#12029: Fast conversion of ClonableIntArray to list
-----------------------------+----------------------------------------------
Reporter: SimonKing | Owner: sage-combinat
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-4.8
Component: combinatorics | Keywords:
Work_issues: | Upstream: N/A
Reviewer: | Author: Simon King
Merged: | Dependencies:
-----------------------------+----------------------------------------------
Comment(by hivert):
Replying to [comment:2 SimonKing]:
> > - Since the new Cython allows it. Did you try to define an iterator
(using yield) without relying on the list ? It could be faster.
>
> As I stated in the ticket description: I did try, and it was not faster.
To be concrete: Here is the code that I tested.
Sorry I read it to fast !!!
> > - Also I'm not sure using append to build the list is a good idea (due
to possible reallocation).
>
> Appending to a list - if the list is cdefined - is a very quick
operation in Cython.
>
> > Si you know the list length from the beginning, why not allocation the
list and filling it with a loop ?
>
> Can one allocate a Python list without filling it?
From the C-API you can do it. Of course you must fill it (at least with
None(s)) before returning it to python. See
http://docs.python.org/c-api/list.html and in particular the note after
{{{PyList_New}}}. I don't know if it is doable directly in Cython without
calling the C-API.
Florent
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12029#comment:3>
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.
