This class holds a Vec and exposes some number of components. The class
is used when you need a Vec of a size that is not known at compile time
but that a maximum length of reasonable size is known.
Some changes to the Vec class and VecTraits in anticipation of creating
Vec-like objects. The following changes are made:
* Add GetNumberOfComponents to Vec, which returns NUM_COMPONENTS.
* Likewise, all VecTraits have a GetNumberOfComponents method.
* The ToVec method in VecTraits is changed to CopyInto so that it can be
used when the length of the Vec-like is not known. CopyInto is also
added to Vec.
* VecTraits has a typedef named IsSizeStatic which is set to
VecTraitsTagSizeStatic when the number of components is known at compile
time and VecTraitsTagSizeVariable when the number of components is not
known until runtime.
C and C++ has a funny feature where operations on small integers (char
and short) actually promote the result to a 32 bit integer. Most often
in our code the result is pushed back to the same type, and picky compilers
can then give a warning about an implicit type conversion (that we
inevitably don't care about). Here are a lot of changes to suppress
the warnings.
Robert Maynard pointed out that the unary operator- I added to Vec could
lead to undesirable behavior for vectors of unsigned integer types. This
changed makes the definition of operator- conditional on the component
type being either a signed integer or a float type.
I also added some more actual testing of the new operator.
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.
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.
