Hi,

I can understand Dimitri's frustration, it seems the optimization framework 
gets worse with every iteration. However, we should probably look forward and 
think about how to design it properly instead. 

Several times I brought out some problems and ideas about the package and it 
seems the only person who has an opinion is Gilles.

I will list what I consider to be major problems
1) The OO design is bad, too much inheritance which could be handled better by 
interfaces, the structure has no relation to the actual way parts of optimizers 
can be mixed and matched. Input functions should also have clear inheritance 
structure and should return both the value, gradient, hessian in one function 
call.
2) Incorrect handling of constraints. There are only something like 5 possible 
constraints possible in optimization, with each implementation of the solver 
handling some but not all. There is no need to this runtime approach, which 
creates incredible amount of confusion. All the possible constraints should be 
explicitly given in the parameters to a function call, there are only 5. In 
addition, constraints should be pre-processed a priori! So they should be an 
input to the constructor not to the optimization function call.
3) Linear algebra package should be used as an interface and internally to 
increase performance for larger datasets. Data copying should be avoided as 
much as possible.
4) Testing should be done on larger problems.

I know the response is that I am free to go implemented, but I think we should 
at least agree on design principles instead of pushing through your own ideas 
because the other person is too busy. The only discussion we ever had on this 
was between me and Gilles, everyone else disappeared. 

Thanks,
Konstantin

On Dec 28, 2012, at 11:27 AM, Phil Steitz <phil.ste...@gmail.com> wrote:

> On 12/28/12 8:12 AM, Dimitri Pourbaix wrote:
>> Luc,
>> 
>>> So in order to make sure I understand your point, you would be OK
>>> if I
>>> deprecate the non-diagonal weights, in which case users needing this
>>> would have to implement it themselves by premultiplication (as
>>> both you
>>> and Konstantin seem to propose)?
>> 
>> Yes, exactly.
>> 
>>> Sure, but for the record the feature was also a last minute
>>> change. This
>>> was discussed on the list, and the final decision was to add this
>>> feature despite the release was close. No wonder we failed to
>>> test it
>>> thoroughsly.
>> 
>> Last minute?  I have been discussing this with Gilles for several
>> months.
> 
> Relevant project discussion happens *on this list*
>> 
>>> We don't expect our releases to be perfect. We do our best, with the
>>> resources we have.
>> 
>> I perfectly understand this but focusing those resources less on
>> rules
>> and more on real cases might help.
> 
> As stated before, you are more than welcome to *become* one of these
> resources.
> 
> Phil
>> 
>> Regards,
>> Dim.
>> ----------------------------------------------------------------------------
>> 
>> Dimitri Pourbaix                         *      Don't worry, be happy
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