuk.com> wrote: > There are _huge_ speed differences between various bignum libraries. Apparently. >> (My library produced a result using 3**10**6 (not 3**10**7) in about 30 >> seconds for the multiply (uing gcc-O3). The result had 954,243 digits. >> How many had your result?) > > 31699251 bits, that is 9542426 digits. The first six are 124277... Well, my library seems to be on the right lines at least. My code uses decimal representation, which has some penalty (involving divide and mod ops in the inner loop of the already naive multiply). But changing it to binary, while keeping the same algorithm, will probably have little impact. Since decimal has some advantages, I will keep it like that for the time being, and perhaps get back to the algorithms at some later point. At the minute I've started a floating point version, also decimal. >> Somebody may want to multiply numbers 2-3 magnitudes bigger than yours, >> then even gmp might take too long. > > Actually, memory is more problematic: for interesting computations > one needs several numbers and with 4Mb each you can have reasonably > many numbers even on small machine like the one I am using now. > 3 magnitudes bigger means 4Gb per number No, I meant each number might be 100 or 1000 times bigger (so any 10 extra bits). But I now see this won't much much difference, not for multiply. So I really mean calculations big enough you have to wait a while for the results. But apparently you work with those too. > Well, our needs are different. I have computations that can take > days or weeks using GMP. Slower library could change this to > months or years. Compared to this difference in compile time > is negilgible. The biggest factorial on my Casio is 69!, and it only gives a result to 10 figures (which takes half a second) Even my toy library can instantly give the exact answer. As it can for 10000! So for this undemanding stuff it's adequate.
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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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