vtk-m/vtkm/worklet/testing/UnitTestCrossProduct.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

119 lines
4.4 KiB
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/CrossProduct.h>
#include <vtkm/worklet/DispatcherMapField.h>
#include <random>
#include <vtkm/cont/testing/Testing.h>
namespace
{
std::mt19937 randGenerator;
template <typename T>
void createVectors(std::vector<vtkm::Vec<T, 3>>& vecs1, std::vector<vtkm::Vec<T, 3>>& vecs2)
{
// First, test the standard directions.
// X x Y
vecs1.push_back(vtkm::make_Vec(1, 0, 0));
vecs2.push_back(vtkm::make_Vec(0, 1, 0));
// Y x Z
vecs1.push_back(vtkm::make_Vec(0, 1, 0));
vecs2.push_back(vtkm::make_Vec(0, 0, 1));
// Z x X
vecs1.push_back(vtkm::make_Vec(0, 0, 1));
vecs2.push_back(vtkm::make_Vec(1, 0, 0));
// Y x X
vecs1.push_back(vtkm::make_Vec(0, 1, 0));
vecs2.push_back(vtkm::make_Vec(1, 0, 0));
// Z x Y
vecs1.push_back(vtkm::make_Vec(0, 0, 1));
vecs2.push_back(vtkm::make_Vec(0, 1, 0));
// X x Z
vecs1.push_back(vtkm::make_Vec(1, 0, 0));
vecs2.push_back(vtkm::make_Vec(0, 0, 1));
//Test some other vector combinations
std::uniform_real_distribution<vtkm::Float64> randomDist(-10.0, 10.0);
for (int i = 0; i < 100; i++)
{
vecs1.push_back(vtkm::make_Vec(
randomDist(randGenerator), randomDist(randGenerator), randomDist(randGenerator)));
vecs2.push_back(vtkm::make_Vec(
randomDist(randGenerator), randomDist(randGenerator), randomDist(randGenerator)));
}
}
template <typename T>
void TestCrossProduct()
{
std::vector<vtkm::Vec<T, 3>> inputVecs1, inputVecs2;
createVectors(inputVecs1, inputVecs2);
vtkm::cont::ArrayHandle<vtkm::Vec<T, 3>> inputArray1, inputArray2;
vtkm::cont::ArrayHandle<vtkm::Vec<T, 3>> outputArray;
inputArray1 = vtkm::cont::make_ArrayHandle(inputVecs1, vtkm::CopyFlag::Off);
inputArray2 = vtkm::cont::make_ArrayHandle(inputVecs2, vtkm::CopyFlag::Off);
vtkm::worklet::CrossProduct crossProductWorklet;
vtkm::worklet::DispatcherMapField<vtkm::worklet::CrossProduct> dispatcherCrossProduct(
crossProductWorklet);
dispatcherCrossProduct.Invoke(inputArray1, inputArray2, outputArray);
VTKM_TEST_ASSERT(outputArray.GetNumberOfValues() == inputArray1.GetNumberOfValues(),
"Wrong number of results for CrossProduct worklet");
//Test the canonical cases.
VTKM_TEST_ASSERT(test_equal(outputArray.ReadPortal().Get(0), vtkm::make_Vec(0, 0, 1)) &&
test_equal(outputArray.ReadPortal().Get(1), vtkm::make_Vec(1, 0, 0)) &&
test_equal(outputArray.ReadPortal().Get(2), vtkm::make_Vec(0, 1, 0)) &&
test_equal(outputArray.ReadPortal().Get(3), vtkm::make_Vec(0, 0, -1)) &&
test_equal(outputArray.ReadPortal().Get(4), vtkm::make_Vec(-1, 0, 0)) &&
test_equal(outputArray.ReadPortal().Get(5), vtkm::make_Vec(0, -1, 0)),
"Wrong result for CrossProduct worklet");
for (vtkm::Id i = 0; i < inputArray1.GetNumberOfValues(); i++)
{
vtkm::Vec<T, 3> v1 = inputArray1.ReadPortal().Get(i);
vtkm::Vec<T, 3> v2 = inputArray2.ReadPortal().Get(i);
vtkm::Vec<T, 3> res = outputArray.ReadPortal().Get(i);
//Make sure result is orthogonal each input vector. Need to normalize to compare with zero.
vtkm::Vec<T, 3> v1N(vtkm::Normal(v1)), v2N(vtkm::Normal(v1)), resN(vtkm::Normal(res));
VTKM_TEST_ASSERT(test_equal(vtkm::Dot(resN, v1N), T(0.0)), "Wrong result for cross product");
VTKM_TEST_ASSERT(test_equal(vtkm::Dot(resN, v2N), T(0.0)), "Wrong result for cross product");
T sinAngle = vtkm::Magnitude(res) * vtkm::RMagnitude(v1) * vtkm::RMagnitude(v2);
T cosAngle = vtkm::Dot(v1, v2) * vtkm::RMagnitude(v1) * vtkm::RMagnitude(v2);
VTKM_TEST_ASSERT(test_equal(sinAngle * sinAngle + cosAngle * cosAngle, T(1.0)),
"Bad cross product length.");
}
}
void TestCrossProductWorklets()
{
std::cout << "Testing CrossProduct Worklet" << std::endl;
TestCrossProduct<vtkm::Float32>();
TestCrossProduct<vtkm::Float64>();
}
}
int UnitTestCrossProduct(int argc, char* argv[])
{
return vtkm::cont::testing::Testing::Run(TestCrossProductWorklets, argc, argv);
}