def laguerre(a,tol):
x = random() # Starting value (random number)
n = len(a) - 1
for i in range(30):
p,dp,ddp = evalPoly(a,x)
if abs(p) < tol: return x
g = dp/p
h = g*g - ddp/p
f = cmath.sqrt((n - 1)*(n*h - g*g))
if abs(g + f) > abs(g - f): dx = n/(g + f)
else: dx = n/(g - f)
x = x - dx
if abs(dx) < tol: return x
print("Too many iterations")
def laguerre(a,tol):
x = random() # Starting value (random number)
n = len(a) - 1
for i in range(30):
p,dp,ddp = evalPoly(a,x)
if abs(p) < tol: return x
g = dp/p
h = g*g - ddp/p
f = sqrt((n - 1)*(n*h - g*g))
if abs(g + f) > abs(g - f): dx = n/(g + f)
else: dx = n/(g - f)
x = x - dx
if abs(dx) < tol: return x
print 'Too many iterations'