Re: [eigen] StdVector

[Benoit Jacob <jacob.benoit.1@xxxxxxxxx>]

2009/4/15 Robert Lupton the Good <rhl@xxxxxxxxxxxxxxxxxxx>:
> I'd much prefer to see eigen use std::vector, and help
> users provide the neeeded specializations -- i.e.
>>
>> or write a dox page on how to
>> manually write a std::vector specialization like we do for Eigen
>> types.
>
> One of eigen's great attractions that it's a light weight,
> no dependencies, way of getting efficient linear algebra
> into standard-compliant C++ codes.  To look forward, it's
> just the sort of library that boost needs.
>
> To add our own nearly-but-not-quite version of part of the
> STL seems to me to go against this principle.

I hear your point. But let's differentiate between 2 things:
1) fiddling with the STL containers in general
2) fiddling with the STL containers only when specialized for Eigen
types, and only to work around a plain bug in the current c++ standard
that is anyway being fixed in the next c++ standard.

The problem that Markus hit, is that Eigen 2.0.1 does 1) when the
intention was really to do 2). If we can instead to 2) strictly, then
I think that's OK.

The std::vector from the c++98 standard is plain useless for
fixed-size vectorizable eigen types because the alignment qualifiers
are discarded when the object is passed by value to resize().

Cheers,
Benoit