Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > comp.lang.java.programmer > #15204

Re: Quick n-th Square of BigInteger

From Jan Burse <janburse@fastmail.fm>
Newsgroups comp.lang.java.programmer
Subject Re: Quick n-th Square of BigInteger
Date 2012-06-11 14:53 +0200
Organization albasani.net
Message-ID <jr4po0$sbs$1@news.albasani.net> (permalink)
References <jqtian$er7$1@news.albasani.net> <jqtpd1$jda$1@dont-email.me>

Show all headers | View raw


Eric Sosman schrieb:
>      BigInteger lo = BigInteger.ONE.shiftLeft(
>          Math.floor((x.bitCount()-1)/n));
>      BitInteger hi = BigInteger.ONE.shiftLeft(
>          Math.ceil(x.bitCount()/n));

I guess you mean bitLength() and not bitCount()
in the above. bitCount() counts the number of
non-zero bits. bitLength() gives the index of
the highest non-zero bit.

Math.floor/Math.ceil are not really needed in the
above since (int)/(int) gives anyway (int). But
I am now going for. Also correcting BitInteger
to BigInteger:

       BigInteger lo = BigInteger.ONE.shiftLeft(
           (x.bitLength()-1)/n);
       BigInteger hi = BigInteger.ONE.shiftLeft(
           (x.bitLength()+n-1)/n);

I am not yet done with testing. Bisection works
already, but would like to compare with Newton.
Here is an example run showing determination of
lo and hi:

   x=1000000000
   n=3
   lo=512
   hi=1024

Bye

Back to comp.lang.java.programmer | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

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

csiph-web