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Re: What is the greatest known Fibonacci number?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg16655] Re: What is the greatest known Fibonacci number?
  • From: Vesa-Matti Sarenius <sarenius at student.oulu.fi>
  • Date: Fri, 19 Mar 1999 12:54:05 -0500
  • Organization: University of Oulu
  • References: <7c5a5k$7op@smc.vnet.net> <7cq3oj$54i@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

> There is an implcit formula for calculating the n'th fibonacci number.
> if you mail pewei at algonet.se I think I have it somewhere.

with Mathematica MatrixPower, you can get large Fibonacci numbers fast.

fibona[n_]:=MatrixPower[{{1,1},{1,0}},n][[1,1]]

In: Timing[fibona[100000]]

Out: {2.38 Second,42026927029951543...}

On Pentium 120...

Roman Maeders book The Mathematrica Programmer discusses more about
making this algorithm more effective.

-- 
Vesa-Matti Sarenius             *  - Am I a man or what? - A What!*
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