def pol1(x, a):
"""
Algoritmo pol1
"""
n = a.shape[0]
px = a[n-1]
for j in range(n-2, -1, -1):
px = px + a[j] * x**(n-j-1)
return px
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def pol2(x, a):
"""
Algoritmo pol2
"""
n = a.shape[0]
px = a[n-1]
xp = 1
for j in range(n-2, -1, -1):
xp = xp*x
px = px + a[j] * xp
return px
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def horner(x, a):
"""
Algoritmo di Horner
"""
n = a.shape[0]
px = a[0]
for i in range(1, n):
px = a[i] + px*x
return px
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import numpy as np
import matplotlib.pylab as plt
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p = np.array([1,-6,15,-20,15,-6,1])
x = np.linspace(0.995,1.005,1000)
# rappresentazione compatta
y = (x-1)**6
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# Algoritmo di horner
yh = horner(x,p)
# Algoritmo 1
y1 = pol1(x,p)
# Algoritmo 2
y2 = pol2(x,p)
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plt.plot(x,y,'-b',lw=2)
plt.plot(x,yh,'og')
plt.plot(x,y1,'*r')
plt.plot(x,y2,'vm')
plt.savefig('polfig.png')
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