<p>您链接到<a href="https://stackoverflow.com/questions/11953867/how-do-i-find-out-eigenvectors-corresponding-to-a-particular-eigenvalue-of-a-mat">How do I find out eigenvectors corresponding to a particular eigenvalue of a matrix?</a>并说它不计算左特征向量,但是您可以通过处理转置来修复它。在</p>
<p>例如</p>
<pre><code>In [901]: import numpy as np
In [902]: import scipy.sparse.linalg as sla
In [903]: M = np.array([[0.5, 0.25, 0.25, 0], [0, 0.1, 0.9, 0], [0.2, 0.7, 0, 0.1], [0.2, 0.3, 0, 0.5]])
In [904]: M
Out[904]:
array([[ 0.5 , 0.25, 0.25, 0. ],
[ 0. , 0.1 , 0.9 , 0. ],
[ 0.2 , 0.7 , 0. , 0.1 ],
[ 0.2 , 0.3 , 0. , 0.5 ]])
In [905]: eval, evec = sla.eigs(M.T, k=1, which='LM')
In [906]: eval
Out[906]: array([ 1.+0.j])
In [907]: evec
Out[907]:
array([[-0.32168797+0.j],
[-0.65529032+0.j],
[-0.67018328+0.j],
[-0.13403666+0.j]])
In [908]: np.dot(evec.T, M).T
Out[908]:
array([[-0.32168797+0.j],
[-0.65529032+0.j],
[-0.67018328+0.j],
[-0.13403666+0.j]])
</code></pre>
<p>要规范化特征向量(您知道应该是实数):</p>
^{pr2}$
<p>如果您事先不知道特征值1的重数,请参阅@pv的注释,使用<code>scipy.linalg.eig</code>显示代码。下面是一个例子:</p>
<pre><code>In [984]: M
Out[984]:
array([[ 0.9 , 0.1 , 0. , 0. , 0. , 0. ],
[ 0.3 , 0.7 , 0. , 0. , 0. , 0. ],
[ 0. , 0. , 0.25, 0.75, 0. , 0. ],
[ 0. , 0. , 0.5 , 0.5 , 0. , 0. ],
[ 0. , 0. , 0. , 0. , 0. , 1. ],
[ 0. , 0. , 0. , 0. , 1. , 0. ]])
In [985]: import scipy.linalg as la
In [986]: evals, lvecs = la.eig(M, right=False, left=True)
In [987]: tol = 1e-15
In [988]: mask = abs(evals - 1) < tol
In [989]: evals = evals[mask]
In [990]: evals
Out[990]: array([ 1.+0.j, 1.+0.j, 1.+0.j])
In [991]: lvecs = lvecs[:, mask]
In [992]: lvecs
Out[992]:
array([[ 0.9486833 , 0. , 0. ],
[ 0.31622777, 0. , 0. ],
[ 0. , -0.5547002 , 0. ],
[ 0. , -0.83205029, 0. ],
[ 0. , 0. , 0.70710678],
[ 0. , 0. , 0.70710678]])
In [993]: u = lvecs/lvecs.sum(axis=0, keepdims=True)
In [994]: u
Out[994]:
array([[ 0.75, -0. , 0. ],
[ 0.25, -0. , 0. ],
[ 0. , 0.4 , 0. ],
[ 0. , 0.6 , 0. ],
[ 0. , -0. , 0.5 ],
[ 0. , -0. , 0.5 ]])
In [995]: np.dot(u.T, M).T
Out[995]:
array([[ 0.75, 0. , 0. ],
[ 0.25, 0. , 0. ],
[ 0. , 0.4 , 0. ],
[ 0. , 0.6 , 0. ],
[ 0. , 0. , 0.5 ],
[ 0. , 0. , 0.5 ]])
</code></pre>