Re: [ublas] Matrix multiplication performance

Subject: Re: [ublas] Matrix multiplication performance
From: Nasos Iliopoulos (nasos_i_at_[hidden])
Date: 2016-01-29 10:01:48

One can use this:
https://github.com/uBLAS/ublas/blob/master/include/boost/numeric/ublas/experimental/sparse_view.hpp

generally I think the container view (matrix_view, vectror_view, etc) 
classes are important and should be put together sooner than later. An 
approach would be to follow Example 3 - a read only adapter in:
http://www.guwi17.de/ublas/examples/
but disable some the illegal code (like resizing)

-N

On 01/28/2016 05:02 PM, Riccardo Rossi wrote:
>
> Well there is pastix...which is c99 and performs way better than superlu.
>
> Now seriously I think ublas misses a sparse spmm algorithm.
>
> The fastest implementation I am aware of is in viennacl. (C++)
>
> The limitation for writing a good one in ublas is mostly that it 
> misses a constructor in which csr arrays are passed already built 
> (ideally via move semantics I guess).
>
> If you redesign ublas think about how to provide such access!
>
> Cheers
> Riccardo
>
> On 28 Jan 2016 22:01, "Karl Meerbergen" 
> <karl.meerbergen_at_[hidden] 
> <mailto:karl.meerbergen_at_[hidden]>> wrote:
>
>
>     > On 28 Jan 2016, at 21:47, Michael Lehn <michael.lehn_at_[hidden]
>     <mailto:michael.lehn_at_[hidden]>> wrote:
>     >
>     >
>     >
>     >> do you also do sparse linear algebra by chance?
>     >
>     > Sorry, not directly.  I just looked at libraries like SuperLU
>     and Umfpack.  However, not as close as to other BLAS libraries.  But
>     > from my impression this also could be done much more elegant in
>     C++.  The big headache in these libraries is that they basically
>     > have the same code for float, double, complex<float> and
>     complex<double> .  Just using C++ as "C plus function templates” would
>     > make it much easier.  And the performance relevant part in these
>     libraries is again a fast dense BLAS.
>
>     Correct, but I would bet on MUMPS, which is,in my opinion, more
>     advanced and still improving. They also use a ’template’ mechanism
>     in fortran 90, based on the C preprocessor ;-) They made it clear
>     they will not redo their developments of more than 30 man years in
>     C++.
>
>     Best,
>
>     Karl
>
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