Hi!
On Sat, Jan 01, 2011 at 05:31:13PM -0500, Sébastien Labbé wrote:
> > De Bruijn sequences are finite words. It would seem logical to include
> > De Bruijn sequences as finite words, since they do fit the definition.
>
> Amongst the method of the class WordGenerator, most return infinite
> words but some return finite words (like PalindromicDefectWord,
> RandomWord and fibonacci_tile).
>
> So if it is a finite word, then it could be represented as a python
> list, tuple, str, a function {0,1,2...n} -> or a finite iterator.
Thanks Sébastien for the feedback!
> > What is the reason for not including necklaces and Lyndon Words there,
> > for example? Are they not also words?
They point is that, for necklaces, Lyndon words, dyck words, and the
like, the main mathematical object is not a word, but a set of
words. And the main operations are to count them, to iterate through
them, etc. So everything revolves around the corresponding enumerated
sets of words: Necklaces([2,1,1]), DyckWords(n), ...
Granted, there is still some merging and cleanup to do. For example,
the elements of DyckWords(n) could possibly be returned as words, etc.
Comming back to DeBruijn sequences, I see two options:
- Either we clearly foresee that people will eventually be interested
in operations like counting or iterating through all DeBruijn
sequences for a given alphabet/n. And then the entry point for the
user shall be:
sage: DeBruijnSequences(alphabet, n)
The set all de Bruijn sequences over ...
with a 's', even if for the moment an_element is the only
implemented feature:
sage: DeBruijnSequences(alphabet, n).an_element()
[ .... ]
- Or all we really care about is to construct one De Bruijn sequence
for that alphabet and n, and then it should be:
sage: words.DeBruijnSequence(alphabet,n)
[ ... ]
An independent question is to decide whether the result shall be a
tuple, a word, or ... It is perfectly fine to leave this not specified
to leave our hands free for the future; e.g. just say that the result
is an iterable l which also supports random access (i.e. l[i]), and
possibly len(l).
I let you choose whatever feels more appropriate!
Cheers,
Nicolas
--
Nicolas M. Thiéry "Isil" <nthi...@users.sf.net>
http://Nicolas.Thiery.name/
--
You received this message because you are subscribed to the Google Groups
"sage-combinat-devel" group.
To post to this group, send email to sage-combinat-de...@googlegroups.com.
To unsubscribe from this group, send email to
sage-combinat-devel+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/sage-combinat-devel?hl=en.
