[SciPy-dev] Matrix Structure Plots in scipy ?

Nils Wagner nwagner at mecha.uni-stuttgart.de
Wed Oct 6 07:06:00 CDT 2004


Pearu Peterson wrote:

>
>
> On Wed, 6 Oct 2004, Nils Wagner wrote:
>
>> The number of outputs is more than described in help (io.mmio)
>>
>>
>>   mmread(source)
>>       Reads the contents of the Matrix Market file 'filename' into 
>> the matrix 'A'.
>>
>>       Inputs:
>>
>>         source    - Matrix Market filename (extension .mtx) or open 
>> file object.
>>
>>       Outputs:
>>
>>         a         - sparse or full matrix
>>
>> Actually
>>
>> b,m,n,s = mmread('young1c')
>>
>> should be used.
>
>
> Since the values for m,n,s are available via mminfo then I have 
> changed the signature of mmread to
>
>   a = mmread(source)
>
> Btw, one can now also write sparse matrices using mmwrite.

Is it also possible, that mmread returns sparse matrices when reading
sparse matrices from *.mtx ?

Is it generally possible to switch between sparse and dense format of 
matrices
in scipy ?

Now, scipy has some iterative solvers for linear systems. Can I use both
dense and sparse matrices with respect to cg,... ?

How about sparse eigensolvers in scipy e.g. ARPACK ?

Nils


> Pearu
>
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