PythonでTraceを計算してみる ref: http://qiita.com/kyoro1/items/77b1b7c9634e16f09ee4

file0.txt

{\rm Tr}(PAP^{-1})={\rm Tr}(A)

file1.txt

{\rm Tr}(A):=\sum_{i=1}^na_{ii} 

file2.txt

A=\left(
\begin{matrix}
1 & 2 \\
3 & 4 
\end{matrix}
\right),
P=\left(
\begin{matrix}
2 & 3 \\
4 & 5 
\end{matrix}
\right)

file3.py

> import numpy as np
> A = np.array([[1,2],[3,4]])
> P = np.array([[2,3],[4,5]])

file4.py

> A 
array([[1, 2],
       [3, 4]])
> P
array([[2, 3],
       [4, 5]])

file5.py

> np.linalg.det(P)
-2.0

file6.py

> np.trace(np.dot(np.dot(P,A),inv_P))
5.0
> np.trace(A)
5