Today I came across the following problem. I start by computing the Gutman
energy for a graph:
sage:
c26 = Graph('YsP@H?PC?O`?@@?_?G?@??CC?G??GG?E??@_??K???W???W???H???E_')
sage:
ge = sum(lam for lam in c26.adjacency_matrix().eigenvalues() if lam > 0)
sage: ge
19.87092248988078?
So far everything seems to be OK, but then I try
sage: float(ge)
Now you can wait for a very long time. (I actually didn't test to see how
long it would exactly take) The type of ge is
sage.rings.qqbar.AlgebraicNumber. Looking at the implementation of the
float conversion, the problem seems to come from the following:
sage: AA(ge)
This indeed also seems to take forever. At that point I'm lost. I don't
really understand much of that part of Sage, so I don't know how to look
further for a solution to this problem. Is there another way to get a good
float approximation of that value?
Cheers
Nico
--
You received this message because you are subscribed to the Google Groups
"sage-support" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sage-support.
For more options, visit https://groups.google.com/d/optout.
