#9108: Mark long doctests in rings/polynomial/symmetric_ideal
-----------------------------------+----------------------------------------
Reporter: leif | Owner: malb
Type: defect | Status: positive_review
Priority: minor | Milestone: sage-4.4.3
Component: commutative algebra | Keywords: time-out, doctest, symmetric
ideal, symmetric_ideal
Author: | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
-----------------------------------+----------------------------------------
Comment(by SimonKing):
Replying to [comment:5 cremona]:
> Interesting to note that it is essentially just one test which takes the
time!
Off list, Leif just sent me some timings:
There is one symmetric Groebner basis computation that takes 73 seconds,
but most of the time is actually spent for testing whether all variable
permutations of all basis elements do indeed have symmetric reduction zero
modulo the symmetric Groebner basis: 130 s.
I see two ways to proceed, depending on how soon the next release is due:
1. Leif's patch could go in, as John gave it a positive review, and it is
certainly harmless and solves the problem.
2. I could try to find a solution for the one offending doc test. For
example, the long Groebner basis computation could be replaced by
something else, such us the following, of course without the timings that
I just inserted for demonstration:
{{{
sage: R.<x,y> = InfinitePolynomialRing(GF(5),order='degrevlex')
sage: I = [2*x[4]*x[3]*y[4] - 2*y[0]^3]*R
sage: %time G = I.groebner_basis()
CPU times: user 1.70 s, sys: 0.01 s, total: 1.71 s
Wall time: 1.71 s
sage: G
[x_2*x_1*y_1 - y_0^3, x_2*x_1*y_2 - y_0^3, y_2*y_0^3 - y_1*y_0^3]
sage: %time [[(p^P).reduce(G) for p in G] for P in
Permutations(Integer(3))]
CPU times: user 1.38 s, sys: 0.00 s, total: 1.38 s
Wall time: 1.38 s
[[0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0]]
}}}
I think this example would actually be a good one, as it shows:
* Even a "principal" symmetric ideal may have a reduced symmetric
Groebner basis formed by more than one element.
* The test whether the elements still reduce to zero after variable
permutation is easier, since the maximal variable index can be smaller (3
instead of 4; it should be bigger than the maximal index 2 that occurs in
the symmetric Groebner basis).
So, if the next release will be soon, I suggest to take Leif's patch as it
is. But I think in the long run, a new example (like the one above) is
needed.
Concerning line lengths: Does this only concern the first line of the doc
strings? I know that my first lines tend to be rather lengthy, as I learnt
that the basic description of the functionality should be given in the
first line of the doc string (this is why I don't do a line wrap).
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/9108#comment:6>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" 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/sage-trac?hl=en.
