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Groups > comp.lang.javascript > #21252
| From | "Chris M. Thomasson" <no@spam.invalid> |
|---|---|
| Newsgroups | comp.lang.javascript |
| Subject | Re: Strawmans prime sieve/filter |
| Date | 2013-09-10 08:52 -0700 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <l0nf7q$6sp$1@speranza.aioe.org> (permalink) |
| References | <6e464d33-47e4-41b8-bfda-19511de92915@googlegroups.com> <l0jgv8$g2u$1@news.albasani.net> <5837258c-4fbe-4c8d-a432-b7e8e5b59495@googlegroups.com> <l0m5vq$j4m$1@speranza.aioe.org> |
"Chris M. Thomasson" wrote in message
news:l0m5vq$j4m$1@speranza.aioe.org...
[...]
> FWIW, here is stupid simple code that finds 1,270,607 prime numbers out of
> 20,000,000 with average time of 12,500 milliseconds on my little notebook
> using Firefox:
> ______________________________________________________________
> [...]
> function count_prime(m)
> {
> var c = 0;
>
> for (var n = 2; n < m; ++n)
> if (is_prime(n)) ++c;
>
> return c;
> }
> [...]
> ______________________________________________________________
This tiny "optimization" of the function above shaves off a couple seconds
of runtime:
______________________________________________________________
function count_prime(m)
{
var c = 0;
for (var n = 2; n < m; ++n)
{
if (is_prime(n)) ++c;
if (n > 2) ++n;
}
return c;
}
______________________________________________________________
Might as well skip all of the even numbers greater than two...
;^)
Since no even numbers other than two will ever be passed to the `is_prime()'
function, you can remove one of mod operations. Actually, I don't know why
I used the mod in the first place when, in this case, bitwise AND will do
the
trick!
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Strawmans prime sieve/filter jonas.thornvall@gmail.com - 2013-09-08 19:09 -0700
Re: Strawmans prime sieve/filter Stefan Weiss <krewecherl@gmail.com> - 2013-09-09 05:57 +0200
Re: Strawmans prime sieve/filter jonas.thornvall@gmail.com - 2013-09-08 21:22 -0700
Re: Strawmans prime sieve/filter jonas.thornvall@gmail.com - 2013-09-08 21:50 -0700
Re: Strawmans prime sieve/filter Stefan Weiss <krewecherl@gmail.com> - 2013-09-09 13:45 +0200
Re: Strawmans prime sieve/filter jonas.thornvall@gmail.com - 2013-09-09 06:33 -0700
Re: Strawmans prime sieve/filter jonas.thornvall@gmail.com - 2013-09-09 06:41 -0700
Re: Strawmans prime sieve/filter Stefan Weiss <krewecherl@gmail.com> - 2013-09-09 18:37 +0200
Re: Strawmans prime sieve/filter Stefan Weiss <krewecherl@gmail.com> - 2013-09-09 19:54 +0200
Re: Strawmans prime sieve/filter jonas.thornvall@gmail.com - 2013-09-09 12:46 -0700
Re: Strawmans prime sieve/filter Stefan Weiss <krewecherl@gmail.com> - 2013-09-09 23:25 +0200
Re: Strawmans prime sieve/filter jonas.thornvall@gmail.com - 2013-09-09 14:58 -0700
Re: Strawmans prime sieve/filter Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-09-11 10:39 +0200
Re: Strawmans prime sieve/filter jonas.thornvall@gmail.com - 2013-09-11 02:54 -0700
Re: Strawmans prime sieve/filter Stefan Weiss <krewecherl@gmail.com> - 2013-09-11 12:59 +0200
Re: Strawmans prime sieve/filter Dr J R Stockton <reply1300@merlyn.demon.co.uk.invalid> - 2013-09-12 20:17 +0100
Re: Strawmans prime sieve/filter Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-09-13 02:27 +0200
Re: Strawmans prime sieve/filter Stefan Weiss <krewecherl@gmail.com> - 2013-09-13 04:03 +0200
Re: Strawmans prime sieve/filter jonas.thornvall@gmail.com - 2013-09-12 19:30 -0700
Re: Strawmans prime sieve/filter Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-09-13 05:15 +0200
Re: Strawmans prime sieve/filter Stefan Weiss <krewecherl@gmail.com> - 2013-09-13 05:27 +0200
Re: Strawmans prime sieve/filter jonas.thornvall@gmail.com - 2013-09-13 08:26 -0700
Re: Strawmans prime sieve/filter jonas.thornvall@gmail.com - 2013-09-13 08:15 -0700
Re: Strawmans prime sieve/filter Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-09-13 19:13 +0200
Re: Strawmans prime sieve/filter jonas.thornvall@gmail.com - 2013-09-13 17:15 -0700
Re: Strawmans prime sieve/filter Ben Bacarisse <ben.usenet@bsb.me.uk> - 2013-09-14 01:55 +0100
Re: Strawmans prime sieve/filter Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-09-14 04:20 +0200
Re: Strawmans prime sieve/filter Ben Bacarisse <ben.usenet@bsb.me.uk> - 2013-09-14 06:16 +0100
Re: Strawmans prime sieve/filter Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-09-14 12:10 +0200
Re: Strawmans prime sieve/filter Ben Bacarisse <ben.usenet@bsb.me.uk> - 2013-09-14 12:49 +0100
Re: Strawmans prime sieve/filter Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-09-14 15:23 +0200
Re: Strawmans prime sieve/filter Ben Bacarisse <ben.usenet@bsb.me.uk> - 2013-09-14 21:51 +0100
Re: Strawmans prime sieve/filter Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-09-15 03:32 +0200
Re: Strawmans prime sieve/filter Ben Bacarisse <ben.usenet@bsb.me.uk> - 2013-09-15 04:07 +0100
Re: Strawmans prime sieve/filter Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-09-15 18:57 +0200
Re: Strawmans prime sieve/filter Ben Bacarisse <ben.usenet@bsb.me.uk> - 2013-09-15 19:24 +0100
Re: Strawmans prime sieve/filter jonas.thornvall@gmail.com - 2013-09-14 20:37 -0700
Re: Strawmans prime sieve/filter Dr J R Stockton <reply1300@merlyn.demon.co.uk.invalid> - 2013-09-14 19:38 +0100
Re: Strawmans prime sieve/filter jonas.thornvall@gmail.com - 2013-09-08 22:26 -0700
Re: Strawmans prime sieve/filter Ben Bacarisse <ben.usenet@bsb.me.uk> - 2013-09-10 22:48 +0100
Re: Strawmans prime sieve/filter jonas.thornvall@gmail.com - 2013-09-11 00:36 -0700
Re: Strawmans prime sieve/filter Ben Bacarisse <ben.usenet@bsb.me.uk> - 2013-09-11 14:47 +0100
Re: Strawmans prime sieve/filter jonas.thornvall@gmail.com - 2013-09-08 22:33 -0700
Re: Strawmans prime sieve/filter "Chris M. Thomasson" <no@spam.invalid> - 2013-09-09 21:08 -0700
Re: Strawmans prime sieve/filter "Chris M. Thomasson" <no@spam.invalid> - 2013-09-10 08:52 -0700
Re: Strawmans prime sieve/filter Dr J R Stockton <reply1300@merlyn.demon.co.uk.invalid> - 2013-09-10 19:08 +0100
Re: Strawmans prime sieve/filter "Chris M. Thomasson" <no@spam.invalid> - 2014-04-10 22:02 -0700
Re: Strawmans prime sieve/filter "Chris M. Thomasson" <no@spam.invalid> - 2014-05-02 15:39 -0700
Re: Strawmans prime sieve/filter "Chris M. Thomasson" <no@spam.invalid> - 2014-05-02 15:54 -0700
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