#16802: difference family database
-------------------------------------+-------------------------------------
Reporter: vdelecroix | Owner:
Type: enhancement | Status: needs_review
Priority: major | Milestone:
Component: combinatorial | Resolution:
designs | Merged in:
Keywords: | Reviewers:
Authors: Vincent Delecroix | Work issues:
Report Upstream: N/A | Commit:
Branch: public/16802 | c415a985d00e59bd0a60378e22f8f20f9df8accc
Dependencies: #16757 | Stopgaps:
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Comment (by ncohen):
Helloooooooooooo !!!
Very good code, efficient and all. I added a commit but I still have a
couple of remarks :
- What does that mean ?
{{{
+An example with a short block (i.e. considering restricted difference
when a
+block has a non trivial stabilizer)::
}}}
- I do not find the two messages about the checks over l very clear for a
user:
{{{
sum(1/s_i) k*(k-1) = {} is not a multiple of (v-1) = {} (stabilizer
sizes {})
}}}
The si are not defined (and it is hard to define them in an error
message)... What would you think of formulating that with BIBD
terminology ? A
bit like my comment about nb_diff in the code ?
- What do we do about non-commutative groups ? If we don't handle them it
would
be nice to have an error message sayng "the group is not commutative".
And if
we handle them we have to be more verbose about left/right actions and
everything (I personally think that it is going too far, but well)..
I did several things in my commit:
- move a DF that was not properly ordered
- expand the doc a bit in some places
- Removed the "abelian/additive" in `is_difference_family`, but that's
also part
of the more general question above.
- rename `c_counter` to `tmp_counter`
- Replace the `ValueError` in `difference_family` with an
`AssertionError`.
Tell me if you agree with those changes, and what you think of my
questions above. Before we set this ticket to `positive_review` I will
rebase it somehow, so that all design patches are linearly ordered.
Thanks !
Nathann
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Ticket URL: <http://trac.sagemath.org/ticket/16802#comment:9>
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