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Groups > comp.lang.java.programmer > #15138
| From | glen herrmannsfeldt <gah@ugcs.caltech.edu> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: Quick n-th Square of BigInteger |
| Date | 2012-06-08 23:34 +0000 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <jqu25k$6f4$1@speranza.aioe.org> (permalink) |
| References | <jqtian$er7$1@news.albasani.net> <dlu4t7llbfgb1n8esgs5hbjhn7t2hb6ft8@4ax.com> <jqtuqh$9uo$1@news.albasani.net> |
Jan Burse <janburse@fastmail.fm> wrote: (snip) > x^(2*n+1) = (x^n)^2*x > From the Java source code of Oracle JDK 1.7: > // Perform exponentiation using repeated squaring trick > They even do it in a loop. Yes. > But question is about floor(root(x,n)), which > might profit from a fast pow() of course. The suggestion is to do binary search, computing x**n until you find the appropriate n. It depends much on the size of x and n, though. I suppose you can save some multiplies by saving the largest previously found x**n that is less than y. Well, start the loop by squaring until you get a value larger than y, then you have two powers that you know n is between, saving the lower value each time. Now binary search over that range, each time saving the highest known power such that the result doesn't exceed y. -- glen
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Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-08 21:03 +0200
Re: Quick n-th Square of BigInteger Gene Wirchenko <genew@ocis.net> - 2012-06-08 13:34 -0700
Quick n-th Root of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-08 22:36 +0200
Re: Quick n-th Root of BigInteger markspace <-@.> - 2012-06-08 13:55 -0700
Re: Quick n-th Root of BigInteger glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-06-08 21:06 +0000
Re: Quick n-th Root of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-08 23:21 +0200
Re: Quick n-th Root of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-08 23:34 +0200
Re: Quick n-th Root of BigInteger Lew <lewbloch@gmail.com> - 2012-06-08 14:43 -0700
Re: Quick n-th Root of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-08 23:47 +0200
Re: Quick n-th Root of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-08 23:47 +0200
Re: Quick n-th Root of BigInteger Lew <lewbloch@gmail.com> - 2012-06-08 14:55 -0700
Re: Quick n-th Root of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 00:00 +0200
Re: Quick n-th Root of BigInteger Lew <lewbloch@gmail.com> - 2012-06-08 15:10 -0700
Re: Quick n-th Root of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 00:12 +0200
Re: Quick n-th Root of BigInteger Lew <lewbloch@gmail.com> - 2012-06-08 15:18 -0700
Re: Quick n-th Root of BigInteger glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-06-08 22:59 +0000
Re: Quick n-th Root of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 01:05 +0200
Re: Quick n-th Root of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 01:00 +0200
Re: Quick n-th Root of BigInteger Lew <lewbloch@gmail.com> - 2012-06-08 16:15 -0700
Re: Quick n-th Root of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 01:51 +0200
Re: Quick n-th Root of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 02:32 +0200
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-08 23:00 +0200
Re: Quick n-th Square of BigInteger Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-08 17:04 -0400
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-08 23:19 +0200
Re: Quick n-th Square of BigInteger Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-08 17:40 -0400
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-08 23:43 +0200
Re: Quick n-th Square of BigInteger Lew <lewbloch@gmail.com> - 2012-06-08 14:52 -0700
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 00:30 +0200
Re: Quick n-th Square of BigInteger glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-06-08 23:05 +0000
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-11 14:53 +0200
Re: Quick n-th Square of BigInteger Roedy Green <see_website@mindprod.com.invalid> - 2012-06-08 15:32 -0700
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 00:37 +0200
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 00:39 +0200
Re: Quick n-th Square of BigInteger glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-06-08 23:34 +0000
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 01:44 +0200
Re: Quick n-th Square of BigInteger glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-06-09 01:06 +0000
Re: Quick n-th Square of BigInteger glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-06-08 23:25 +0000
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 01:29 +0200
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 01:29 +0200
Re: Quick n-th Square of BigInteger Wanja Gayk <brixomatic@yahoo.com> - 2012-06-17 15:00 +0200
Re: Quick n-th Square of BigInteger Leif Roar Moldskred <leifm@dimnakorr.com> - 2012-06-09 08:42 -0500
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 16:54 +0200
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 17:56 +0200
Re: Quick n-th Square of BigInteger Leif Roar Moldskred <leifm@dimnakorr.com> - 2012-06-09 12:52 -0500
Re: Quick n-th Square of BigInteger Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-06-09 12:55 -0400
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 21:23 +0200
Re: Quick n-th Square of BigInteger Leif Roar Moldskred <leifm@dimnakorr.com> - 2012-06-09 12:44 -0500
Re: Quick n-th Square of BigInteger markspace <-@.> - 2012-06-09 11:50 -0700
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 21:13 +0200
Re: Quick n-th Square of BigInteger markspace <-@.> - 2012-06-09 12:25 -0700
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-09 21:29 +0200
Re: Quick n-th Square of BigInteger Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-06-09 21:27 -0400
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-10 12:08 +0200
Re: Quick n-th Square of BigInteger Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-06-10 08:23 -0400
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-10 13:31 +0200
Re: Quick n-th Square of BigInteger Wanja Gayk <brixomatic@yahoo.com> - 2012-06-17 15:11 +0200
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-10 12:04 +0200
Re: Quick n-th Square of BigInteger Roedy Green <see_website@mindprod.com.invalid> - 2012-06-16 17:45 -0700
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-17 03:17 +0200
Re: Quick n-th Square of BigInteger Jan Burse <janburse@fastmail.fm> - 2012-06-17 03:38 +0200
Troll Parade Closing, Award Ceremony Jan Burse <janburse@fastmail.fm> - 2012-06-10 12:31 +0200
Re: Troll Parade Closing, Award Ceremony Jan Burse <janburse@fastmail.fm> - 2012-06-10 12:35 +0200
Re: Troll Parade Closing, Award Ceremony Leif Roar Moldskred <leifm@dimnakorr.com> - 2012-06-10 06:28 -0500
Re: Troll Parade Closing, Award Ceremony Jan Burse <janburse@fastmail.fm> - 2012-06-10 13:30 +0200
Re: Troll Parade Closing, Award Ceremony Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-06-10 08:25 -0400
Re: Troll Parade Closing, Award Ceremony Jan Burse <janburse@fastmail.fm> - 2012-06-10 14:48 +0200
Re: Troll Parade Closing, Award Ceremony Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-06-10 11:49 -0700
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