Porting the dax device adapter over to vtkm. Unlike the dax version, doesn't
use the thrust::device_vector, but instead uses thrust::system calls so that
we can support multiple thrust based backends.
Also this has Texture Memory support for input array handles. Some more work
will need to be done to ArrayHandle so that everything works when using an
ArrayHandle inplace with texture memory bindings.
Providing these types tends to "lock in" the precision of the algorithms
used in VTK-m. Since we are using templating anyway, our templates
should be generic enough to handle difference precision in the data.
Usually the appropriate type can be determined by the data provided. In
the case where there is no hint on the precision of data to use (for
example, in the code that provides coordinates for uniform data), there
is a vtkm::FloatDefault.
Before we assumed that we would only use the basic types specified by
the widths of vtkm::Scalar and vtkm::Id. We want to expand this to make
sure the code works on whatever data precision we need.
Since we want our code to generally handle data of different precision
(for example either float or double) expand the types in our list types
to include multiple precision.
There are multiple reasons for this name change:
* The name Tuple conflicts with the boost::Tuple class, which as a
different interface and feature set. This gets confusing, especially
since VTK-m uses boost quite a bit.
* The use of this class is usually (although not always) as a
mathematical vector.
* The vtkm::Scalar and vtkm::Vector* classes are going to go away soon
to better support multiple base data type widths. Having this
abbriviated name will hopefully make the code a bit nicer when these
types have to be explicitly specified.
Also modified the implementation a bit to consolidate some of the code.
In preparation for supporting base types with more widths, add typedefs
for the base types with explicit widths (number of bits).
Also added a IdComponent type that should be used for indices for
components into tuples and vectors. There now should be no reason to use
"int" inside of VTK-m code (especially for indexing). This change cleans
up many of the int types that were used throughout.
We made this change a while ago to help with completion in IDEs.
(Completion was matching a bunch of wrapper macros that were almost
never used anywhere.) Most of the changes are in comments, but there are
a few bad macro definitions.
Using alignment on basic types when vtkm only targetted Linux/BSD/OSX was
'okay' because of how the alignment operators worked, but potential was going
to cause issues in the long run if we failed to detect the correct size and the
compiler was than forced to not use intrinsics.
Now with adding windows support we have run into another problem. Basically
using an alignment operator on a typedef means that the type must never
be passed by value, but must always be passed by reference. The reason for
this is that passing by value doesn't respect alignment requirements, and
can cause very subtle errors or crashes.
A really good read for people more interested in these problems:
http://eigen.tuxfamily.org/dox/group__TopicPassingByValue.htmlhttp://eigen.tuxfamily.org/dox-devel/group__DenseMatrixManipulation__Alignement.html
