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From Dimitri Pourbaix <pourb...@astro.ulb.ac.be>
Subject Re: [Math] Remove "BOBYQAOptimizer"
Date Wed, 02 Jan 2013 08:10:13 GMT
Hi Gilles,

> "BOBYQAOptimizer" is a horrible Java code (e.g. it contains lots of
> "simili-goto" statements).[2]
> In a library, the source codes should share coding standards. Consequently,
> if a code is not following the standard, it should not be part of the
> library. We simply should not have included it.
> It is not, and cannot be, maintained; it is just there. You could as well
> copy/paste it to your personal toolbox.

Although I understand your concern about the (un)maintainability of
"BOBYQAOptimizer" as a CM contributor/maintainer, I fully share Patrick's
point of view as a user!  Unless CM is a toy for the own pleasure of its
contributors, it should not make the life of its users miserable every time
some CM officionados have yet another great idea about how to 'improve'
the design/implementation of an algorithm already in place, especially if
the adopted design results essentially from a philosophical orientation.

Following the discussions on the dev ML, I see that some components which
were to be deprecated are now restored, ...  Such a rather unstable API
is really bad from a user point of view.  As Patrick wrote, we do not want
to waste hours or days catching up with the deprecations (especially as we
have to figure out the refactoring ourselves).  We do want to use CM as a
reliable library but if something works, do not touch it!

That is for instance the case with the weights in the least squares methods.
Those vectorial weights have been very useful in the present API, do not
touch them.  That API does not prevent a tiny subset of users to cope with
correlated observations while it helps a lot of users coping with simple
weights.  For the latter, there is even a good reason not to premultiply
the observations and model functions: the 'residuals' would be multiplied
as well otherwise.

Best wishes for 2013.
  Dim.
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Dimitri Pourbaix                         *      Don't worry, be happy
Institut d'Astronomie et d'Astrophysique *         and CARPE DIEM.
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http://sb9.astro.ulb.ac.be/~pourbaix     * mailto:pourbaix@astro.ulb.ac.be

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