The old atomic compare and swap operations (`vtkm::AtomicCompareAndSwap`
and `vtkm::exec::AtomicArrayExecutionObject::CompareAndSwap`) had an
order of arguments that was confusing. The order of the arguments was
shared pointer (or index), desired value, expected value. Most people
probably assume expected value comes before desired value. And this
order conflicts with the order in the `std` methods, GCC atomics, and
Kokkos.
Change the interface of atomic operations to be patterned off the
`std::atomic_compare_exchange` and `std::atomic<T>::compare_exchange`
methods. First, these methods have a more intuitive order of parameters
(shared pointer, expected, desired). Second, rather than take a value
for the expected and return the actual old value, they take a pointer to
the expected value (or reference in `AtomicArrayExecutionObject`) and
modify this value in the case that it does not match the actual value.
This makes it harder to mix up the expected and desired parameters.
Also, because the methods return a bool indicating whether the value was
changed, there is an additional benefit that compare-exchange loops are
implemented easier.
For example, consider you want to apply the function `MyOp` on a
`sharedValue` atomically. With the old interface, you would have to do
something like this.
```cpp
T oldValue;
T newValue;
do
{
oldValue = *sharedValue;
newValue = MyOp(oldValue);
} while (vtkm::AtomicCompareAndSwap(sharedValue, newValue, oldValue) != oldValue);
```
With the new interface, this is simplfied to this.
```cpp
T oldValue = *sharedValue;
while (!vtkm::AtomicCompareExchange(sharedValue, &oldValue, MyOp(oldValue));
```
When you invoke a worklet, a scoped performance log is automatically
generated. The previous version gave the name of the worklet, which is
technically everything you need to know. However, it is also convenient
to know what type of worklet it is (e.g. a field map worklet or a
topology map worklet). This can be determined by looking at the
definition of the worklet in the source code, but that is not practical
if, for example, you want to perform automated analysis.
This change prints out the type of the dispatcher instead of the
worklet. The full type of the dispatcher includes the worklet as a
template parameter, so you get both the dispatcher/worklet type and the
worklet itself. So previously you would get log lines like
```
Invoking Worklet: 'vtkm::worklet::vtkm::worklet::ExternalFaces::NumFacesPerCell'
```
They now look like this:
```
Invoking Worklet: 'vtkm::worklet::DispatcherMapTopology<vtkm::worklet::ExternalFaces::NumFacesPerCell>'
```
Previously, the `TransferFunction` worklet required you to call
`PrepareForExecution` on the `ColorTable` and give that to the
constructor. Bad things can happen if the `ColorTable` used in the
constructor does not match the device the worklet actually gets invoked
on. Change this to make the `ColorTable` a worklet argument of type
`ExecObj`. The dispatcher will automatically call
`ColorTable::PrepareForInput` and guarantee that the devices match.
Virtual methods are being deprecated, so remove their use from the
ColorTable classes. Instead of using a virtual method to look up a value
in the ColorTable, we essentially use a switch statement. This change
also simplified the code quite a bit.
The execution object used to use pointers to handle the virtual objects.
That is no longer necessary, so a simple `vtkm::exec::ColorTable` is
returned for execution objects. (Note that this `ColorTable` contains
pointers that are specific for the particular device.) This is a non-
backward compabible change. However, the only place (outside of the
`ColorTable` implementation itself) was a single worklet for converting
scalars to colors (`vtkm::worklet::colorconversion::TransferFunction`).
This is unlikely to affect anyone.
I also "fixed" some names in enum structs. There has been some
inconsistencies in VTK-m on whether items in an enum struct are
capitolized or camel case. We seem to moving toward camel case, so
deprecate some old names.
e706880d7 Fix unnecessary deprecation warnings in visual studio
f7cc03107 Fix deprecated warnings
b27e4c7ea Ignore files for deprecated virtual classes for SourceInInstall test
284774cf4 Turn on "no virtual" option on some CI builds
cd08fd499 Add changelog for removing virtual methods
63ef84ed7 Optionally remove all use of ArrayHandleVirtual
e11f612ad Deprecate ArrayHandleVirtual
Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: Robert Maynard <robert.maynard@kitware.com>
Merge-request: !2256
As we remove more and more virtual methods from VTK-m, I expect several
users will be interested in completely removing them from the build for
several reasons.
1. They may be compiling for hardware that does not support virtual
methods.
2. They may need to compile for CUDA but need shared libraries.
3. It should go a bit faster.
To enable this, a CMake option named `VTKm_NO_DEPRECATED_VIRTUAL` is
added. It defaults to `OFF`. But when it is `ON`, none of the code that
both uses virtuals and is deprecated will be built.
Currently, only `ArrayHandleVirtual` is deprecated, so the rest of the
virtual classes will still be built. As we move forward, more will be
removed until all virtual method functionality is removed.
The parallel sorts in the device adapter are documented to not be
stable. Up until recently, the sorts for all the supported devices
happened to be stable (or at least provided a stable sort where needed).
However, the recent Kokkos adapter provides a sort that is no stable.
This broke some tests that relied on stable sorts when they should not
have.
Fix the tests that relied on stable sort to check the results.
The testing helper class provided a method named `GetTestDataBasePath`
that returned the base path to all the data files stored in the VTK-m
repo. This is fine, but it was a little cumbersome to build filenames.
To make things easier, there is now a new method named `DataPath` that
takes a string of the filename (or, rather, subpath) to the file in that
directory and automatically builds the path to it.
