eigen allocation bug in tasks, rbdyn, sva, etc #23
Description
It seems there is a small flaw in many of the classes as per the eigen documentation on memory alignment:
They should all be declaring the following:
class Foo
{
...
Eigen::Vector2d v;
...
public:
EIGEN_MAKE_ALIGNED_OPERATOR_NEW
};
...
Foo *foo = new Foo;
This problem only crops up sporadically in practice but when it does nothing runs! I might submit a pull request fixing this in quite a few places.
The same applies to all STL containers, their allocator must be set:
Using an aligned allocator
STL containers take an optional template parameter, the allocator type. When using STL containers on fixed-size vectorizable Eigen types, you need tell the container to use an allocator that will always allocate memory at 16-byte-aligned locations. Fortunately, Eigen does provide such an allocator: Eigen::aligned_allocator.
For example, instead of
std::map<int, Eigen::Vector4f>
you need to use
std::map<int, Eigen::Vector4f, std::less<int>,
Eigen::aligned_allocator<std::pair<const int, Eigen::Vector4f> > >
Note that the third parameter "std::less<int>" is just the default value, but we have to include it because we want to specify the fourth parameter, which is the allocator type.
The case of std::vector
The situation with std::vector was even worse (explanation below) so we had to specialize it for the Eigen::aligned_allocator type. In practice you must use the Eigen::aligned_allocator (not another aligned allocator), and #include <Eigen/StdVector>.
Here is an example:
#include<Eigen/StdVector>
/* ... */
std::vector<Eigen::Vector4f,Eigen::aligned_allocator<Eigen::Vector4f> >