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Re: StringBuilder Difficulties

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From blmblm@myrealbox.com <blmblm.myrealbox@gmail.com>
Newsgroups comp.lang.java.programmer
Subject Re: StringBuilder Difficulties
Date 4 Jul 2011 03:32:50 GMT
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In article <CZGdnS-Ag6OPR5LTnZ2dnUVZ_oqdnZ2d@earthlink.com>,
Patricia Shanahan  <pats@acm.org> wrote:
> On 7/2/2011 6:34 PM, blmblm@myrealbox.com wrote:
> ...
> > Both programs (yours and mine) now consistently report sequential
> > search to be faster than binary search.  Weird, but not as weird as
> > the two being different in that regard ....
> ...
> 
> Binary search can have a much higher constant multiplier on its time
> than sequential search. If the searches are long enough, the O(log n) vs
> O(n) complexity difference should dominate over the constant multiplier,
> but for short searches the constant multiplier can dominate.

Of course -- I know better than to think computational complexity
is the whole story, especially in dealing with small problem sizes,
which I think is what we have here.  (Why I notice this kind of 
"what was I thinking?" only after posting, who knows.)

> Binary search is more expensive than it looks because of branch
> prediction.

Which makes sense ....  

[ snip ]

> The only way to know which way round this will come out is indeed to
> measure, making sure the searches are as similar as possible to the real
> workload.

Which is apparently by no means straightforward in Java!  I recently
skimmed through the articles by Brian Goetz referenced in one of
Stefan Ram's posts from a while back, and -- fascinating stuff.

-- 
B. L. Massingill
ObDisclaimer:  I don't speak for my employers; they return the favor.

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StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-06-28 17:54 -0700
  Re: StringBuilder Difficulties Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-06-28 21:29 -0400
    Re: StringBuilder Difficulties Lew <noone@lewscanon.com> - 2011-06-29 00:48 -0400
      Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-06-29 12:19 -0700
    Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-06-29 12:11 -0700
      Re: StringBuilder Difficulties Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-06-29 22:06 -0400
  Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-06-29 20:17 +0000
    Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-06-29 18:55 -0700
      Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-06-30 20:30 +0000
        Re: StringBuilder Difficulties Patricia Shanahan <pats@acm.org> - 2011-06-30 14:17 -0700
          Re: StringBuilder Difficulties Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-06-30 21:36 -0400
            Re: StringBuilder Difficulties "John B. Matthews" <nospam@nospam.invalid> - 2011-07-01 01:41 -0400
        Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-06-30 14:26 -0700
          Re: StringBuilder Difficulties Steve Sobol <sjsobol@JustThe.net> - 2011-06-30 17:33 -0700
          Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-07-01 20:47 +0000
            Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-07-01 17:29 -0700
              Re: StringBuilder Difficulties rossum <rossum48@coldmail.com> - 2011-07-02 11:36 +0100
              Re: StringBuilder Difficulties Robert Klemme <shortcutter@googlemail.com> - 2011-07-02 12:58 +0200
                Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-07-04 07:52 -0700
                Re: StringBuilder Difficulties Robert Klemme <shortcutter@googlemail.com> - 2011-07-04 21:45 +0200
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-05 02:06 -0400
                Re: StringBuilder Difficulties markspace <-@.> - 2011-07-05 09:32 -0700
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-05 14:13 -0400
                Re: StringBuilder Difficulties markspace <-@.> - 2011-07-05 12:51 -0700
                Re: StringBuilder Difficulties Silvio <silvio@moc.com> - 2011-07-05 23:16 +0200
                Re: StringBuilder Difficulties markspace <-@.> - 2011-07-05 15:08 -0700
                Re: StringBuilder Difficulties Silvio <silvio@moc.com> - 2011-07-06 09:41 +0200
                Re: StringBuilder Difficulties "eye" <eye@mocka.com> - 2011-07-06 09:55 +0000
                Re: StringBuilder Difficulties thoolen <thoolen@tholenbot.thorium> - 2011-07-06 05:37 -0400
                Re: StringBuilder Difficulties "thoolen" <thoolen@tholenbot.thorium> - 2011-07-06 08:43 -0400
                Re: StringBuilder Difficulties thoolen <thoolen@tholenbot.thorium> - 2011-07-06 22:30 -0400
                Re: StringBuilder Difficulties "Stefan Robacki" <noemail@noemail.foobar> - 2011-07-06 00:04 -0400
                Re: StringBuilder Difficulties thoolen <thoolen@tholenbot.thorium> - 2011-07-06 05:45 -0400
                Re: StringBuilder Difficulties thoolen <thoolen@tholenbot.thorium> - 2011-07-06 08:26 -0400
                Re: StringBuilder Difficulties thoolen <thoolen@tholenbot.thorium> - 2011-07-06 22:36 -0400
                Re: StringBuilder Difficulties "tholen@antispam.ham" <tholen@ifa.hawaii.edu> - 2011-07-06 06:09 -0700
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-06 22:40 -0400
                Re: StringBuilder Difficulties John Doe <jdoe@usenetlove.invalid> - 2011-07-14 06:50 +0000
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-14 02:58 -0400
                Re: StringBuilder Difficulties Jane Doe <jdoe@love.in.d.jungle.invalid> - 2011-07-14 10:20 -0400
                Re: StringBuilder Difficulties thoolen <tholen01@gmail.com> - 2011-07-14 07:33 -0700
                Re: StringBuilder Difficulties Stanimir Stamenkov <s7an10@netscape.net> - 2011-07-05 23:44 +0300
                Re: StringBuilder Difficulties markspace <-@.> - 2011-07-05 14:08 -0700
              Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-07-02 18:33 +0000
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-02 16:56 -0400
                Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-07-03 01:34 +0000
                Re: StringBuilder Difficulties Patricia Shanahan <pats@acm.org> - 2011-07-02 19:55 -0700
                Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-07-04 03:32 +0000
                Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-07-04 08:04 -0700
                Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-07-05 19:12 +0000
                Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-07-05 14:06 -0700
                Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-07-05 21:16 +0000
                Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-07-05 17:29 -0700
                Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-07-06 16:59 +0000
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-06 19:52 -0400
                Re: StringBuilder Difficulties Patricia Shanahan <pats@acm.org> - 2011-07-06 16:58 -0700
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-06 19:52 -0400
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-06 21:54 -0400
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-06 22:18 -0400
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-06 22:41 -0400
                Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-07-08 17:45 +0000
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-06 05:48 -0400
                Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-07-06 16:59 +0000
                Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-07-06 10:56 -0700
                Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-07-08 17:44 +0000
                Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-07-08 11:51 -0700
                Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-07-10 19:08 +0000
                Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-07-11 07:54 -0700
                Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-07-11 22:37 +0000
                Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-07-11 15:52 -0700
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-06 08:25 -0400
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-06 19:41 -0400
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-06 19:58 -0400
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-06 21:57 -0400
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-06 22:17 -0400
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-06 22:44 -0400
                Re: StringBuilder Difficulties Steve Erwin <trollHunter@Usenet.4.usenetizens.org.invalid> - 2011-07-07 12:51 +1000
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-06 23:02 -0400
                Re: StringBuilder Difficulties John Doe <jdoe@usenetlove.invalid> - 2011-07-14 06:32 +0000
                Re: StringBuilder Difficulties supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-07-14 02:57 -0400
                Re: StringBuilder Difficulties Jane Doe <jdoe@love.in.d.jungle.invalid> - 2011-07-14 10:07 -0400
                Re: StringBuilder Difficulties thoolen <tholen01@gmail.com> - 2011-07-14 07:24 -0700
                Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-07-04 07:58 -0700
                Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-07-05 19:09 +0000
                Re: StringBuilder Difficulties KitKat <kitkat_11697@gmail.example.com> - 2011-07-05 15:15 -0400
                Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-07-05 20:03 +0000
                Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-07-05 14:11 -0700
                Re: StringBuilder Difficulties blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-07-06 16:55 +0000
      Re: StringBuilder Difficulties lewbloch <lewbloch@gmail.com> - 2011-07-03 00:08 -0700
        Re: StringBuilder Difficulties Robert Klemme <shortcutter@googlemail.com> - 2011-07-03 12:35 +0200
          Re: StringBuilder Difficulties lewbloch <lewbloch@gmail.com> - 2011-07-04 04:07 -0700
  Re: StringBuilder Difficulties Patricia Shanahan <pats@acm.org> - 2011-06-29 14:38 -0700
    Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-06-29 15:00 -0700
      Re: StringBuilder Difficulties Patricia Shanahan <pats@acm.org> - 2011-06-29 15:52 -0700
        Re: StringBuilder Difficulties Gene Wirchenko <genew@ocis.net> - 2011-06-29 18:58 -0700
          Re: StringBuilder Difficulties Patricia Shanahan <pats@acm.org> - 2011-06-29 19:26 -0700
          Re: StringBuilder Difficulties lewbloch <lewbloch@gmail.com> - 2011-07-03 00:11 -0700
  Re: StringBuilder Difficulties Roedy Green <see_website@mindprod.com.invalid> - 2011-06-29 18:32 -0700

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