anum/Chapitre1-Bissection.ipynb

In [1]:

import numpy as np
import matplotlib.pyplot as plt

In [2]:

def f(x):
    return 4*x**3 - 24*x**2 + 48*x - 32

In [3]:

def bissection(interval, f, tolerance=1e-5):
    x = (interval[1]+interval[0])/2
    fx = f(x)
    while abs(fx) > tolerance:
        if f(interval[0]) > 0 and fx > 0:
            interval = [x,interval[1]]
        else:
            interval = [interval[0],x]
        x = (interval[1]+interval[0])/2
        fx = f(x)
    return x

In [4]:

xs = np.arange(0,4,0.1)
ys = np.array(f(xs))
root=bissection([1,3],f)
plt.plot(xs,ys,'r')
plt.plot(root,0,'.b')

Out[4]:

[<matplotlib.lines.Line2D at 0x2724b268090>]

In [ ]: