作業中的 Momentum 題目是否給錯方向? - Cupoy

作業中的 Momentum 題目是否給錯方向?

作業裡面最後一題跟詳解給的似乎是不同的 Q 和 A 吧？ 不知我這樣做對嗎？ ```python def GD_momentum(w_init, df, epochs, lr, beta): xs = np.zeros(epochs+1) x = w_init xs[0] = x v = 0 for i in range(epochs): dx = df(x) v = beta * v - lr * dx x += v xs[i+1] = x return xs line_x = np.linspace(-5, 5, 100) line_y = func(line_x) plt.figure('Gradient Descent: Momentum', figsize=(15, 4)) w_init = 3 lr = 0.1 epochs = 20 x = w_init beta = [0.1, 0.5, 0.9] color = ['r', 'g', 'y'] size = np.ones(epochs+1) * 10 size[-1] = 70 for i in range(len(beta)): x = GD_momentum(w_init, dfunc, epochs, lr, beta[i]) plt.subplot(1, 3, i+1) plt.plot(line_x, line_y, c='b') plt.plot(x, func(x), c=color[i], label='beta={}'.format(beta[i])) plt.scatter(x, func(x), c=color[i]) plt.legend() plt.grid() plt.tight_layout() plt.show() ```