Dear List, I just discovered the following (imho unsatisfactory) behavior of Matrix.det:
In <211>: from sympy.abc import a,b,c,d, C In <212>: M = Matrix([[a+b, 0, cos(c)], [0, d, 0], [cos(c), 0, 1]]) In <213>: M Out<213>: [ a + b, 0, cos(c)] [ 0, d, 0] [cos(c), 0, 1] In <214>: M.det() Out<214>: d*a**2/(a + b) + d*b**2/(a + b) + 2*a*b*d/(a + b) - a*d*cos(c)**2/(a + b) - b*d*cos(c)**2/(a + b) I wonder why there are fractions in the result (all the more as in the docstring of det_bareis one reads, that the algorihtm "will result in a determinant with minimal number of fractions".). The result is correct but it is in a very inconvenient form for further processing. My observation is, that the result of det is better (i.e. as expected) if there are no trigonometric terms in the matrix: In <215>: M.subs(cos(c), C).det() Out<215>: a*d + b*d - d*C**2 Is that a bug or do I miss something? Regards, Bastian. -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
