Re: Request for source code review of simple Ising model

From	glen herrmannsfeldt <gah@ugcs.caltech.edu>
Newsgroups	comp.lang.c
Subject	Re: Request for source code review of simple Ising model
Date	2014-04-17 09:32 +0000
Organization	Aioe.org NNTP Server
Message-ID	<lio73c$umb$1@speranza.aioe.org> (permalink)
References	(4 earlier) <0.65e770be25e0037ff45a.20140416013306BST.87ioqayuyl.fsf@bsb.me.uk> <878ur54fy1.fsf@panda.goosenet.in> <534E9A83.70101@verizon.net> <lnr44x6ywl.fsf@nuthaus.mib.org> <87vbu8a2n8.fsf@panda.goosenet.in>

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Udyant Wig <udyantw@gmail.com> wrote:

(snip, someone wrote)
> | If you don't mind making your code a bit non-portable (and in fact
> | systems where 0.0 and NULL *aren't* represented as all-bits-zero are
> | rare), then calloc() or memset() can be reasonable.  It will at least
> | make the initial contents of the allocated memory consistent, even if
> | it's not necessarily correct.

> As I did not use floats or doubles, I suppose the program is safe.

Is there a processor built in the last 50 years that doesn't use
all bits zero for floating point zero?

Using a biased exponent, an exponent of zero bits is the smallest
exponent, which a zero should have. 

From Blaauw and Brooks "Computer Architecture: Concepts and Evolution"

there are processors with sign magnitude, ones complement, or
twos complement exponents, Some such machines are the IBM 1620,
Ferranti Atlas, CDC 6600, Burroughs B5500, and the CDC STAR-100.

Even so, they could special case zero, which I believe some of
those do. I believe you will only find them running in a museum.

-- glen

Thread

Request for source code review of simple Ising model Udyant Wig <udyant@panda.goosenet.in> - 2014-04-10 23:38 +0530
  Re: Request for source code review of simple Ising model Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-10 13:30 -0700
    Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-12 00:34 +0530
      Re: Request for source code review of simple Ising model Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-11 12:25 -0700
      Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-16 01:12 +0530
        Re: Request for source code review of simple Ising model Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-04-16 01:33 +0100
          Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-16 17:57 +0530
            Re: Request for source code review of simple Ising model Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-16 06:00 -0700
            Re: Request for source code review of simple Ising model James Kuyper <jameskuyper@verizon.net> - 2014-04-16 10:58 -0400
              Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-16 09:07 -0700
                Re: Request for source code review of simple Ising model James Kuyper <jameskuyper@verizon.net> - 2014-04-16 12:22 -0400
                Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-16 10:38 -0700
                Re: Request for source code review of simple Ising model Kaz Kylheku <kaz@kylheku.com> - 2014-04-16 19:37 +0000
                Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-17 12:00 +0530
                Re: Request for source code review of simple Ising model glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-04-17 09:32 +0000
                Re: Request for source code review of simple Ising model "BartC" <bc@freeuk.com> - 2014-04-17 12:24 +0100
                Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-17 08:16 -0700
                Re: Request for source code review of simple Ising model Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-17 04:41 -0700
                Re: Request for source code review of simple Ising model Les Cargill <lcargill99@comcast.com> - 2014-04-17 07:49 -0500
                Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-17 08:00 -0700
                Re: Request for source code review of simple Ising model Kaz Kylheku <kaz@kylheku.com> - 2014-04-17 15:06 +0000
                Re: Request for source code review of simple Ising model Tim Rentsch <txr@alumni.caltech.edu> - 2014-04-18 21:04 -0700
                Re: Request for source code review of simple Ising model glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-04-17 18:38 +0000
                Re: Request for source code review of simple Ising model James Kuyper <jameskuyper@verizon.net> - 2014-04-17 15:26 -0400
                Re: Request for source code review of simple Ising model "BartC" <bc@freeuk.com> - 2014-04-17 21:00 +0100
                Re: Request for source code review of simple Ising model James Kuyper <jameskuyper@verizon.net> - 2014-04-17 16:34 -0400
                Re: Request for source code review of simple Ising model glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-04-18 04:31 +0000
                Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-17 14:05 -0700
                Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-17 17:06 -0700
                Re: Request for source code review of simple Ising model glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-04-18 04:54 +0000
                Re: Request for source code review of simple Ising model Tim Rentsch <txr@alumni.caltech.edu> - 2014-04-18 11:51 -0700
              Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-17 11:42 +0530
            Re: Request for source code review of simple Ising model Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-04-16 16:54 +0100
              Re: Request for source code review of simple Ising model Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-16 15:22 -0700
              Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-17 13:03 +0530
                Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-17 08:44 -0700
                Re: Request for source code review of simple Ising model James Kuyper <jameskuyper@verizon.net> - 2014-04-17 12:12 -0400
                Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-18 12:38 +0530
                Re: Request for source code review of simple Ising model Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-18 03:11 -0700
                Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-18 12:32 +0530
                Re: Request for source code review of simple Ising model James Kuyper <jameskuyper@verizon.net> - 2014-04-18 10:05 -0400
        Re: Request for source code review of simple Ising model Ike Naar <ike@iceland.freeshell.org> - 2014-04-16 07:10 +0000
        Re: Request for source code review of simple Ising model James Kuyper <jameskuyper@verizon.net> - 2014-04-17 13:10 -0400
          Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-18 18:24 +0530
            Re: Request for source code review of simple Ising model James Kuyper <jameskuyper@verizon.net> - 2014-04-18 09:52 -0400
              Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-18 20:04 +0530
                Re: Request for source code review of simple Ising model James Kuyper <jameskuyper@verizon.net> - 2014-04-18 11:00 -0400
                Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-20 01:49 +0530
                Re: Request for source code review of simple Ising model glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-04-19 21:20 +0000
                Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-20 11:11 +0530
                Re: Request for source code review of simple Ising model Richard Damon <Richard@Damon-Family.org> - 2014-04-20 09:06 -0400
                Re: Request for source code review of simple Ising model James Kuyper <jameskuyper@verizon.net> - 2014-04-20 10:50 -0400
                Re: Request for source code review of simple Ising model Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-21 09:14 -0700
              Re: Request for source code review of simple Ising model Ike Naar <ike@iceland.freeshell.org> - 2014-04-19 05:43 +0000
            Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-18 19:47 +0530
            Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-21 01:21 +0530
              Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-20 14:24 -0700
                Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-21 10:40 +0530
              Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-21 12:29 +0530
          Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-18 08:36 -0700
            Re: Request for source code review of simple Ising model James Kuyper <jameskuyper@verizon.net> - 2014-04-18 13:40 -0400
              Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-18 11:14 -0700
              Re: Request for source code review of simple Ising model Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-18 13:55 -0700
            Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-19 01:25 +0530
              Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-19 01:44 +0530
              Re: Request for source code review of simple Ising model Kaz Kylheku <kaz@kylheku.com> - 2014-04-18 20:24 +0000
              Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-18 13:36 -0700
                Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-19 20:18 +0530
              Re: Request for source code review of simple Ising model Richard <rgrdev_@gmail.com> - 2014-04-19 14:55 +0100
                Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-20 02:10 +0530
            Re: Request for source code review of simple Ising model Ike Naar <ike@iceland.freeshell.org> - 2014-04-19 05:40 +0000
              Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-19 14:39 -0700
                Re: Request for source code review of simple Ising model Ian Collins <ian-news@hotmail.com> - 2014-04-20 10:44 +1200
                Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-19 17:11 -0700
                Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-20 11:24 +0530
                Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-19 17:19 -0700
                Re: Request for source code review of simple Ising model Ike Naar <ike@iceland.freeshell.org> - 2014-04-20 10:10 +0000
                Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-20 14:21 -0700
                Re: Request for source code review of simple Ising model Ike Naar <ike@iceland.freeshell.org> - 2014-04-20 22:18 +0000
                Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-20 19:27 -0700
                Re: Request for source code review of simple Ising model Ike Naar <ike@iceland.freeshell.org> - 2014-04-21 12:38 +0000
                Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-21 18:12 +0530
                Re: Request for source code review of simple Ising model Ike Naar <ike@iceland.freeshell.org> - 2014-04-21 13:13 +0000
                Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-21 19:46 +0530
                Re: Request for source code review of simple Ising model Keith Thompson <kst-u@mib.org> - 2014-04-21 09:06 -0700
                Re: Request for source code review of simple Ising model jacob navia <jacob@spamsink.net> - 2014-04-21 00:26 +0200
        Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-18 01:15 +0530
        Re: Request for source code review of simple Ising model Udyant Wig <udyantw@gmail.com> - 2014-04-20 11:46 +0530

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