Re: Strawmans prime sieve/filter

From	Dr J R Stockton <reply1300@merlyn.demon.co.uk.invalid>
Newsgroups	comp.lang.javascript
Subject	Re: Strawmans prime sieve/filter
Date	2013-09-12 20:17 +0100
Organization	Home
Message-ID	<KIdkZJh1MhMSFwD1@invalid.uk.co.demon.merlyn.invalid> (permalink)
References	<6e464d33-47e4-41b8-bfda-19511de92915@googlegroups.com> <l0jgv8$g2u$1@news.albasani.net> <a13c125d-e801-43e3-9e12-4355b40e22d2@googlegroups.com> <l0kcd7$ol$1@news.albasani.net> <3251928.WeJvBNZfad@PointedEars.de>

Show all headers | View raw

In comp.lang.javascript message <3251928.WeJvBNZfad@PointedEars.de>,
Wed, 11 Sep 2013 10:39:33, Thomas 'PointedEars' Lahn
<PointedEars@web.de> posted:

>Stefan Weiss wrote:
>
>> […] I just calculated the [prime] numbers up to 200M. There are 11078937
>> of them, which would require ~44MB of storage (using 4 bytes to store a
>> number). If I went the full 2B, the necessary disk storage would still be
>> less than half a gig. […]
>
>The relevant ECMAScript implementations support only one numeric data type,
>Number, which is an implementation of IEEE-754 double-precision floating-
>point values.  Each such value requires 64 bits of storage (1 sign bit, 11
>exponent bits, and 52 mantissa bits), or _8_ bytes whereas each byte
>consists of 8 bits.

But perhaps it has not occurred to you that, /in extremis/, one can
store nearly 64 bits in an ECMAScript IEEE-754 Double.  IIRC, of the
2^64 bit patterns in an 8 byte Double, two represent the infinities, and
about 2^53 represent NaN, which ECMAScript cannot "resolve".

One can very easily store 32 bits in a Number, using the integer values
0 to 2^32-1.

-- 
 (c) John Stockton, Surrey, UK.  ¬@merlyn.demon.co.uk   Turnpike v6.05   MIME.
   Web  <http://www.merlyn.demon.co.uk/> - FAQish topics, acronyms, & links.
 Proper <= 4-line sig. separator as above, a line exactly "-- " (SonOfRFC1036)
 Do not Mail News to me. Before a reply, quote with ">" or "> " (SonOfRFC1036)

Thread

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

csiph-web