Fibonacci Sequence Calculation

The following page provides an example of calculating the Fibonacci Sequence, and performance profiling it.

Setup

Since we want to performance profile the calculation, we first enable the performance timer, of 'program execution only'.

LUA

$ cmd
/ cycle|timeprompt
[    15.951] / cycle|timeprompt
[     0.000] / cycle|timeprompt
[     0.000] / exit
[     0.000] $

After running the above, the time prompt should be a light blue / cyan color (this indicates the performance timer of ‘program execution only’).

Script

Lets first define the Fibonacci function, naming it accordingly.

The prompt has been omitted from the following snippet in order to allow the user to copy-paste it with ease.

LUA

function FiboNonRecursive(n)
     a = 0
     b = 1
     c = (n >> 1)
     for i=1,c do
         a=a+b
         b=a+b
     end
     if (n & 1) == 1 then
         return b;
     else
         return a;
     end
end

Next, lets call it!

LUA

[     0.000] $ FiboNonRecursive(35)
9227465
[ #1 ] [     0.004] $

Summary

So the 35th series of the Fibonacci sequence is equal to 9227465 was calculated in 4 milliseconds.

References

Command Mode

fibonacci_nonrecursive.lua