# 0~2π角度对应(X,Y)拟合圆 并保存训练结果
import numpy as np
import tensorflow as tf
from tensorflow import keras
import matplotlib.pyplot as plt
x = np.random.rand(1000) * 2 * np.pi
x = x.reshape([1000, 1])
y = np.hstack((np.cos(x).reshape([1000, 1]), np.sin(x).reshape([1000, 1])))
model = tf.keras.Sequential()
# 神经元个数越多,效果会越好,收敛越快,太少的话难以收敛到所需曲线
model.add(keras.layers.Dense(1000, activation='relu'))
# linear,relu,tanh, sigmoid, softmax
model.add(keras.layers.Dense(2, activation='tanh'))
model.compile(optimizer=tf.keras.optimizers.Adam(learning_rate=0.001),
loss=tf.keras.losses.mse)
model.fit(x, y, batch_size=10, epochs=100, shuffle=True, verbose=2)
plt.plot(y[:, 0], y[:, 1], "b^", label="f(x)")
py = model.predict(x)
plt.plot(py[:, 0], py[:, 1], "r.", label="predict")
plt.legend(loc=0)
plt.show()
# Save the model
# serialize model to JSON
model_digit_json = model.to_json()
with open("model_circle.json", "w") as json_file:
json_file.write(model_digit_json)
# serialize weights to HDF5
model.save("model_circle.h5")
model.save_weights("model_circle_weights.h5")
# 第二种载入方法:同时载入模型及训练好的参数
import numpy as np
from tensorflow import keras as tk
import matplotlib.pyplot as plt
x = np.random.rand(1000) * 2 * np.pi
x = x.reshape([1000, 1])
model = tk.models.load_model("model_circle.h5")
py = model.predict(x)
plt.plot(py[:, 0], py[:, 1], "r.", label="predict")
plt.legend(loc=0)
plt.show()