PythonPaddlePaddle机器学习之求解线性模型

def calculate_fee(distance_travelled):
    return 10+ 2*distance_travelled
for x in [1.0, 3.0, 5.0, 9.0, 10.0, 20.0]:
    print(calculate_fee(x))

import paddle
import numpy
x_data = paddle.to_tensor([[1.0], [3.0], [5.0], [9.0], [10.0], [20.0]])
y_data = paddle.to_tensor([[12.0],[16.0],[20.0],[28.0],[30.0],[50.0]])

linear = paddle.nn.Linear(in_features=1,out_features=1)

# 随机初始化w,b
w_before_opt = linear.weight.numpy().item()
b_before_opt = linear.bias.numpy().item()
# 打印初始w,b
print(w_before_opt,b_before_opt)

mse_loss = paddle.nn.MSELoss()
sgd_optimizer = paddle.optimizer.SGD(learning_rate=0.001, parameters=linear.parameters())

total_epoch = 5000

for i in range(total_epoch):
    y_predict = linear(x_data)
    loss = mse_loss(y_predict,y_data)

    # 反向传播（求梯度）
    loss.backward()
    # 优化器往前走一步：求出的梯度给优化器用调参
    sgd_optimizer.step()
    # 优化器把调完参数所用的梯度去清掉，下次再去求
    sgd_optimizer.clear_gradients()

    # 打印信息
    if i % 1000 == 0:
        print(i,loss.numpy())
print("finish training, loss = {}".fORMat(loss.numpy()) )

w_after_opt = linear.weight.numpy().item()
b_after_opt = linear.bias.numpy().item()
print(w_after_opt,b_after_opt)