thank you for your quick reply.
Just for sake of documentation:
the output reads as [[[eigenvalue1, eigenvalue2],[multiplicity of
EVal1, multiplicity of EVal2]], Eigenvect of EVal1,..., Eigenvect
EVal1, Eigenvect of EVal2,..., Eigenvect of EVal2]
On 4 Mrz., 12:44, Jason Grout <jason-s...@creativetrax.com> wrote:
> sonium wrote:
> > Hi, I have problems calculating the eigenvectors of a symbolic matrix.
> > I tried:
>
> > a,b = var('a'),var('b')
> > M = matrix(SR,4,4,((a, 0, 0, 0), (0,-a,0,0), (0,0,a,0), (0,0,0,-a)))
> > M.eigenvectors_right()
>
> > what results in:
> > AttributeError: 'SymbolicArithmetic' object has no attribute 'degree'
>
> This comes from us not having a special implementation of the eigen
> functions for symbolic matrices (i.e., using maxima). For now, you can do:
>
> sage: a,b = var('a'),var('b')
> sage: M = matrix(SR,4,4,((a, 0, 0, 0), (0,-a,0,0), (0,0,a,0), (0,0,0,-a)))
> sage: M._maxima_().eigenvectors().sage()
> [[[-a, a], [2, 2]], [0, 1, 0, 0], [0, 0, 0, 1], [1, 0, 0, 0], [0, 0, 1, 0]]
>
> Seehttp://maxima.sourceforge.net/docs/manual/en/maxima_25.html#Item_003a...
> to understand the output of the command.
>
> The specific error you received came from there not being a .degree()
> method for a symbolic polynomial.
>
>
>
> > and
>
> > P.<a,b> = PolynomialRing(QQ)
> > M = matrix(P,4,4,((a, 0, 0, 0), (0,-a,0,0), (0,0,a,0), (0,0,0,-a)))
> > M.eigenvectros_right()
>
> > what gives:
>
> > Traceback (most recent call last):
> > File "<stdin>", line 1, in <module>
> > File "/home/sage/sagenb/sage_notebook/worksheets/sonium/1/code/
> > 26.py", line 6, in <module>
> > M.eigenvectors_right()
> > File "/home/sage/sage_install/sage-a/local/lib/python2.5/site-
> > packages/SQLAlchemy-0.4.6-py2.5.egg/", line 1, in <module>
>
> > File "matrix2.pyx", line 3054, in
> > sage.matrix.matrix2.Matrix.eigenvectors_right (sage/matrix/matrix2.c:
> > 18020)
> > File "matrix2.pyx", line 3000, in
> > sage.matrix.matrix2.Matrix.eigenvectors_left (sage/matrix/matrix2.c:
> > 17523)
> > File "matrix2.pyx", line 2755, in
> > sage.matrix.matrix2.Matrix.eigenspaces_left (sage/matrix/matrix2.c:
> > 16250)
> > File "matrix2.pyx", line 1058, in sage.matrix.matrix2.Matrix.fcp
> > (sage/matrix/matrix2.c:7456)
> > File "polynomial_element.pyx", line 2288, in
> > sage.rings.polynomial.polynomial_element.Polynomial.factor (sage/rings/
> > polynomial/polynomial_element.c:18681)
> > NotImplementedError
>
> I'm not sure what is going on here...
>
> Thanks,
>
> Jason
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to sage-support@googlegroups.com
To unsubscribe from this group, send email to
sage-support-unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/sage-support
URLs: http://www.sagemath.org
-~----------~----~----~----~------~----~------~--~---
