梯度下降(Gradient Descent)
来源:互联网 发布:淘宝开旗舰店费用 编辑:程序博客网 时间:2024/05/17 08:24
1.基本思想简介
http://www.cnblogs.com/LeftNotEasy/archive/2010/12/05/mathmatic_in_machine_learning_1_regression_and_gradient_descent.html
2.一个简例
一个通过迭代求解convex function最小值的方法: Gradient descent(梯度下降法)
http://en.wikipedia.org/wiki/Gradient_descent
这里给出一个python的代码:
The gradient descent algorithm is applied to find a local minimum of the function f(x)=x4-3x3+2 , with derivative f'(x)=4x3-9x2. Here is an implementation in the Python programming language.
# From calculation, we expect that the local minimum occurs at x=9/4
xOld = 0
xNew = 6 # The algorithm starts at x=6
eps = 0.01 # step size
precision = 0.00001
def f_prime(x):
return 4 * x**3 - 9 * x**2
while abs(xNew - xOld) > precision:
xOld = xNew
xNew = xOld - eps * f_prime(xNew)
print("Local minimum occurs at ", xNew)
xOld = 0
xNew = 6 # The algorithm starts at x=6
eps = 0.01 # step size
precision = 0.00001
def f_prime(x):
return 4 * x**3 - 9 * x**2
while abs(xNew - xOld) > precision:
xOld = xNew
xNew = xOld - eps * f_prime(xNew)
print("Local minimum occurs at ", xNew)
3.线性回归和批量梯度下降法python
http://www.cnblogs.com/Key-Ky/archive/2013/12/10/3468290.html
0 0
- 梯度下降(gradient descent)
- 梯度下降(Gradient descent)
- 梯度下降(Gradient Descent)
- 梯度下降(Gradient Descent)
- 梯度下降(gradient descent)
- 梯度下降(Gradient Descent)
- 梯度下降(Gradient Descent)
- 梯度下降(Gradient Descent)
- 梯度下降(Gradient Descent)
- 梯度下降(Gradient Descent)
- 梯度下降(Gradient Descent)
- 梯度下降Gradient descent
- 梯度下降算法(Gradient descent)
- 梯度下降法(Gradient Descent)
- 梯度下降法(Gradient Descent)
- 梯度下降(Gradient Descent)小结
- 梯度下降(Gradient Descent)小结
- 梯度下降(Gradient Descent)小结
- Linux--基础
- ****************本文是Lua编写的游戏接入多盟SDK*******************
- HDU 1009 FatMous'Trade(贪心)
- POJ 2975 Nim(nim博弈)
- ORACLE 创建和管理表
- 梯度下降(Gradient Descent)
- 拓扑排序模板
- 深入浅出ShellExecute
- 黑马程序员_面向对象(3)_(异常)
- SwipeRefreshLayout实现下拉刷新、上拉加载更多功能
- c/C++程序占用的内存部分
- XMLConfig
- Kth Largest Element in an Array
- hdu5391 Zball in Tina Town