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Re: Fibonacci series recursion error

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From Ian Kelly <ian.g.kelly@gmail.com>
Date Tue, 3 May 2011 16:31:29 -0600
Subject Re: Fibonacci series recursion error
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On Tue, May 3, 2011 at 3:41 PM, Chris Angelico <rosuav@gmail.com> wrote:
> On Wed, May 4, 2011 at 3:10 AM, harrismh777 <harrismh777@charter.net> wrote:
>> If your point is that the infinite process is the problem, I agree. But my
>> point is that the cpu crunch and the rate at which the call stack is filled
>> has to do with the double call (which never finds tail processing).
>
> The double call _does not_ affect it. Failing to terminate recursion
> _does_. I don't know what you mean by "cpu crunch" but the call stack
> is going to get n entries. On the Python 2.6 on this system,
> sys.getrecursionlimit() returns 1000, meaning that you can calculate
> fib(1000) safely (okay, probably not quite as there'll be a few used
> for other things, but fib(900) would be safe).

Depends what you mean by "safe".  A back-of-the-envelope calculation
shows that with modern technology it would take more than 10 ** 257
years to complete.  That puts it well into the Dark Era of the
universe, long after the black holes will have decayed, when I suspect
it will be difficult to find a continued power source for the computer
to run.  And even if it somehow is still running, the process memory
will have been so thoroughly muddled by cosmic rays that the final
result of the calculation will be utterly worthless.

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Thread

Fibonacci series recursion error lalit <opposite800@gmail.com> - 2011-04-29 20:22 -0700
  Re: Fibonacci series recursion error Gary Herron <gherron@islandtraining.com> - 2011-04-29 20:41 -0700
  Re: Fibonacci series recursion error Jason Friedman <jason@powerpull.net> - 2011-04-30 03:57 +0000
  Re: Fibonacci series recursion error harrismh777 <harrismh777@charter.net> - 2011-04-29 23:45 -0500
    Re: Fibonacci series recursion error harrismh777 <harrismh777@charter.net> - 2011-04-29 23:51 -0500
      Re: Fibonacci series recursion error harrismh777 <harrismh777@charter.net> - 2011-04-30 00:31 -0500
        Re: Fibonacci series recursion error Peter Otten <__peter__@web.de> - 2011-04-30 08:14 +0200
          Re: Fibonacci series recursion error rusi <rustompmody@gmail.com> - 2011-05-02 00:08 -0700
    Re: Fibonacci series recursion error Hans Georg Schaathun <hg@schaathun.net> - 2011-04-30 06:50 +0100
    Re: Fibonacci series recursion error Paul Rudin <paul.nospam@rudin.co.uk> - 2011-04-30 06:43 +0100
  Re: Fibonacci series recursion error Ian Kelly <ian.g.kelly@gmail.com> - 2011-04-29 23:27 -0600
    Re: Fibonacci series recursion error harrismh777 <harrismh777@charter.net> - 2011-04-30 00:35 -0500
      Re: Fibonacci series recursion error Peter Otten <__peter__@web.de> - 2011-04-30 08:32 +0200
        Re: Fibonacci series recursion error Chris Angelico <rosuav@gmail.com> - 2011-04-30 16:37 +1000
      Re: Fibonacci series recursion error Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2011-04-30 11:37 +0200
        Re: Fibonacci series recursion error harrismh777 <harrismh777@charter.net> - 2011-05-02 16:50 -0500
          Re: Fibonacci series recursion error Chris Angelico <rosuav@gmail.com> - 2011-05-03 08:17 +1000
            Re: Fibonacci series recursion error harrismh777 <harrismh777@charter.net> - 2011-05-03 12:10 -0500
              Re: Fibonacci series recursion error Chris Angelico <rosuav@gmail.com> - 2011-05-04 07:41 +1000
              Re: Fibonacci series recursion error Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-03 16:31 -0600
              Re: Fibonacci series recursion error Chris Angelico <rosuav@gmail.com> - 2011-05-04 09:09 +1000
          Re: Fibonacci series recursion error Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-02 16:22 -0600
          Re: Fibonacci series recursion error Chris Angelico <rosuav@gmail.com> - 2011-05-03 08:42 +1000
          Recursion or iteration (was Fibonacci series recursion error) rusi <rustompmody@gmail.com> - 2011-05-02 18:48 -0700
            Re: Recursion or iteration (was Fibonacci series recursion error) Chris Angelico <rosuav@gmail.com> - 2011-05-03 12:13 +1000
            Re: Recursion or iteration (was Fibonacci series recursion error) Chris Angelico <rosuav@gmail.com> - 2011-05-03 15:29 +1000
              Re: Recursion or iteration (was Fibonacci series recursion error) rusi <rustompmody@gmail.com> - 2011-05-03 00:52 -0700
                Re: Recursion or iteration (was Fibonacci series recursion error) Dave Angel <davea@ieee.org> - 2011-05-03 06:32 -0400
                Re: Recursion or iteration (was Fibonacci series recursion error) rusi <rustompmody@gmail.com> - 2011-05-03 03:51 -0700
                Re: Recursion or iteration (was Fibonacci series recursion error) Chris Angelico <rosuav@gmail.com> - 2011-05-03 21:04 +1000
                Re: Recursion or iteration (was Fibonacci series recursion error) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-03 12:49 +0000
                Re: Recursion or iteration (was Fibonacci series recursion error) Chris Angelico <rosuav@gmail.com> - 2011-05-03 23:02 +1000
                Re: Recursion or iteration (was Fibonacci series recursion error) Hans Mulder <hansmu@xs4all.nl> - 2011-05-12 00:06 +0200
                Re: Recursion or iteration (was Fibonacci series recursion error) rusi <rustompmody@gmail.com> - 2011-05-13 04:11 -0700
                Re: Recursion or iteration (was Fibonacci series recursion error) Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-13 07:55 -0600
                Re: Recursion or iteration (was Fibonacci series recursion error) Hans Mulder <hansmu@xs4all.nl> - 2011-05-13 21:46 +0200
                Re: Recursion or iteration (was Fibonacci series recursion error) Mark Dickinson <dickinsm@gmail.com> - 2011-05-13 14:48 -0700
                Re: Recursion or iteration (was Fibonacci series recursion error) rusi <rustompmody@gmail.com> - 2011-05-14 10:24 -0700
                Re: Recursion or iteration (was Fibonacci series recursion error) Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-14 15:19 -0600
                Re: Recursion or iteration (was Fibonacci series recursion error) rusi <rustompmody@gmail.com> - 2011-05-14 20:32 -0700
                Re: Recursion or iteration (was Fibonacci series recursion error) Mark Dickinson <dickinsm@gmail.com> - 2011-05-15 12:20 -0700
                Re: Recursion or iteration (was Fibonacci series recursion error) Mark Dickinson <dickinsm@gmail.com> - 2011-05-15 12:29 -0700
            Re: Recursion or iteration (was Fibonacci series recursion error) Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-02 23:46 -0600

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