Re: [eigen] SVD with singular matrices

[Thomas Capricelli <orzel@xxxxxxxxxxxxxxx>]

I highly prefer 1 over 2. Anyway we can't have 'svd' and 'jacobisvd', so at least the current svd should have a better name, mentionning the algo, and not a quality (FastSVD -> no), to be coherent with other names. Then... if it's that much buggy, just remove it.

(2) is ugly, because it's about using two names for the same algo, and change the underlying algo underneath.. and even keeping a inconsistent naming for the "SVD". Really bad, imho.

I can do with keeping it and renaming it for consistency, but if this bug is so important for others, we need to either fix or remove. And.. yes, ... i know, when i say "we", I of course mean Benoit, sorry i can't fix that myself.

Also, as i already use the current SVD in some projet, i'd like a confirmation that the jacobisvd is "only" two (or 3, or constant) times slower. That is that they share the same complexity (as in O() notation) with respect to the size of matrices.

regards,

--

Thomas Capricelli <orzel@xxxxxxxxxxxxxxx>

http://www.freehackers.org/thomas

On Thursday 30 September 2010 13:26:46 Benoit Jacob wrote:

> So:

>  - 1) should we just plain remove SVD and tell people to use JacobiSVD

>  - 2) or should we, as said above, just internally reimplement SVD on

> top of JacobiSVD ?

>

> I'm getting more and more in favor of 1). Like in other modules, use

> explicit decomposition names. My concern is that with 2), in Eigen 3.1

> we'd silently replace SVD by a faster but NOT AS RELIABLE

> implementation. Dangerous!