#19545: Mathon's pseudocylic strongly regular graphs.
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Reporter: | Owner:
dimpase | Status: needs_info
Type: | Milestone: sage-6.10
enhancement | Resolution:
Priority: major | Merged in:
Component: graph | Reviewers:
theory | Work issues:
Keywords: | Commit:
Authors: Dima | 7da82db694e3b8c0467526ee5cc7141d40604dd6
Pasechnik | Stopgaps:
Report Upstream: N/A |
Branch: |
u/dimpase/matpc |
Dependencies: |
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Comment (by dimpase):
Replying to [comment:17 ncohen]:
thanks!
> Thank you for this strongly regular graph. Here is a first-pass review:
>
> - The `G` parameter scared me a bit, but it seems that you don't use it
at
> all. Same for `L`. Could you remove them?
well, I plan to provide an example of how to use L (for `v=441` (t=2) one
can get an interesting example). The smallest example where one can
provide G different from the default has `v=25*23^2` (t=4). I can do this
too (although it would be tagged `# very long time an' lotsa RAM`).
>
> - That's one useless lambda function `:-P`
> {{{
> #!diff
> -return (lambda q : MathonPseudocyclicStronglyRegularGraph(q),t)
> +return (MathonPseudocyclicStronglyRegularGraph,t)
> }}}
>
there are more places like this there - this one was copied from
`is_paley`...
> - (not important) you split 'import' blocks when they are longer than 80
> characters. I believe that in those cases the code is more readable if
you
> leave it on it line.
unless it's a violation of something, I don't mind
> {{{
> + from sage.matrix.constructor import matrix, block_matrix, \
> + ones_matrix, identity_matrix
> }}}
> If it were me I wouldn't have split this one. Just a remark, it's up
to you.
>
> - I don't think that you need to import `ValueError` (or any of the
common
> Python exceptions). It's always around.
>
> - Misleading index:
> {{{
> + # Order the elements of K in K_list
> + # so that K_list[i] = -K_list[n-i-1], and 0 comes last
> }}}
> `n-i-2`?
oh right, it's from your comments to something a bit different -- I'll fix
this.
>
> - You really don't find the latter more legible?...
> {{{
> P = map(lambda b: matrix(ZZ,q,q,lambda i,j: 1 if a[j]==a[i]+b else 0),
a)
> P = [matrix(ZZ,q,q,lambda i,j: 1 if a[j]==a[i]+b else 0)
> for b in a]
> }}}
`\begin{rant}`
I lived under various dictators, some more benevolent, some less. Often
one has to speak Aesop's (Esope, Ezop) language in order not to get in
trouble. Please consider this Aesope's language code my hidden protest
against Python's BDFL. (for I hate index variables and loops, while he
seems to enjoy pushing them down my throat :-))
`\end{rant}`
>
> - There is a missing ')' in your TODO block.
>
> Nathann
--
Ticket URL: <http://trac.sagemath.org/ticket/19545#comment:18>
Sage <http://www.sagemath.org>
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