The ArrayHandle classes all exclusively work in the control environment.
However, CUDA likes to add __device__ to constructors, destructors, and
assignment operators it automatically adds. This in turn causes warnings
about the __device__ function using host-only classes (like
boost::shared_ptr). Solve this problem by adding explicit methods for
all of these.
Implemented this by wrapping up all these default objects in a macro.
This also solved the problem of other constructors that are necessary
for array handles such as a constructor that takes the base array
handle.
Under CUDA, the default constructors and destructors created are exported
as __host__ and __device__, which causes problems because they used a boost
pointer that only works on the host. The explicit copy constructors and
destructors do the same thing as the default ones except declared to only
work on the host.
Instead of having a single specialization for sort and zip handles,
we know handle any fancy handles being passed to the cuda device adapter.
This was done by reworking how we represent fancy iterators inside thrust,
and instead of using a transform iterator + counting iterator we just use
a iterator_facade.
