Comment #2 on issue 2231 by [email protected]: Matrix determinant
properties are not satisfied.
http://code.google.com/p/sympy/issues/detail?id=2231
What version of SymPy do you use? In master branch of our development
repository your example gives:
In [1]: var('a,b,c,d')
Out[1]: (a, b, c, d)
In [2]: B=Matrix([a,b],[c,d])
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
/home/mateusz/repo/git/sympy/<ipython console> in <module>()
/home/mateusz/repo/git/sympy/sympy/matrices/matrices.pyc in __init__(self,
*args)
154 self.mat = []
155 else:
--> 156 raise TypeError("Data type not understood")
157
158 def key2ij(self,key):
TypeError: Data type not understood
Also don't compare expressions like this
Matrix.det(B)*Matrix.det(B) == Matrix.det(B*B)
because `==` is structural comparison operator, e.g.
In [5]: a*(a + b) == a**2 + a*b
Out[5]: False
Correct would be to write:
In [6]: (B**2).det() == expand(B.det()**2)
Out[6]: True
Compare this with:
In [7]: (B**2).det() == B.det()**2
Out[7]: False
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