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Fibonacci

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Fibonacci

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The following function generate the fibinacci series up to the sequence number m.

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Description

The following function generate the fibinacci series up to the sequence number m which should be a positive integer, it may takes several minutes for big numbers of m, for a typical working station m>20 is taking considerable amount of time to be processed.

Feel free to contact us for any furthur information:
 {hasan.demirel, shahab.jafari}@emu.edu.tr
  http://faraday.ee.emu.edu.tr/shahab
  http://faraday.ee.emu.edu.tr/hdemirel
  (c) Demirel and Anbarjafari -2008

MATLAB release MATLAB 7.5 (R2007b)
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Comments and Ratings (19)
08 Feb 2011 Jennifer Galt

Jennifer Galt

Poor. Terribly inefficient, even for a beginner.

24 Apr 2009 Xu Wings

Xu Wings

 
15 Apr 2009 Mustafa

Mustafa

 
05 Apr 2009 Robin Torres

Robin Torres

 
05 Apr 2009 Xing Yu

Xing Yu

 
05 Apr 2009 alain boyer

alain boyer

 
05 Apr 2009 V. Poor

V. Poor

 
02 Apr 2009 Kemal

Kemal

 
01 Apr 2009 Gholamreza (Šahab) Anbarjafari

:)

Comment only
31 Mar 2009 Hal 9000

Hal 9000

poorly written

30 Mar 2009 Kemal

Kemal

 
25 Mar 2009 Xu Wings

Xu Wings

not so professional

21 Dec 2008 Derek O'Connor

Derek O'Connor

This is a very poor example for demonstrating recursion and my lead naive students to believe that all recursion is inefficient.

This is not true: the recursive Fibonacci generator is a classic example of using a good tool for the wrong job.

For example, fibonacci(25) makes 243,028 fibonacci() calls, all but 25 of them superfluous.

If you really need to calculate Fibonacci numbers then something such as the following function will be much faster.

function result = IFib(n);
F0 = 0;
F1 = 1;
for k = 2:n
F2 = F1 + F0;
F0 = F1;
F1 = F2
end;
result = F2;

If you need to demonstrate recursion to students then choose a better example, such as Binary Search of an ordered table. Many more examples can be found in any good book on algorithms.

Derek O'Connor

Comment only
14 Dec 2008 Jeff Burkey

Jeff Burkey

Shahab, cyclonic programming is the most cpu time intensive technique (i.e. slow). I would like to make the suggestion, why not teach your students multi-dimensional techniques which is what Matlab excels at best for a platform and is orders of magnitude faster. That said, working with large datasets certainly may require loops, or at best a combination of loops and dimensional math. Plus if you go parallel processing deminsonal math would be prefered. Regards, Jeff.

Comment only
13 Dec 2008 Gholamreza (Šahab) Anbarjafari

Thanks for your comment Jos, well the reason that I post this file was some of my students want an example of using a recursive function MATLAB, so I let them have it by posting it here, not only them but maybe some other people may want to just have a review of recursive function.
I appreciate you sparing your time on commenting my programme.

Comment only
13 Dec 2008 Jos (10584)

Jos (10584)

There are so many ways to arrive at a fibonacci number: see http://blogs.mathworks.com/loren/2006/05/17/fibonacci-and-filter/

This submission is not so bad in itself, although the help lacks an H1 line (used by LOOKFOR) and an example. However, as this is clearly a product of a programming exercise, I do not think this is worthwhile to post it here on the FEX. Hence my 2 stars.

13 Dec 2008 i posh

i posh

Shahab, thanks for the example....

12 Dec 2008 alain boyer

alain boyer

 
12 Dec 2008 Anon

Anon

Why going for recursion, when there are other ways to solve it?

Your function:
>>tic;a = fibonacci(30);toc
Elapsed time is 57.611550 seconds.
>> a

a =

832040

David Terr's function
http://www.mathworks.com/matlabcentral/fileexchange/5093

>> tic;a = fibonacci2(30);toc
Elapsed time is 0.000082 seconds.
>> a

a =

832040

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