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Re: Can math.atan2 return INF?

From Gregory Ewing <greg.ewing@canterbury.ac.nz>
Newsgroups comp.lang.python
Subject Re: Can math.atan2 return INF?
Date 2016-06-28 18:12 +1200
Message-ID <dteiq1Fqu62U2@mid.individual.net> (permalink)
References (15 earlier) <87y45spgsz.fsf@elektro.pacujo.net> <dtb5jbF69muU1@mid.individual.net> <5770968a$0$1589$c3e8da3$5496439d@news.astraweb.com> <87inwvp22e.fsf@elektro.pacujo.net> <35f8e10b-abca-4f8f-9fd8-bd9be15eabad@googlegroups.com>

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Rustom Mody wrote:
> I said that for the Haskell list [0..]
> 
> [0..] ++ [-1] == [0..]
> 
> He said (in effect) yes that -1 would not be detectable but its still there!

The code to generate it is there, but it will never
be executed, so the compiler is entitled to optimise
it away. :-)

He may have a point though. There are avenues of
mathematics where people think about objects such
as "all the natural numbers, followed by -42", and
consider that to be something different from just
"all the natural numbers".

So, a mathematician would probably say they're not
equal. A scientist would say they may or may not be
equal, but the difference is not testable.

An engineer would say "Lessee, 0, 1, 2, 3, 4, 5,
6, 7... yep, they're equal to within measurement
error."

-- 
Greg

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Thread

Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-06-22 03:50 +1000
  Re: Can math.atan2 return INF? pdorange@pas-de-pub-merci.mac.com (Pierre-Alain Dorange) - 2016-06-21 20:01 +0200
    Re: Can math.atan2 return INF? Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-06-21 21:32 +0300
      Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-06-22 11:40 +1000
        Re: Can math.atan2 return INF? Nagy László Zsolt <gandalf@shopzeus.com> - 2016-06-27 15:27 +0200
    Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-06-22 11:38 +1000
      Re: Can math.atan2 return INF? pdorange@pas-de-pub-merci.mac.com (Pierre-Alain Dorange) - 2016-06-22 08:21 +0200
      Re: Can math.atan2 return INF? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-22 16:34 +0100
        Re: Can math.atan2 return INF? Random832 <random832@fastmail.com> - 2016-06-22 12:19 -0400
        Re: Can math.atan2 return INF? pdorange@pas-de-pub-merci.mac.com (Pierre-Alain Dorange) - 2016-06-22 19:18 +0200
          Re: Can math.atan2 return INF? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-22 20:17 +0100
            Re: Can math.atan2 return INF? Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-22 12:50 -0700
            Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-06-23 13:59 +1000
              Re: Can math.atan2 return INF? Dan Sommers <dan@tombstonezero.net> - 2016-06-23 04:40 +0000
                Re: Can math.atan2 return INF? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-23 16:45 +1000
                Re: Can math.atan2 return INF? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-23 15:39 +0100
                Re: Can math.atan2 return INF? alister <alister.ware@ntlworld.com> - 2016-06-23 15:04 +0000
                Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-06-24 02:44 +1000
                Re: Can math.atan2 return INF? pdorange@pas-de-pub-merci.mac.com (Pierre-Alain Dorange) - 2016-06-23 19:14 +0200
                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-23 20:22 +0300
                Re: Can math.atan2 return INF? pdorange@pas-de-pub-merci.mac.com (Pierre-Alain Dorange) - 2016-06-24 09:53 +0200
                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-24 13:38 +0300
                Re: Can math.atan2 return INF? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-26 11:43 +1200
                Re: Can math.atan2 return INF? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-26 11:40 +1200
                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-26 10:09 +0300
                Re: Can math.atan2 return INF? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-27 11:08 +1200
                Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-06-27 12:59 +1000
                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-27 09:40 +0300
                Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-06-27 06:15 -0700
                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-27 16:45 +0300
                Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-06-27 07:01 -0700
                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-27 17:12 +0300
                Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-06-27 07:27 -0700
                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-27 20:03 +0300
                Re: Can math.atan2 return INF? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-28 18:12 +1200
                Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-06-27 23:25 -0700
                Re: Can math.atan2 return INF? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-28 16:27 +1000
                Re: Can math.atan2 return INF? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-28 18:12 +1200
                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-28 09:23 +0300
                Re: Can math.atan2 return INF? Random832 <random832@fastmail.com> - 2016-06-28 09:39 -0400
                Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-06-29 01:22 +1000
                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-28 19:36 +0300
                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-28 19:42 +0300
                Re: Can math.atan2 return INF? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-29 19:35 +1000
                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-29 13:54 +0300
                Re: Can math.atan2 return INF? Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-29 18:33 -0700
                Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-06-29 19:13 -0700
                Re: Can math.atan2 return INF? Chris Angelico <rosuav@gmail.com> - 2016-06-30 12:38 +1000
                Re: Can math.atan2 return INF? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-30 18:24 +1000
                Re: Can math.atan2 return INF? Andreas Röhler <andreas.roehler@online.de> - 2016-06-30 11:35 +0200
                Re: Can math.atan2 return INF? Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-30 02:42 -0700
                Re: Can math.atan2 return INF? Andreas Röhler <andreas.roehler@online.de> - 2016-06-30 12:13 +0200
                Re: Can math.atan2 return INF? Andreas Röhler <andreas.roehler@online.de> - 2016-06-30 12:11 +0200
                Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-07-01 03:18 +1000
                Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-06-30 08:28 -0700
                Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-07-01 04:03 +1000
                Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-07-01 07:19 -0700
                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-07-01 18:20 +0300
                Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-07-29 22:46 -0700
                Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-08-01 12:53 +1000
                Re: Can math.atan2 return INF? Paul Rubin <no.email@nospam.invalid> - 2016-07-31 20:41 -0700
                Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-07-31 20:54 -0700
                Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-07-31 21:05 -0700
                Re: Can math.atan2 return INF? Ian Kelly <ian.g.kelly@gmail.com> - 2016-08-01 01:05 -0600
                Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-07-24 19:48 -0700
                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-30 09:24 +0300
                Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-06-29 23:29 -0700
                Re: Can math.atan2 return INF? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-06-30 07:47 -0400
                Re: Can math.atan2 return INF? alister <alister.ware@ntlworld.com> - 2016-06-30 14:54 +0000
                Re: Can math.atan2 return INF? Paul Rubin <no.email@nospam.invalid> - 2016-06-29 23:57 -0700
                Re: Can math.atan2 return INF? Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-30 00:16 -0700
                Re: Can math.atan2 return INF? Paul Rubin <no.email@nospam.invalid> - 2016-06-30 00:32 -0700
                Re: Can math.atan2 return INF? Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-30 00:39 -0700
                Re: Can math.atan2 return INF? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-30 18:27 +1000
                Re: Can math.atan2 return INF? Andreas Röhler <andreas.roehler@online.de> - 2016-06-30 09:17 +0200
                Re: Can math.atan2 return INF? Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-30 00:17 -0700
                Re: Can math.atan2 return INF? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-30 18:06 +1200
                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-30 09:32 +0300
                Re: Can math.atan2 return INF? Random832 <random832@fastmail.com> - 2016-06-29 09:55 -0400
                Re: Can math.atan2 return INF? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-26 11:15 +1200
                Re: Can math.atan2 return INF? MRAB <python@mrabarnett.plus.com> - 2016-06-26 00:31 +0100
                Re: Can math.atan2 return INF? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-23 20:04 +0100
                Re: Can math.atan2 return INF? pdorange@pas-de-pub-merci.mac.com (Pierre-Alain Dorange) - 2016-06-23 19:07 +0200
              Re: Can math.atan2 return INF? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-23 15:37 +0100

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