Re: [ublas] new fixed size matrix class

From: Hajime SAITO (emijah_s_at_[hidden])
Date: 2006-08-09 00:49:08

Thank you for your replies. Sorry for the late response.

We are working on a simulator that we plan to release as open source. I 
have looked at Tvmet and also MTL. I tried benchmarking with BTL which 
is something that was part of the OpenCascade project and found that 
indeed tvmet was faster. However I was thinking that if boost::ublas was 
the larger effort so perhaps we could contribute back to it and prevent 
all these open source projects from diverging and creating packages that 
are slightly different from each other. I was also looking at using the 
boost graph library and other components so I chose uBlas.

I think there are others who feel the same way about performance for 
small matrices. I am willing to try things out with the code we 
currently have to make comparisons.

I find the generation of specializations appealing if there are too many 
combinations to consider. However(like the questions Ricardo Rossi has 
posted) I have yet to find the location to which I can add the 
specializations.

Dave Steffen wrote:
> Gunter Winkler writes:
>  > John Maddock schrieb:
>  > > emijah_s_at_[hidden] wrote:
>  > >   
>  > >> Could you please elaborate on the last part? We are using uBlas for a
>  > >> robotics application and the typical size of a matrix tends to be
>  > >> pretty small(around 6x6 typical, 35x35 maximum). So it doesn't really
>  > >> make sense to use atlas which tends to be effective for large
>  > >> matrices.
>  > >>     
>  > >
>  > > I wonder have you looked at MTL ?  It's optimised for small matices and 
>  > > known to be very fast in this case: http://osl.iu.edu/research/mtl/
>  > >   
>  > this is only partially true. The performance of small MTL matrices was 
>  > quite bad until someone wrote short and lean specializations for small 
>  > matrix/vector products. I can give more details (and the files) if 
>  > someone is interested. The specializations for a given size were created 
>  > by a python script.
>
>  Tvmet is also worth a look, if you're looking around; explicitly
>  build for small problems ("tiny vector matrix expression template",
>  or some such) and it's extremely fast, according to my profiling.
>
> ----------------------------------------------------------------------
> Dave Steffen, Ph.D.      
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