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Re: Sum of squares

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In article <5785867.675.1333044979048.JavaMail.geo-discussion-forums@ynjc20>,
Helmar Wodtke  <helmwo@gmail.com> wrote:
>Am Donnerstag, 29. M=C3=A4rz 2012 19:33:58 UTC+2 schrieb Alexander Adler:
>> albert@spenarnc.xs4all.nl schrieb:
<SNIP>  <Other problem skipped>
>> >
>> > A much more interesting problem is:
>> >    It is well-known that a prime is the sum of 2 squares in exactly
>> >    one way 1]. Find them.
<SNIP>    < One of two algorithms skipped>
>> > Groetjes Albert
>> >
>> > --
>>=20
>> Cheers,                                                 Alexander.
>
>The joke about this is:
>
>1010150873 =3D 16187^2 + 27352^2
>
>real   0m0.035s
>user   0m0.036s
>sys    0m0.000s
>
>(yours)
>
>1010150873 --- s1 =3D 16187 s2 =3D 27352 result: 1010150873=20
>
>real   0m0.024s
>user   0m0.020s
>sys    0m0.004s
>
>(mine)
>
>(this was done by forth4p)
>
>Now for Gforth, as it is shiped by Ubuntu LTS:
>
>1010150873 =3D 16187^2 + 27352^2
>
>real   0m0.015s
>user   0m0.016s
>sys    0m0.000s
>
>(yours)
>
>1010150873 --- s1 =3D 16187 s2 =3D 27352 result: 1010150873=20
>
>real   0m0.018s
>user   0m0.012s
>sys    0m0.008s
>
>(mine)
>
>The differences (at least at input that fits what my implementation can do)=
> is not really big. You use sophisticated math, I use a basically simple id=
>ea.
>I'm not sure you can speed up processing if you would have 2000 processor c=
>ores more - I can do (by factor, 2000 because this problem is like this).

Let's have a look what happens if the numbers get a tad bigger.
"
calculate .results
1000000000000000177 --- s1 = 633708561 s2  = 773571884
result: 1000000000000000177
 ok

real    1m50.927s
user    1m50.860s
sys     0m0.020s
 "
That's right: your solutions takes 2 minutes on the same machine and
Forth that took 500 uS before.
It demonstrates dramatically what difference an algorithm makes.
Even your 2000 machines together would take .1 second.

>
>But nice - I did not think that much how to get it better.
>
>Regards,
>-Helmar


--
-- 
Albert van der Horst, UTRECHT,THE NETHERLANDS
Economic growth -- being exponential -- ultimately falters.
albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst

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Sum of squares mhx@iae.nl (Marcel Hendrix) - 2012-03-26 20:50 +0200
  Re: Sum of squares "A. K." <akk@nospam.org> - 2012-03-26 21:43 +0200
  Re: Sum of squares Paul Rubin <no.email@nospam.invalid> - 2012-03-26 16:52 -0700
    Re: Sum of squares Helmar Wodtke <helmwo@gmail.com> - 2012-03-27 03:15 -0700
      Re: Sum of squares Paul Rubin <no.email@nospam.invalid> - 2012-03-28 08:16 -0700
    Re: Sum of squares BruceMcF <agila61@netscape.net> - 2012-03-28 06:06 -0700
  Re: Sum of squares Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2012-03-27 12:13 +0100
    Re: Sum of squares Helmar Wodtke <helmwo@gmail.com> - 2012-03-27 04:03 -0700
      Re: Sum of squares Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2012-03-27 13:55 +0100
  Re: Sum of squares Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-27 11:05 +0000
    Re: Sum of squares Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-28 11:41 +0000
      Re: Sum of squares Paul Rubin <no.email@nospam.invalid> - 2012-03-28 07:41 -0700
      Re: Sum of squares mhx@iae.nl (Marcel Hendrix) - 2012-03-29 22:06 +0200
      Re: Sum of squares Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-31 11:48 +0000
    Re: Sum of squares Alexander Adler <alexander.adler@stud.uni-frankfurt.de> - 2012-03-29 19:33 +0200
      Re: Sum of squares Helmar Wodtke <helmwo@gmail.com> - 2012-03-29 11:16 -0700
        Re: Sum of squares Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-04-03 09:47 +0000
    Re: Sum of squares Helmar Wodtke <helmwo@gmail.com> - 2012-03-28 09:42 -0700
    Re: Sum of squares Helmar Wodtke <helmwo@gmail.com> - 2012-03-28 11:08 -0700
  Re: Sum of squares Ecki <ecki@intershop.de> - 2012-03-27 16:15 +0200
    Re: Sum of squares Helmar Wodtke <helmwo@gmail.com> - 2012-03-27 07:35 -0700
      Re: Sum of squares hwfwguy@gmail.com - 2012-03-27 08:00 -0700
        Re: Sum of squares Helmar Wodtke <helmwo@gmail.com> - 2012-03-27 08:21 -0700
        Re: Sum of squares Ecki <ecki@intershop.de> - 2012-03-29 09:05 +0200

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