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fibo2.py
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fibo2.py
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#!/usr/bin/env python
# -*- coding: utf-8 -*-
import math
import numpy as np
import matplotlib.pyplot as plt
# compute Fibonacci numbers (accelerated using memoization)
class Fibo:
memo = {}
def __init__(self):
pass
def __call__(self, k):
if k in self.memo:
return self.memo[k]
k = int(k)
if k < 0:
raise ValueError("out of domain; k must be >= 0, got %d" % (k))
out = None
if k < 2:
out = k
else:
out = self(k-1) + self(k-2)
self.memo[k] = out
return out
def main():
f = Fibo()
numbers = [ f(j) for j in range(1000) ]
print(numbers)
minf = float("-inf")
L = [ (math.log10(n) if n > 0 else minf) for n in numbers ]
print(L)
print( np.diff(L) )
plt.figure(1)
plt.clf()
plt.plot(L)
plt.xlabel(r"$n$")
plt.ylabel(r"$\log_{10}( \mathrm{fib}(n) )$")
plt.title("Fibonacci numbers (logarithmic scale)")
if __name__ == '__main__':
main()
plt.show()