[SciPy-dev] sparse deletion and sparse random matrices.
Viral Shah
vshah@interactivesupercomputing....
Sat Apr 19 12:31:52 CDT 2008
>> The two things I believe could be immediately useful are some simple
>> routines for deleting rows and columns, and routines to create sparse
>> random matrices. The latter would be greatly useful for examples,
>> exploration, debugging etc.
>>
>> The routines might look something like below. If there's interest, I
>> can help with whatever needs to be done to put them in the tree:
>
> sprand() would be useful however deleterowcol() is too special
> purpose IMO.
I meant that something like deleterowcol() could be used to implement
the delete() routines for sparse matrices. Currently, you can't delete
rows/cols from sparse matrices. I believe it is basic functionality
that would be nice to have, even if early implementations were not the
best.
> Two comments on your sprand()
> 1) leads to values outside [0,1) when an (i,j) entry occured more
> than once.
You are right. I did find that bug earlier this week, and fixed it.
> 2) fix(rand()) may be better implemented with
> numpy.random.random_integers()
Still familiarizing myself with all the stuff thats in numpy. That
would definitely be a better function to use.
> With a docstring + unittests this would make a nice addition to
> sparse/construct.py
Ok, I will dig into the source and figure out what all needs to be
done to put this in.
Thanks,
-viral
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