Re: [eigen] StdVector

[Gael Guennebaud <gael.guennebaud@xxxxxxxxx>]

UPDATE

rev 957053 should also fix the linkage issue. At least with my trivial
example it now works. So please, Markus (and others), can you tell us
if that work for you ?

The current solution still only require the inclusion of
Eigen/StdVector without any other change.

cheers,
Gael.



On Tue, Apr 21, 2009 at 12:54 PM, Gael Guennebaud
<gael.guennebaud@xxxxxxxxx> wrote:
> On Tue, Apr 21, 2009 at 12:27 PM, Alex Stapleton
> <alex.stapleton@xxxxxxxxxxxxx> wrote:
>> My mail server had a few bad days so I haven't been in on all of this thread
>> but I've read through the archive.
>> Beinoit Jacob Wed, 15 Apr 2009 14:30:24 +0200
>>>
>>> If not, there was the previous solution by Alex and myself. But it had the
>>> problem of not being extensible to user types. Maybe that's worth a second
>>> round of thinking? I don't remember exactly what prevented making macros
>>> allowing the user to extend it to custom types.
>>
>> What prevented adapting the old system into an easier to use library that
>> users could easily use to give their own types alignment safety in
>> std::vector? It's been a while since I worked on that code so I can only
>> vaguely remember how I got it to work :( (Yes this does count as me
>> volunteering to try and make it nice and easy for people to use if that's an
>> acceptable solution.)
>> Alex Stapleton
>
> The main problem was you needed to duplicated all the constructors.
>
> The main problem of the solution I proposed was I had to add an extra
> template parameter to std::vector<> so that I can specialize
> std::vector for types having a given member. This tricks yield to
> linking error when linking to code compiled with the original
> std::vector. Now, if someone is smart enough to find a solution to
> specialize std::vector for any types having a given member without
> adding a new template parameter, then this would be awesome !
>
> In case there is no miracle, I'll apply the patch from Hauke, where
> the solution is to enforce users to explicitly use the
> Eigen::aligned_alocator. Based on that solution, we could also easily
> provide macros so that the user can instantiate the specialization
> once for all. For non template class this would be very easy, and we
> just need the name of the class. For a template class, we also need to
> pass to the macro the types and names of the template parameters,
> e.g.:
>
> EIGEN_DEFINE_STL_VECTOR_SPECIALIZATION_TPL_<N>(ClassName,
> Type1,Name1,Type2,Name2,Type3,Name3,...));
>
>  If we don't want to define one macro per number of template
> arguments, we have to use some advanced meta-preprocessor tricks. For
> instance the API could be:
>
> EIGEN_DEFINE_STL_VECTOR_SPECIALIZATION_TPL(ClassName, NbTplParams,
> (Type1,Name1,Type2,Name2,Type3,Name3,...)));
>
> Question1: is it worth the effort ? (macro's names and API might be changed !)
>
> if yes, then Question2: is anyone interested in writing such macros ?
>
> cheers,
>
> Gael
>
>
>>
>> 2009/4/21 Hauke Heibel <hauke.heibel@xxxxxxxxxxxxxx>
>>>
>>> Hi again,
>>>
>>> I have a patch proposal attached. It is build based on this mornings
>>> SVN repository.
>>>
>>> Cheers,
>>> Hauke
>>
>>
>