#15431: Transversal Design TD(6,12)
-------------------------+-------------------------------------------------
Reporter: | Owner:
ncohen | Status: needs_review
Type: | Milestone: sage-6.2
enhancement | Resolution:
Priority: major | Merged in:
Component: | Reviewers:
combinatorics | Work issues:
Keywords: | Commit:
Authors: | 4adf6b5792919daea356c66d511fc621776d0a77
Nathann Cohen | Stopgaps:
Report Upstream: N/A |
Branch: |
u/ncohen/15431 |
Dependencies: |
#15287 #15368 |
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Comment (by vdelecroix):
Replying to [comment:11 ncohen]:
> Hellooooo !
>
> > I am very happy with the `EmptySetError`. Could you raise it *before*
the check t=2 ?
>
> I believe it is already the case in the branch.
Nope. Look line 200 and 203.
> > OA and TD are the same objects up to relabeling.
>
> Yep !
>
> > More precisely, an OA is a TD with sets V1 = V2 = ... = Vn = [n]
whereas you choose the convention V1 = [n], V2 = [n,2n], ... for the TD. I
do not see the point of having two different functions... please tell me.
I was not arguing about MOLS which for me looks really different. TD and
OA are the very same up to a stupid relabeling. Please do not argue about
MOLS, I want to leave them for now.
> Why a TD and a OA ? Well, because the books talk of both. Sometimes the
same book talks of the two things, and sometimes you do not want to do
this relabeling by yourself. They are the same objects (as well as MOLS)
and so the code must not repeat itself, but the two objects exist in the
book and so I think the two objects should exist here too.
This is an argument for having two entry points but not having two places
where to find the code.
> As any construction of a MOLS or OA or TD can be translated into a
construction of another of the three, it is technically possible to have
only one main function, and two "translating" functions when needed. But
those constructions I found in books are already quite unclear, there is
already a lot of relabelling being done "silently" in the constructions,
and I thought it could only help to write the constructions in their
original formalism instead of translating them. Plus it would really be a
pain to translate all the proofs while reading them, what I wrote was not
thaaaaat easy to translate into code already `:-P`
I believe this was not easy, but my job is review. And it should be clear
for anybody who reads the code why there are two different functions TD
and OA. With the definition you gave in the documentation a OA *is* a TD.
On the other hand, look at the code of transversal_design... it is almost
empty except `TD6_12` which is the reason of this patch. I do not see any
reason for having different functions at this point. Do you think
`transversal_design` will get bigger ?
--
Ticket URL: <http://trac.sagemath.org/ticket/15431#comment:13>
Sage <http://www.sagemath.org>
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