Re: complex number in struct form in C

From	Kaz Kylheku <kaz@kylheku.com>
Newsgroups	comp.lang.c
Subject	Re: complex number in struct form in C
Date	2014-12-27 17:23 +0000
Organization	Aioe.org NNTP Server
Message-ID	<20141227091411.674@kylheku.com> (permalink)
References	(5 earlier) <cfod3vFtubaU1@mid.individual.net> <f03e9ap9a4qac9er1qb2hi4dtb5nq00978@4ax.com> <62472149-c09e-42d6-9789-3d62b9b3cdf0@googlegroups.com> <YRjnw.322428$607.90723@fx21.am4> <e7414fe4-cc6d-42f6-968d-76170f8d3172@googlegroups.com>

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On 2014-12-27, asetofsymbols@gmail.com <asetofsymbols@gmail.com> wrote:
> If one has a fixed point number, if I understand right, one has too a way for
> check if result is correct... For float not fixed point one can not be
> sure... Than one can make errors with fixed point too...

Here is the thing. Both fixed and floating-point use rational numbers to
approximate real numbers. Except in certain cases, both representations
introduce error, due to their approximative nature. These errors can be
understood and quantified. That understanding and quantification is one of the
jobs of the numeric analyst.

A limitation shared by both fixed and floating-point numbers is that
although they represent rational numers, they in fact cannot represent
all rational numbers.

For example, a binary floating-point representation can perfectly
represent 1/2, 1/4, 1/8, ... but not 1/3, 1/5 or 1/10.
The same can be said of binary fixed-point representation.

A binary fixed point with three bits of fractional precision gives you
fractional parts which are combinations of 1/2, 1/4 and 1/8. That's it!
In other words, the fractions .000, .001, .010, .011, ..., .111.

So not only do these representations provide *only* an approximation of the
real numbers, they also only approximate many rational numbers, too.

This is okay; the approximations are good enough for real work: building
a bridge, landing a rover on Mars, and so on.

Thread

complex number in struct form in C Dexterr <dejangru@gmail.com> - 2014-12-21 07:20 -0800
  Re: complex number in struct form in C James Kuyper <jameskuyper@verizon.net> - 2014-12-21 11:30 -0500
    Re: complex number in struct form in C Dexterr <dejangru@gmail.com> - 2014-12-21 08:35 -0800
      Re: complex number in struct form in C "Osmium" <r124c4u102@comcast.net> - 2014-12-21 10:54 -0600
        Re: complex number in struct form in C James Kuyper <jameskuyper@verizon.net> - 2014-12-21 12:00 -0500
          Re: complex number in struct form in C "Osmium" <r124c4u102@comcast.net> - 2014-12-21 11:08 -0600
            Re: complex number in struct form in C Barry Schwarz <schwarzb@dqel.com> - 2014-12-21 10:12 -0800
              Re: complex number in struct form in C "Osmium" <r124c4u102@comcast.net> - 2014-12-21 13:22 -0600
                Re: complex number in struct form in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-12-21 22:21 +0000
              Re: complex number in struct form in C asetofsymbols@gmail.com - 2014-12-26 11:34 -0800
                Re: complex number in struct form in C "Osmium" <r124c4u102@comcast.net> - 2014-12-26 14:10 -0600
                Re: complex number in struct form in C glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-12-28 07:04 +0000
                Re: complex number in struct form in C BartC <bc@freeuk.com> - 2014-12-28 13:14 +0000
                Re: complex number in struct form in C Robert Wessel <robertwessel2@yahoo.com> - 2014-12-28 10:45 -0600
                Re: complex number in struct form in C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-28 08:56 -0800
                Re: complex number in struct form in C glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-12-29 10:10 +0000
                Re: complex number in struct form in C Kaz Kylheku <kaz@kylheku.com> - 2014-12-29 19:40 +0000
                Re: complex number in struct form in C glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-12-29 20:54 +0000
                Re: complex number in struct form in C BartC <bc@freeuk.com> - 2014-12-29 21:55 +0000
                Re: complex number in struct form in C glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-12-30 03:07 +0000
                Re: complex number in struct form in C BartC <bc@freeuk.com> - 2014-12-30 10:51 +0000
                Re: complex number in struct form in C Rosario193 <Rosario@invalid.invalid> - 2014-12-30 12:15 +0100
                Re: complex number in struct form in C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-30 03:31 -0800
                Re: complex number in struct form in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-12-30 12:17 +0000
                Re: complex number in struct form in C BartC <bc@freeuk.com> - 2014-12-30 13:18 +0000
                Re: complex number in struct form in C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-30 05:28 -0800
                Re: complex number in struct form in C BartC <bc@freeuk.com> - 2014-12-30 13:53 +0000
                Re: complex number in struct form in C "Osmium" <r124c4u102@comcast.net> - 2014-12-30 08:53 -0600
                Re: complex number in struct form in C "Chris M. Thomasson" <no@spam.invalid> - 2014-12-30 20:05 -0800
                Re: complex number in struct form in C Jeff Higgins <jeff@invalid.invalid> - 2014-12-30 17:40 -0500
                Re: complex number in struct form in C Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-24 08:58 -0700
                Re: complex number in struct form in C Les Cargill <lcargill99@comcast.com> - 2015-03-24 19:41 -0500
                Re: complex number in struct form in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-12-30 14:59 +0000
                Re: complex number in struct form in C David Thompson <dave.thompson2@verizon.net> - 2015-01-12 15:33 -0500
                Re: complex number in struct form in C glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-01-12 22:51 +0000
                Re: complex number in struct form in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-01-12 23:34 +0000
                Re: complex number in struct form in C James Kuyper <jameskuyper@verizon.net> - 2014-12-26 15:25 -0500
                Re: complex number in struct form in C glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-12-28 07:17 +0000
                Re: complex number in struct form in C BartC <bc@freeuk.com> - 2014-12-26 20:49 +0000
                Re: complex number in struct form in C asetofsymbols@gmail.com - 2014-12-27 00:22 -0800
                Re: complex number in struct form in C "Osmium" <r124c4u102@comcast.net> - 2014-12-27 08:25 -0600
                Re: complex number in struct form in C Geoff <geoff@invalid.invalid> - 2014-12-27 10:20 -0800
                Re: complex number in struct form in C "Osmium" <r124c4u102@comcast.net> - 2014-12-27 13:21 -0600
                Re: complex number in struct form in C Geoff <geoff@invalid.invalid> - 2014-12-27 13:11 -0800
                Re: complex number in struct form in C "Osmium" <r124c4u102@comcast.net> - 2014-12-27 15:36 -0600
                Re: complex number in struct form in C Geoff <geoff@invalid.invalid> - 2014-12-27 14:54 -0800
                Re: complex number in struct form in C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-27 15:45 -0800
                Re: complex number in struct form in C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-27 13:40 -0800
                Re: complex number in struct form in C James Kuyper <jameskuyper@verizon.net> - 2014-12-28 06:50 -0500
                Re: complex number in struct form in C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-28 04:25 -0800
                Re: complex number in struct form in C James Kuyper <jameskuyper@verizon.net> - 2014-12-28 06:44 -0500
                Re: complex number in struct form in C Richard Damon <Richard@Damon-Family.org> - 2014-12-28 08:33 -0500
                Re: complex number in struct form in C James Kuyper <jameskuyper@verizon.net> - 2014-12-27 11:46 -0500
                Re: complex number in struct form in C glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-12-28 07:28 +0000
                Re: complex number in struct form in C Kaz Kylheku <kaz@kylheku.com> - 2014-12-27 17:23 +0000
            Re: complex number in struct form in C James Kuyper <jameskuyper@verizon.net> - 2014-12-21 14:37 -0500
          Re: complex number in struct form in C Keith Thompson <kst-u@mib.org> - 2014-12-21 12:37 -0800
          Re: complex number in struct form in C glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-12-22 00:54 +0000
      Re: complex number in struct form in C James Kuyper <jameskuyper@verizon.net> - 2014-12-21 11:54 -0500
      Re: complex number in struct form in C Vincenzo Mercuri <nomail@yahoo.it> - 2014-12-21 18:07 +0100
        Re: complex number in struct form in C Dexterr <dejangru@gmail.com> - 2014-12-21 10:37 -0800
          Re: complex number in struct form in C "Chris M. Thomasson" <no@spam.invalid> - 2014-12-21 10:55 -0800
          Re: complex number in struct form in C raltbos@xs4all.nl (Richard Bos) - 2014-12-22 12:15 +0000
            Re: complex number in struct form in C Dexterr <dejangru@gmail.com> - 2014-12-22 05:51 -0800
              Re: complex number in struct form in C BartC <bc@freeuk.com> - 2014-12-22 14:01 +0000
                Re: complex number in struct form in C Keith Thompson <kst-u@mib.org> - 2014-12-22 08:02 -0800
            Re: complex number in struct form in C Keith Thompson <kst-u@mib.org> - 2014-12-22 08:03 -0800
    Re: complex number in struct form in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-12-21 22:27 +0000
  Re: complex number in struct form in C "Chris M. Thomasson" <no@spam.invalid> - 2014-12-21 10:51 -0800
    Re: complex number in struct form in C Dexterr <dejangru@gmail.com> - 2014-12-21 11:14 -0800
  Re: complex number in struct form in C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-21 17:17 -0800

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