Metodo di bisezione

def f(x): return 1/3*x**3-5/3*x**2+2*x
 
a = 2.5
b = 4

fa = f(a)
fb = f(b)

for i in range(5):
    m  = (a+b)/2
    fm = f(m)

    print("%10.6f %10.6f %10.6f %10.6f %10.6f %10.6f" %(a,m,b, fa,fm,fb))
    
    if(fm == 0):
        print("Successo!")
        break
    elif(fa*fm > 0):
        a  = m
        fa = fm
    elif(fb*fm > 0):
        b  = m
        fb = f(m)
    else:
        print("Errore...")
        break
 
print()
print("La soluzione è", m)

def f(x): return 1/3*x**3-5/3*x**2+2*x
 
a = 2.5
b = 4

fa = f(a)
fb = f(b)

ERRORE = 0.01
errore = 1.0
while(errore > ERRORE):
    m      = (a+b)/2
    fm     = f(m)
    errore = b-m

    print("%10.6f %10.6f %10.6f %10.6f %10.6f %10.6f %10.6f" %(a,m,b, errore, fa,fm,fb))
    
    if(fm == 0):
        print("Successo!")
        break
    elif(fa*fm > 0):
        a  = m
        fa = fm
    elif(fb*fm > 0):
        b  = m
        fb = f(m)
    else:
        print("Errore...")
        break
 
print()
print("La soluzione è", m)

import matplotlib.pyplot as plt 
 
def f(x): return 1/3*x**3-5/3*x**2+2*x 
 
PASSI=7
I=range(PASSI) 

A=[] 
B=[] 
M=[] 
 
a =2.5
b =4
fa=f(a) 
fb=f(b) 
 
for i in range(PASSI): 
    m      = (a+b)/2
    fm     = f(m)
    errore = b-m

    print("%10.6f %10.6f %10.6f %10.6f %10.6f %10.6f %10.6f" %(a,m,b, errore, fa,fm,fb)) 

    A.append(a)
    B.append(b)
    M.append(m)

    if(fm == 0): 
        print("Successo!") 
        break
    elif(fa*fm > 0): 
        a  = m
        fa = fm        
    elif(fb*fm > 0): 
        b  = m
        fb = fm        
    else: 
        print("Errore...") 
        break
 
print()
print("La soluzione è", m) 
 
plt.plot(I, A, label="a", linewidth="2") 
plt.plot(I, M, label="m", linewidth="3") 
plt.plot(I, B, label="b", linewidth="2") 
plt.title("Metodo di bisezione") 
plt.xlabel("Soluzione") 
plt.ylabel("Passo") 
plt.grid(True) 
plt.legend() 
plt.show()

...
plt.plot(A, I, label="a", linewidth="2") 
plt.plot(M, I, label="m", linewidth="3") 
plt.plot(B, I, label="b", linewidth="2") 
...