|Re: [eigen] Student contribution|
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- To: eigen <eigen@xxxxxxxxxxxxxxxxxxx>
- Subject: Re: [eigen] Student contribution
- From: Benoit Jacob <jacob.benoit.1@xxxxxxxxx>
- Date: Sun, 16 Jun 2013 17:08:20 -0400
- Cc: simon.courtemanche@xxxxxxxx, Pierre ZOPPITELLI <Pierre.Zoppitelli@xxxxxxxxxxxxxxx>, Nicolas Carré <carren@xxxxxxxxxxxxxx>, Jean CECCATO <Jean.Ceccato@xxxxxxxxxxxxxxx>
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Maybe I shouldn't have hopped onto this thread: I have been away from the Eigen project for a long while, and it's up to the current maintainers, not me, to decide on the specifics here.
My personal opinion is that what we really want, as described in bug 67, is something similar to LAPACK's SGESDD. As Gael pointed out, this should bring an order-of-magnitude speed improvement over JacobiSVD, at least on already-bidiagonal matrices (the rest is up to the speed of bidiagonalization, which can we worked on independently).
A 1.7x speed improvement is always nice, but I will leave it up to current maintainers to decide where exactly the bar is for deciding to include a new SVD algorithm. Of course, as you suggested, there is always the option to include it in unsupported/ so that it can be easily found and improved by other people.
The other factor to consider to what extent this code provides the right basis for a future implementation of the SGESDD-like SVD.