Re: [eigen] Fixed-size vectorizable members and std::make_shared

[Christoph Hertzberg <chtz@xxxxxxxxxxxxxxxxxxxxxxxx>]

On 02.04.2013 17:46, Márton Danóczy wrote:
> I just ran into a subtle bug, the solution of which doesn't seem to be
> documented anywhere. If I have a class with a fixed-size, vectorizable
> member, even having defined EIGEN_MAKE_ALIGNED_OPERATOR_NEW, creating a
> shared pointer to it using
>
>      std::shared_ptr<MyClass> x = std::make_shared<MyClass>(42);

Apparently, std::make_shared uses ::new and not MyClass::new, so 
EIGEN_MAKE_ALIGNED_OPERATOR_NEW does not help here. I'm afraid it is not 
possible to specialized std::make_shared from inside the class (or is it 
possible in C++11?).

> Is there a way to put an assertion in some constructor, maybe in that of
> DenseStorage, to check that (this % 16 ==0)? It took me quite some time to
> hunt down this bug...

There is an assertion in every (aligned) matrix constructor checking 
exactly that.
If you are using gcc4.7 and 32bit linux, I guess it is this bug:
http://eigen.tuxfamily.org/bz/show_bug.cgi?id=490


Christoph

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