Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > comp.lang.python > #87857

Re: fibonacci series what Iam is missing ?

Path csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!newsfeed.xs4all.nl!newsfeed1.news.xs4all.nl!xs4all!news.tele.dk!news.tele.dk!small.news.tele.dk!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail
Return-Path <davea@davea.name>
X-Original-To python-list@python.org
Delivered-To python-list@mail.python.org
X-Spam-Status OK 0.010
X-Spam-Evidence '*H*': 0.98; '*S*': 0.00; 'else:': 0.03; 'algorithm': 0.04; 'elif': 0.05; '*not*': 0.07; 'practice,': 0.07; 'subject:missing': 0.07; 'def': 0.12; 'wrote': 0.14; '24,': 0.16; '465': 0.16; 'subject: ?': 0.16; 'wrote:': 0.18; '>>>': 0.22; 'example': 0.22; 'header:User-Agent:1': 0.23; 'question': 0.24; 'possibly': 0.26; 'header:In-Reply-To:1': 0.27; 'chris': 0.29; 'am,': 0.29; 'is?': 0.30; "d'aprano": 0.31; 'steven': 0.31; 'subject:what': 0.31; 'could': 0.34; 'but': 0.35; 'version': 0.36; 'to:addr:python-list': 0.38; 'pm,': 0.38; 'to:addr:python.org': 0.39; 'how': 0.40; 'charset:windows-1252': 0.65; 'series': 0.66; 'mar': 0.68; 'received:74.208': 0.68; '2015': 0.84; 'received:74.208.4.194': 0.84; 'toy': 0.84; 'fibonacci': 0.91; 'inefficient': 0.91
Date Mon, 23 Mar 2015 20:42:07 -0400
From Dave Angel <davea@davea.name>
User-Agent Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0
MIME-Version 1.0
To python-list@python.org
Subject Re: fibonacci series what Iam is missing ?
References <CACT3xuVF-MOVQK5wSorRSAfpAQEXvS7QsqarACVZKXsQ0bxzpQ@mail.gmail.com> <mailman.72.1427127417.10327.python-list@python.org> <5510ad7a$0$12979$c3e8da3$5496439d@news.astraweb.com>
In-Reply-To <5510ad7a$0$12979$c3e8da3$5496439d@news.astraweb.com>
Content-Type text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding 7bit
X-Provags-ID V03:K0:1uIqCZcPa0i3TAwKgLFiFnofu262fsjfNGpDu9qhs2T8Ps78CkC I2fIfJHAVBGUaBu9XnyHnfhlnd3zGQG7vtJkjtjYrN2rvID+mFL0+DdJogaTY+7ibiMi17v tuf8YycO9fBVmwFG4/b2PHNnNyc85IxqgbYXSdituArLCrkkJ29IJ6DXVyAIbCVzICG8uAK HIav1cKtbCnHYYO+oUYsw==
X-UI-Out-Filterresults notjunk:1;
X-BeenThere python-list@python.org
X-Mailman-Version 2.1.19
Precedence list
List-Id General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe <https://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe>
List-Archive <http://mail.python.org/pipermail/python-list/>
List-Post <mailto:python-list@python.org>
List-Help <mailto:python-list-request@python.org?subject=help>
List-Subscribe <https://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
Newsgroups comp.lang.python
Message-ID <mailman.89.1427157732.10327.python-list@python.org> (permalink)
Lines 52
NNTP-Posting-Host 2001:888:2000:d::a6
X-Trace 1427157732 news.xs4all.nl 2940 [2001:888:2000:d::a6]:58195
X-Complaints-To abuse@xs4all.nl
Xref csiph.com comp.lang.python:87857

Show key headers only | View raw


On 03/23/2015 08:19 PM, Steven D'Aprano wrote:
> On Tue, 24 Mar 2015 03:16 am, Chris Angelico wrote about the standard
> recursive version of the Fibonacci series:
>
>> On Tue, Mar 24, 2015 at 3:01 AM, Ganesh Pal <ganesh1pal@gmail.com> wrote:
>
>>> def fib(n):
>>>      if n == 0:
>>>          return 0
>>>      elif n == 1:
>>>          return 1
>>>      else:
>>>          return fib(n-1) + fib(n-2)
>
>
>> 2) Your algorithm is about as hopelessly inefficient as it could
>> possibly be, barring deliberate intent.
>
>
> It is pretty inefficient, but it is a good toy example of recursion. It's
> also a good example of how *not* to write the Fibonacci series in practice,
> what is mathematically straightforward is not always computationally
> efficient.
>
> The question is, just how inefficient is is? How many calls to `fib` are
> made in calling fib(n)?
>
> Answer to follow.
>
>
>

0 1
1 1
2 3
3 5
4 9
5 15
6 25
7 41
8 67
9 109
10 177
11 287
12 465
13 753
14 1219



-- 
DaveA

Back to comp.lang.python | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

Re: fibonacci series what Iam is missing ? Chris Angelico <rosuav@gmail.com> - 2015-03-24 03:16 +1100
  Re: fibonacci series what Iam is missing ? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-24 11:19 +1100
    Re: fibonacci series what Iam is missing ? Dave Angel <davea@davea.name> - 2015-03-23 20:42 -0400
    Re: fibonacci series what Iam is missing ? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-24 11:56 +1100
    Re: fibonacci series what Iam is missing ? Chris Angelico <rosuav@gmail.com> - 2015-03-24 11:59 +1100
      Re: fibonacci series what Iam is missing ? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-24 12:52 +1100
        Re: fibonacci series what Iam is missing ? Rustom Mody <rustompmody@gmail.com> - 2015-03-23 19:23 -0700
        Re: fibonacci series what Iam is missing ? Chris Angelico <rosuav@gmail.com> - 2015-03-24 14:03 +1100
          Re: fibonacci series what Iam is missing ? Rustom Mody <rustompmody@gmail.com> - 2015-03-23 20:30 -0700
          Re: fibonacci series what Iam is missing ? Rustom Mody <rustompmody@gmail.com> - 2015-03-23 21:13 -0700

csiph-web