vtk-m/vtkm/worklet/testing/UnitTestScatterCounting.cxx
Kenneth Moreland d1a4aecc59 Improvements to moving data into ArrayHandle
We have made several improvements to adding data into an `ArrayHandle`.

## Moving data from an `std::vector`

For numerous reasons, it is convenient to define data in a `std::vector`
and then wrap that into an `ArrayHandle`. It is often the case that an
`std::vector` is filled and then becomes unused once it is converted to an
`ArrayHandle`. In this case, what we really want is to pass the data off to
the `ArrayHandle` so that the `ArrayHandle` is now managing the data and
not the `std::vector`.

C++11 has a mechanism to do this: move semantics. You can now pass
variables to functions as an "rvalue" (right-hand value). When something is
passed as an rvalue, it can pull state out of that variable and move it
somewhere else. `std::vector` implements this movement so that an rvalue
can be moved to another `std::vector` without actually copying the data.
`make_ArrayHandle` now also takes advantage of this feature to move rvalue
`std::vector`s.

There is a special form of `make_ArrayHandle` named `make_ArrayHandleMove`
that takes an rvalue. There is also a special overload of
`make_ArrayHandle` itself that handles an rvalue `vector`. (However, using
the explicit move version is better if you want to make sure the data is
actually moved.)

## Make `ArrayHandle` from initalizer list

A common use case for using `std::vector` (particularly in our unit tests)
is to quickly add an initalizer list into an `ArrayHandle`. Now you can
by simply passing an initializer list to `make_ArrayHandle`.

## Deprecated `make_ArrayHandle` with default shallow copy

For historical reasons, passing an `std::vector` or a pointer to
`make_ArrayHandle` does a shallow copy (i.e. `CopyFlag` defaults to `Off`).
Although more efficient, this mode is inherintly unsafe, and making it the
default is asking for trouble.

To combat this, calling `make_ArrayHandle` without a copy flag is
deprecated. In this way, if you wish to do the faster but more unsafe
creation of an `ArrayHandle` you should explicitly express that.

This requried quite a few changes through the VTK-m source (particularly in
the tests).

## Similar changes to `Field`

`vtkm::cont::Field` has a `make_Field` helper function that is similar to
`make_ArrayHandle`. It also features the ability to create fields from
`std::vector`s and C arrays. It also likewise had the same unsafe behavior
by default of not copying from the source of the arrays.

That behavior has similarly been depreciated. You now have to specify a
copy flag.

The ability to construct a `Field` from an initializer list of values has
also been added.
2020-07-23 10:53:38 -06:00

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C++

//============================================================================
// Copyright (c) Kitware, Inc.
// All rights reserved.
// See LICENSE.txt for details.
//
// This software is distributed WITHOUT ANY WARRANTY; without even
// the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
// PURPOSE. See the above copyright notice for more information.
//============================================================================
#include <vtkm/worklet/ScatterCounting.h>
#include <vtkm/cont/ArrayHandle.h>
#include <vtkm/cont/DeviceAdapterAlgorithm.h>
#include <vtkm/worklet/DispatcherMapField.h>
#include <vtkm/worklet/WorkletMapField.h>
#include <vtkm/cont/testing/Testing.h>
#include <vector>
namespace
{
struct TestScatterArrays
{
vtkm::cont::ArrayHandle<vtkm::IdComponent> CountArray;
vtkm::cont::ArrayHandle<vtkm::Id> InputToOutputMap;
vtkm::cont::ArrayHandle<vtkm::Id> OutputToInputMap;
vtkm::cont::ArrayHandle<vtkm::IdComponent> VisitArray;
};
TestScatterArrays MakeScatterArraysShort()
{
TestScatterArrays arrays;
arrays.CountArray = vtkm::cont::make_ArrayHandle<vtkm::IdComponent>(
{ 1, 2, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0 });
arrays.InputToOutputMap = vtkm::cont::make_ArrayHandle<vtkm::Id>(
{ 0, 1, 3, 3, 3, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6 });
arrays.OutputToInputMap = vtkm::cont::make_ArrayHandle<vtkm::Id>({ 0, 1, 1, 4, 6, 14 });
arrays.VisitArray = vtkm::cont::make_ArrayHandle<vtkm::IdComponent>({ 0, 0, 1, 0, 0, 0 });
return arrays;
}
TestScatterArrays MakeScatterArraysLong()
{
TestScatterArrays arrays;
arrays.CountArray = vtkm::cont::make_ArrayHandle<vtkm::IdComponent>({ 0, 1, 2, 3, 4, 5 });
arrays.InputToOutputMap = vtkm::cont::make_ArrayHandle<vtkm::Id>({ 0, 0, 1, 3, 6, 10 });
arrays.OutputToInputMap =
vtkm::cont::make_ArrayHandle<vtkm::Id>({ 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5 });
arrays.VisitArray = vtkm::cont::make_ArrayHandle<vtkm::IdComponent>(
{ 0, 0, 1, 0, 1, 2, 0, 1, 2, 3, 0, 1, 2, 3, 4 });
return arrays;
}
TestScatterArrays MakeScatterArraysZero()
{
TestScatterArrays arrays;
arrays.CountArray = vtkm::cont::make_ArrayHandle<vtkm::IdComponent>({ 0, 0, 0, 0, 0, 0 });
arrays.InputToOutputMap = vtkm::cont::make_ArrayHandle<vtkm::Id>({ 0, 0, 0, 0, 0, 0 });
arrays.OutputToInputMap.Allocate(0);
arrays.VisitArray.Allocate(0);
return arrays;
}
struct TestScatterCountingWorklet : public vtkm::worklet::WorkletMapField
{
using ControlSignature = void(FieldIn inputIndices,
FieldOut copyIndices,
FieldOut recordVisit,
FieldOut recordWorkId);
using ExecutionSignature = void(_1, _2, _3, _4, VisitIndex, WorkIndex);
using ScatterType = vtkm::worklet::ScatterCounting;
template <typename CountArrayType>
VTKM_CONT static ScatterType MakeScatter(const CountArrayType& countArray)
{
return ScatterType(countArray);
}
VTKM_EXEC
void operator()(vtkm::Id inputIndex,
vtkm::Id& indexCopy,
vtkm::IdComponent& writeVisit,
vtkm::Float32& captureWorkId,
vtkm::IdComponent visitIndex,
vtkm::Id workId) const
{
indexCopy = inputIndex;
writeVisit = visitIndex;
captureWorkId = TestValue(workId, vtkm::Float32());
}
};
template <typename T>
void CompareArrays(vtkm::cont::ArrayHandle<T> array1, vtkm::cont::ArrayHandle<T> array2)
{
using PortalType = typename vtkm::cont::ArrayHandle<T>::ReadPortalType;
PortalType portal1 = array1.ReadPortal();
PortalType portal2 = array2.ReadPortal();
VTKM_TEST_ASSERT(portal1.GetNumberOfValues() == portal2.GetNumberOfValues(),
"Arrays are not the same length.");
for (vtkm::Id index = 0; index < portal1.GetNumberOfValues(); index++)
{
T value1 = portal1.Get(index);
T value2 = portal2.Get(index);
VTKM_TEST_ASSERT(value1 == value2, "Array values not equal.");
}
}
// This unit test makes sure the ScatterCounting generates the correct map
// and visit arrays.
void TestScatterArrayGeneration(const TestScatterArrays& arrays)
{
std::cout << " Testing array generation" << std::endl;
vtkm::worklet::ScatterCounting scatter(
arrays.CountArray, vtkm::cont::DeviceAdapterTagAny(), true);
vtkm::Id inputSize = arrays.CountArray.GetNumberOfValues();
std::cout << " Checking input to output map." << std::endl;
CompareArrays(arrays.InputToOutputMap, scatter.GetInputToOutputMap());
std::cout << " Checking output to input map." << std::endl;
CompareArrays(arrays.OutputToInputMap, scatter.GetOutputToInputMap(inputSize));
std::cout << " Checking visit array." << std::endl;
CompareArrays(arrays.VisitArray, scatter.GetVisitArray(inputSize));
}
// This is more of an integration test that makes sure the scatter works with a
// worklet invocation.
void TestScatterWorklet(const TestScatterArrays& arrays)
{
std::cout << " Testing scatter counting in a worklet." << std::endl;
vtkm::worklet::DispatcherMapField<TestScatterCountingWorklet> dispatcher(
TestScatterCountingWorklet::MakeScatter(arrays.CountArray));
vtkm::Id inputSize = arrays.CountArray.GetNumberOfValues();
vtkm::cont::ArrayHandleIndex inputIndices(inputSize);
vtkm::cont::ArrayHandle<vtkm::Id> outputToInputMapCopy;
vtkm::cont::ArrayHandle<vtkm::IdComponent> visitCopy;
vtkm::cont::ArrayHandle<vtkm::Float32> captureWorkId;
std::cout << " Invoke worklet" << std::endl;
dispatcher.Invoke(inputIndices, outputToInputMapCopy, visitCopy, captureWorkId);
std::cout << " Check output to input map." << std::endl;
CompareArrays(outputToInputMapCopy, arrays.OutputToInputMap);
std::cout << " Check visit." << std::endl;
CompareArrays(visitCopy, arrays.VisitArray);
std::cout << " Check work id." << std::endl;
CheckPortal(captureWorkId.ReadPortal());
}
void TestScatterCountingWithArrays(const TestScatterArrays& arrays)
{
TestScatterArrayGeneration(arrays);
TestScatterWorklet(arrays);
}
void TestScatterCounting()
{
std::cout << "Testing arrays with output smaller than input." << std::endl;
TestScatterCountingWithArrays(MakeScatterArraysShort());
std::cout << "Testing arrays with output larger than input." << std::endl;
TestScatterCountingWithArrays(MakeScatterArraysLong());
std::cout << "Testing arrays with zero output." << std::endl;
TestScatterCountingWithArrays(MakeScatterArraysZero());
}
} // anonymous namespace
int UnitTestScatterCounting(int argc, char* argv[])
{
return vtkm::cont::testing::Testing::Run(TestScatterCounting, argc, argv);
}