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

Groups > comp.lang.java.programmer > #38350

Re: Can Java compute 9^(9^9) ?

Show all headers | View raw

Maybe should try to switch to use this gem:

"This code has been merged into OpenJDK 8 except 
for the Schönhage-Strassen and Barrett algorithms 
which are planned for OpenJDK 9."
https://github.com/tbuktu/bigint

Oki Doki

Am Mittwoch, 6. Juni 2018 11:02:04 UTC+2 schrieb burs...@gmail.com:
> Corr.:
> I did another test right now, with pow/3, it 
> 
> Am Mittwoch, 6. Juni 2018 10:58:44 UTC+2 schrieb burs...@gmail.com:
> > No, no, they are not that smart, _ is not some functional
> > programming lazy, it only instructs the top-level to not
> > show the result. I can 100% assure you that. 
> > 
> > Storing the result in on the other hand in a file takes 
> > like 2 minutes. For the 8.5 secs blinding fast calculation,
> > I get file size 369'693'102 bigpow999.txt, so the calculation 
> > 
> > is possibly corrrect.
> > 
> > See also here, the Edit 06.06.2018:
> > https://math.stackexchange.com/a/2809007/4414
> > 
> > Its more the problem that Java probably doesn't implement
> > FFT multiplication, and the problem is above the threshold
> > where FFT would make sense. Or its some other problem 
> > with GC, dunno yet.
> > 
> > I didn't another test right now, with pow/3, it
> > shows that Java gets increasingly slower, whereby
> > GNU keeps the runtime for multiplication down:
> > 
> > Java, the (A*A)*B step measured:
> > 
> > % Up 1,059 ms, GC 14 ms, Thread Cpu 1,031 ms (Current 06/06/18 10:07:54)
> > % Up 2,320 ms, GC 11 ms, Thread Cpu 2,297 ms (Current 06/06/18 10:07:56)
> > % Up 5,852 ms, GC 27 ms, Thread Cpu 5,812 ms (Current 06/06/18 10:08:02)
> > % Up 15,949 ms, GC 179 ms, Thread Cpu 15,782 ms (Current 06/06/18 10:08:18)
> > % Up 45,419 ms, GC 540 ms, Thread Cpu 44,796 ms (Current 06/06/18 10:09:03)
> > % Up 116,740 ms, GC 1,234 ms, Thread Cpu 115,235 ms (Current 06/06/18 10:11:00)
> > % Up 326,318 ms, GC 2,266 ms, Thread Cpu 323,765 ms (Current 06/06/18 10:16:26)
> > 
> > GNU, the (A*A)*B step measured.
> > 
> > % 2 inferences, 0.047 CPU in 0.047 seconds (100% CPU, 43 Lips)
> > % 2 inferences, 0.094 CPU in 0.109 seconds (86% CPU, 21 Lips)
> > % 2 inferences, 0.203 CPU in 0.219 seconds (93% CPU, 10 Lips)
> > % 2 inferences, 0.438 CPU in 0.484 seconds (90% CPU, 5 Lips)
> > % 2 inferences, 0.875 CPU in 0.984 seconds (89% CPU, 2 Lips)
> > % 2 inferences, 1.828 CPU in 2.062 seconds (89% CPU, 1 Lips)
> > % 2 inferences, 3.859 CPU in 4.202 seconds (92% CPU, 1 Lips)
> > 
> > Am Mittwoch, 6. Juni 2018 10:51:05 UTC+2 schrieb Andreas Leitgeb:
> > > bursejan@gmail.com <bursejan@gmail.com> wrote:
> > > > The 8.5 secs are plausible. I already tested another
> > > > system, which could do it in around 20 secs.
> > > >
> > > >   ECLiPSe Constraint Logic Programming System [kernel threads]
> > > >   Version 7.0 #36 (x86_64_nt), Sun Jan 28 10:18 2018
> > > >
> > > >   [eclipse 2]: _ is 9^(9^9).
> > > >   Yes (20.09s cpu)
> > > >
> > > > So the magnitude of this time measure is plausible.
> > > > I did not double check the result, the 370 mio digits. 
> > > >
> > > > Not sure whether I should check the result..
> > > 
> > > Maybe, both SWI-Prolog and ECLiPSe are both smart in detecting
> > > and avoiding calculations "assigned" to "_".
> > > 
> > > Unless you can store the result in a variable and query some
> > > properties of it for checking it might just have skipped some
> > > of the calculations.

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

Thread

Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-01 10:20 -0700
  Re: Can Java compute 9^(9^9) ? Eric Sosman <esosman@comcast-dot-net.invalid> - 2018-06-01 13:36 -0400
    Re: Can Java compute 9^(9^9) ? j4n bur53 <janburse@fastmail.fm> - 2018-06-01 20:20 +0200
      Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-05 07:17 -0700
        Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-05 07:29 -0700
          Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-05 07:48 -0700
          Re: Can Java compute 9^(9^9) ? Eric Sosman <esosman@comcast-dot-net.invalid> - 2018-06-05 10:57 -0400
            Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-05 09:32 -0700
              Re: Can Java compute 9^(9^9) ? Eric Sosman <esosman@comcast-dot-net.invalid> - 2018-06-05 13:58 -0400
                Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-05 11:10 -0700
                Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-05 11:21 -0700
                Re: Can Java compute 9^(9^9) ? Andreas Leitgeb <avl@logic.at> - 2018-06-06 08:50 +0000
                Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-06 01:58 -0700
                Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-06 02:01 -0700
                Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-06 10:34 -0700
  Re: Can Java compute 9^(9^9) ? j4n bur53 <janburse@fastmail.fm> - 2018-06-09 21:06 +0200
    Re: Can Java compute 9^(9^9) ? v_borchert@despammed.com (Volker Borchert) - 2018-06-09 23:29 +0000
      Re: Can Java compute 9^(9^9) ? Martin Gregorie <martin@mydomain.invalid> - 2018-06-10 09:13 +0000
        Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-10 02:31 -0700
          Re: Can Java compute 9^(9^9) ? Arne Vajhøj <arne@vajhoej.dk> - 2018-06-10 18:28 -0400
            Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-10 15:48 -0700
              Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-10 15:52 -0700
                Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-10 15:58 -0700
              Re: Can Java compute 9^(9^9) ? Arne Vajhøj <arne@vajhoej.dk> - 2018-06-10 21:17 -0400
                Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-11 13:20 -0700
                Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-14 13:37 -0700

csiph-web