[SciPy-user] sparse matrix formats

David Grant david at dwavesys.com
Tue Oct 26 17:29:54 CDT 2004


Travis Oliphant wrote:

> David Grant wrote:
>
>> I am a bit boggled by all these sparse matrix types in the sparse class.
>>
>> Can anyone recommend which are the standard one I should use (when in 
>> doubt)?
>
>
> spmatrix is just the base class and is not functional by itself:
>
> The formats at the top are currently best supported.
> csc_matrix  --- used internally by lot's of routines, best for 
> numerics but can be slow to construct using Python indexing
> csr_matrix  ---  nearly as fast as csc_matrix and useful for fast 
> transpose operations.
> dok_matrix --- fast construction in Python (just a simple dictionary), 
> but must be converted to csc_matrix for fast matrix multiplication, etc.

Thanks a lot!

>
> I hope this helps,
>
> The documentation is lacking for Sparse, but the code should be fairly 
> readable.  Just ignore all but csc_matrix, csr_matrix, and dok_matrix  
> for now.

Yeah, it looks like those are the only three with complete-ish code written.

>
> There are some bugs in dok_matrix  and in mixed csc csr matrix 
> multiplication in SciPy 0.3.2 that have been fixed in CVS.
>
>


-- 
David J. Grant
Scientific Officer
Intellectual Property
D-Wave Systems Inc.
tel: 604.732.6604
fax: 604.732.6614


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