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From: David Kastrup <dak@gnu.org>
Subject: Re: to big nest level of recursion
Date: Sat, 25 Mar 2006 12:46:40 +0100	[thread overview]
Message-ID: <85mzfe21cv.fsf@lola.goethe.zz> (raw)
In-Reply-To: 94630e.09.ln@acm.acm

Alan Mackenzie <acm@muc.de> writes:

> David Reitter <david.reitter@gmail.com> wrote on Tue, 21 Mar 2006
> 21:31:29 +0000:
>
> [ .... ]
>
>> Maybe it's a consolation for you that for every recursive algorithm,
>> you can formulate an iterative version. And you don't bloat a call
>> stack when you do so.
>
> This is not true.  There are algorithms that are intrinsically
> recursive and cannot be formulated with mere iteration (such as the
> Ackermann function, specially invented to demonstrate this).

They cannot be formulated with iteration _without_ a stack.  But of
course, when using a stack as a data structure, you can map any
recursion onto iteration.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum

  reply	other threads:[~2006-03-25 11:46 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <mailman.21.1142976703.14011.help-gnu-emacs@gnu.org>
2006-03-25 10:30 ` to big nest level of recursion Alan Mackenzie
2006-03-25 11:46   ` David Kastrup [this message]
2006-04-04 13:36     ` david.reitter
2006-03-21 21:31 David Reitter
  -- strict thread matches above, loose matches on Subject: below --
2006-03-20 12:35 Anton V. Belyaev
2006-03-20 12:45 ` Hans-Christoph Wirth
2006-03-20 12:51 ` David Kastrup
2006-03-20 13:52 ` Pascal Bourguignon
2006-03-20 15:56   ` Anton V. Belyaev
2006-03-21 17:09     ` Stefan Monnier

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