# Data
import numpy as np
import tensorflow as tf
# data
X_raw = np.array([2013, 2014, 2015, 2016, 2017], dtype=np.float32)
y_raw = np.array([12000, 14000, 15000, 16500, 17500], dtype=np.float32)
# 归一化
X = (X_raw - X_raw.min()) / (X_raw.max() - X_raw.min())
y = (y_raw - y_raw.min()) / (y_raw.max() - y_raw.min())
X = tf.constant(X)
y = tf.constant(y)
a = tf.Variable(initial_value=0.)
b = tf.Vari