Re: [ublas] Difference between the different sparse matrix types?

From: Markus Weimer (markus.weimer_at_[hidden])
Date: 2008-01-23 07:13:56

Hi,

many thanks!

Markus

On 23.01.2008, at 09:01, Gunter Winkler wrote:

> Am Dienstag, 22. Januar 2008 02:40 schrieb Markus Weimer:
>> Hi,
>> what are the differences between the different sparse matrix types
>> (Mapped Matrix, Compressed Matrix and Coordinate Matrix)? The
>> descriptions on the site
>> <http://www.boost.org/libs/numeric/ublas/doc/matrix_sparse.htm> all
>> read alike and I am kind of puzzled...
>
> The different kinds serve differet goals:
>
> mapped_matrix: use a simple hash map and thus rely on the  
> performance of
> the STL.
>
> compressed_matrix: fast element lookup, superior axpy speed, low  
> memory
> usage, but slow structure changes (insert, erase)
>
> coordinate_matrix: fast addition (append_element), good axpy speed,  
> but
> slow element look up, possibly large memory usage
>
> generalized_vector_of_vector (e.g. vector<compressed_vector<..> >):
> fast row look up, fast/moderate element lookup, moderate structure
> changes, moderate axpy speed.
>
> Personally I use the gvov for assembling and compressed_matrix for
> further computations. Most of the time the necessary copy operation is
> more than compensated.
>
> cf. http://www.guwi17.de/ublas/matrix_sparse_usage.html
>
> mfg
> Gunter
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