用Python实现的代价函数: **谢谢你的帮助。你知道吗
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
load_data = pd.read_csv('C:\python_program\ex1data1.txt',sep = ",",header = None)
feature_vale = load_data[0]
y = np.matrix(load_data[1])
m = len(feature_vale)
plt.scatter(load_data[0],load_data[1],marker='+',c = 'r')
plt.title("Cost_Function")
plt.xlabel("Population of City in 10,000s")
plt.ylabel("Profit in $10,000s")
df = pd.DataFrame(pd.Series(1,index= range(0,m)))
df[1] = load_data[0]
X = np.matrix(df)
row_theta = np.zeros(2,dtype = int)
theta = np.array([row_theta]) # Transpose the array
prediction = np.dot(X,theta.T)
error = (prediction-y.T)
error_df = pd.DataFrame(error)
#square the error
squared_error = np.square(error_df)
sum = np.sum(squared_error)
print(sum)
J = np.sum(squared_error) / (2 * m)
print(J)
数据参考链接:searchcode.com/codesearch/view/5404318你知道吗
重复以下步骤并通知我
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