Python伪逆和向量的行列式

时间:2013-04-08 19:22:14

标签: python vector numpy pandas linear-algebra

如何计算向量的伪逆和行列式? (最好有numpy或更好的熊猫)

我尝试了这个,但它不起作用:

import numpy
vect = [1, 2, 3, 4]
numpy.linalg.pinv(vect)

但是我收到了这个错误:

---------------------------------------------------------------------------
LinAlgError                               Traceback (most recent call last)
<ipython-input-106-e362654e383f> in <module>()
     19 vect = [1, 2, 3, 4]
---> 20 print(np.linalg.pinv(vect))

C:\Python27\lib\site-packages\numpy\linalg\linalg.pyc in pinv(a, rcond)
   1544     _assertNonEmpty(a)
   1545     a = a.conjugate()
-> 1546     u, s, vt = svd(a, 0)
   1547     m = u.shape[0]
   1548     n = vt.shape[1]

C:\Python27\lib\site-packages\numpy\linalg\linalg.pyc in svd(a, full_matrices, compute_uv)
   1269     """
   1270     a, wrap = _makearray(a)
-> 1271     _assertRank2(a)
   1272     _assertNonEmpty(a)
   1273     m, n = a.shape

C:\Python27\lib\site-packages\numpy\linalg\linalg.pyc in _assertRank2(*arrays)
    153         if len(a.shape) != 2:
    154             raise LinAlgError, '%d-dimensional array given. Array must be \
--> 155             two-dimensional' % len(a.shape)
    156 
    157 def _assertSquareness(*arrays):

LinAlgError: 1-dimensional array given. Array must be             two-dimensional

1 个答案:

答案 0 :(得分:4)

也许你想要这个?

>>> np.linalg.pinv([[1, 2, 3, 4]])
array([[ 0.03333333],
       [ 0.06666667],
       [ 0.1       ],
       [ 0.13333333]])

请注意额外的括号。正如错误消息所示,您只能采用矩阵的伪逆。如果你只有一个向量,你需要将它变成一个行矩阵。