原标题:机器学习之线性回归使用Python和tensorflow实现
原文来自:博客园 原文链接:http://www.xinhuanet.com/2019-09/09/c_1124976366.htm
导入依赖包
import tensorflow as tf
import numpy as np
import matplotlib.pylab as pltfrom pylab
import mplmpl.rcParams['font.sans-serif'] = ['SimHei']
生成直线数据并加入噪音画图显示
train_x = np.linspace(-1, 1, 100) # 生成 -1 到 1之间 分成100份
# print(train_x)noise = np.random.randn(*train_x.shape) * 0.3
train_y = 2 * train_x + noise # 给每一个点加上噪音
# print(noise)plt.plot(train_x, train_y, "go", label="我的初始数据")
plt.legend()
plt.show()
定义模型的输入和输出
x = tf.placeholder("float")
y = tf.placeholder("float")
# 定义并初始化模型的权重偏置
w = tf.Variable(tf.random_normal([1]), name="weight")
b = tf.Variable(tf.zeros([1]), name="bias")
# 定义模型的前向传播过程y_predict = tf.multiply(w, x) + b
定义模型的损失函数,反向传播
cost = tf.reduce_mean(tf.square(y - y_predict))
learning_rate = 0.01 # 定义学习率
optimizer = tf.train.GradientDescentOptimizer(learning_rate).minimize(cost) # 定义优化器
init = tf.global_variables_initializer()
定义超参数
train_epochs = 100
display_epoch = 2
训练模型
with tf.Session() as sess:
sess.run(init)
plotdata = {"epochs": [], "cost": []} # 保存训练得到的参数
for epoch in range(train_epochs): for X, Y in zip(train_x, train_y):
sess.run(optimizer, feed_dict={x: X, y: Y}) if epoch % display_epoch == 0:
print("训练的epoch为:%d cost为:%f %f" % (epoch+1, sess.run(cost, feed_dict={x: train_x, y: train_y}), sess.run(b)))
plotdata["epochs"].append(epoch+1)
plotdata["cost"].append(sess.run(cost, feed_dict={x: train_x, y: train_y}))
print("训练完成")
print("模型训练的结果为: ", "w", sess.run(w), "b:", sess.run(b), "cost:",
sess.run(cost, feed_dict={x: train_x, y: train_y}))
画图显示
plt.plot(train_x, train_y, "go", label="我的初始数据")
plt.plot(train_x, sess.run(w) * train_x + sess.run(b), label='Fitted line')
plt.legend()
plt.show()
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