numpy.linalg.eig
2024-09-21 18:27:00
1、转置对于二维数组有用，对一位数组无效
2、理解特征值和特征向量的对应关系
a=np.array([[1 ,2, 3],[4, 5, 6],[7, 8, 9]]) a
Out[27]:
array([[1, 2, 3],
[4, 5, 6],
[7, 8, 9]]) w,v = LA.eig(a) w
Out[29]: array([ 1.61168440e+01, -1.11684397e+00, -1.30367773e-15]) v
Out[30]:
array([[-0.23197069, -0.78583024, 0.40824829],
[-0.52532209, -0.08675134, -0.81649658],
[-0.8186735 , 0.61232756, 0.40824829]]) a
Out[31]:
array([[1, 2, 3],
[4, 5, 6],
[7, 8, 9]]) #dot(a[:,:], v[:,i]) = w[i] * v[:,i] w[0]
Out[33]: 16.116843969807043 v[:,0]
Out[34]: array([-0.23197069, -0.52532209, -0.8186735 ]) w[0]*v[:,0]
Out[35]: array([ -3.73863537, -8.46653421, -13.19443305]) np.dot(a[:,:],v[:,0])
Out[37]: array([ -3.73863537, -8.46653421, -13.19443305]) a
Out[38]:
array([[1, 2, 3],
[4, 5, 6],
[7, 8, 9]]) v[:,0]
Out[39]: array([-0.23197069, -0.52532209, -0.8186735 ]) 1*-0.23197069+2*-0.52532209+3*-0.8186735
Out[40]: -3.73863537 4*-0.23197069+5*-0.52532209+6*-0.8186735
Out[41]: -8.46653421 v[:,0]
Out[42]: array([-0.23197069, -0.52532209, -0.8186735 ]) v[:,0].T
Out[43]: array([-0.23197069, -0.52532209, -0.8186735 ]) w[0]
Out[44]: 16.116843969807043 w[0]*v[:,0]
Out[45]: array([ -3.73863537, -8.46653421, -13.19443305]) a
Out[46]:
array([[1, 2, 3],
[4, 5, 6],
[7, 8, 9]]) a.T
Out[47]:
array([[1, 4, 7],
[2, 5, 8],
[3, 6, 9]])
c = v[0] c
Out[49]: array([-0.23197069, -0.78583024, 0.40824829]) c.T
Out[50]: array([-0.23197069, -0.78583024, 0.40824829])
a
Out[55]:
array([[1, 2, 3],
[4, 5, 6],
[7, 8, 9]]) a*v[:,0]
Out[56]:
array([[-0.23197069, -1.05064419, -2.4560205 ],
[-0.92788275, -2.62661047, -4.912041 ],
[-1.62379481, -4.20257675, -7.36806149]]) v[:,0]
Out[57]: array([-0.23197069, -0.52532209, -0.8186735 ])
y = a*v[:,0] y
Out[59]:
array([[-0.23197069, -1.05064419, -2.4560205 ],
[-0.92788275, -2.62661047, -4.912041 ],
[-1.62379481, -4.20257675, -7.36806149]]) np.sum(y[0,:])
Out[63]: -3.7386353719172973 np.sum(y[1,:])
Out[64]: -8.4665342116284013 np.sum(y[2,:])
Out[65]: -13.194433051339505
最新文章
- Lab_7_Automating_v2.5
- java编程思想读书笔记三（11-21）
- URAL 1966 Cycling Roads 点在线段上、线段是否相交、并查集
- iOS项目上传到AppStore步骤流程
- 个人博客实现Archives查询小记
- Android实现网络多线程文件下载
- 在WWDC 2014上，没提到的iOS 8 八大新特性
- 如何解决C#编译中"csc不是内部或外部命令"的问题
- binaryTree:普通二叉树
- 3. SQL Server数据库状态监控 - 可用空间
- 使用SSD检测框架训练自己的数据
- 前端AES解密
- hello 2019 D
- jenkins中如何实现执行脚本时的变量共享
- [转]系统架构演变--集中式架构-垂直拆分-分布式服务-SOA(服务治理)-微服务
- 转载：SDWebImage支持URL不变时更新图片内容
- LeetCode35.搜索插入位置
- [PC]PHPCMS v9.5.6整合UEditer1.4.2
- nodejs中.npmrc文件的内容
- 记住，永远不要在MySQL中使用“utf8”编码[转载]