38 lines
981 B
Python
38 lines
981 B
Python
import numpy as np
|
|
import math
|
|
import matplotlib.pyplot as plt
|
|
|
|
# Adatok előállítása
|
|
x = np.linspace(-math.pi, math.pi, 2000)
|
|
y = np.sin(x)
|
|
|
|
# Véletlen súlyok
|
|
a = np.random.randn()
|
|
b = np.random.randn()
|
|
c = np.random.randn()
|
|
d = np.random.randn()
|
|
|
|
learning_rate = 1e-6
|
|
for t in range(2000):
|
|
y_pred = a + b * x + c * x ** 2 + d * x ** 3
|
|
loss = np.square(y_pred - y).sum()
|
|
grad_y_pred = 2.0 * (y_pred - y)
|
|
grad_a = grad_y_pred.sum()
|
|
grad_b = (grad_y_pred * x).sum()
|
|
grad_c = (grad_y_pred * x ** 2).sum()
|
|
grad_d = (grad_y_pred * x ** 3).sum()
|
|
a -= learning_rate * grad_a
|
|
b -= learning_rate * grad_b
|
|
c -= learning_rate * grad_c
|
|
d -= learning_rate * grad_d
|
|
|
|
# Ábrázolás
|
|
plt.plot(x, y, label='Szinusz függvény')
|
|
plt.plot(x, a + b * x + c * x ** 2 + d * x ** 3, label='Tanult polinom', linestyle='--')
|
|
plt.xlabel('x')
|
|
plt.ylabel('y')
|
|
plt.title('Szinusz és tanult polinom összehasonlítása')
|
|
plt.legend()
|
|
plt.grid(True)
|
|
plt.show()
|