Hi!
I just wrote some code on the sage-combinat queue which computes a matrix with entries in a polynomial ring R = PolynomialRing(QQ, 'x', n)
{{{ sage: P = Poset(([1,2,3,4], [[1,3],[1,4],[2,3]]), linear_extension = True) sage: L = P.linear_extensions() sage: M = L.markov_chain_transition_matrix(labeling = 'source') sage: M [-x0 - x1 - x2 x3 x0 + x3 0 0] [ x1 + x2 -x0 - x1 - x3 0 x1 0] [ 0 x1 -x0 - x3 0 x1] [ 0 x0 0 -x0 - x1 - x2 x0 + x3] [ x0 0 0 x0 + x2 -x0 - x1 - x3]
sage: M.eigenvalues()
NotImplementedError Traceback (most recent call last)
/Applications/sage-5.0.beta7/devel/sage-combinat/sage/combinat/posets/<ipython console=""> in <module>()
/Applications/sage-5.0.beta7/local/lib/python2.7/site-packages/sage/matrix/matrix2.so in sage.matrix.matrix2.Matrix.eigenvalues (sage/matrix/matrix2.c:26415)()
/Applications/sage-5.0.beta7/local/lib/python2.7/site-packages/sage/matrix/matrix2.so in sage.matrix.matrix2.Matrix.fcp (sage/matrix/matrix2.c:11089)()
/Applications/sage-5.0.beta7/local/lib/python2.7/site-packages/sage/rings/polynomial/polynomial_element.so in sage.rings.polynomial.polynomial_element.Polynomial.factor (sage/rings/polynomial/polynomial_element.c:22655)()
NotImplementedError: }}}
Is it possible to compute this some other way or is this just not yet implemented (which would surprise me!).
Thanks,
Anne