Re: [ublas] compressed row storage

From: Nico Galoppo (nico_at_[hidden])
Date: 2007-06-08 13:56:07

Thanks guys!

--nico

Riccardo Rossi wrote:
> inex1_data are the rows
> index2_data are the columns
> value_data are the values
> 
> to get the underlying C-style array just write
> index1_data.data()
> 
> On Fri, 2007-06-08 at 19:04 +0200, Georg Baum wrote:
>> Am Freitag 08 Juni 2007 18:48 schrieb Nico Galoppo:
>>> Hi,
>>>
>>> I'm currently looking into writing a routine to convert a ublas type
>>> sparse matrix into a typical (row-oriented) compressed row storage (CRS)
>>> format, more specifically into a three arrays (values, columns & rowptr).
>>> Before I do so, I wanted to check with the list if this data is perhaps
>>> immediately available from the underlying storage in either
>>> compressed_matrix<> or coordinate_matrix<>? (their difference is unclear
>>> to me from the documentation).
>> compressed_matrix<> uses exactly that format (if instantiated with the 
>> correct template arguments), and it also has accessors for the arrays: 
>> index1_data(), index2_data() and value_data(). Don't ask me which is which 
>> (apart from value_data), the names are confusing.
>>
>> Coordinate matrix is different, it has a value array and two index arrays, 
>> all of the same size, where the row and column indices of each value are 
>> stored at the same position in the index arrays.
>>
>>
>> Georg
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-- 
Nico Galoppo        UNC-CH PhD. student        http://www.ngaloppo.org
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