vtk-m/vtkm/exec/arg/FromCount.h
Kenneth Moreland 99ce66c6fe Change Fetches to use ThreadIndices instead of Invocation.
Previously, all Fetch objects received an Invocation object in their
Load and Store methods. The point of this was that it allowed the Fetch
to get data from any of the execution objects. However, every Fetch
either just got data directly from its associated execution object or
else used a secondary execution object (the input domain) to get indices
into their own execution object.

This left two potential areas for improvement. First, pulling data out
of the Invocation object was unnecessarily complicated. It would be much
nicer to get data directly from the associated execution object. Second,
when getting index information from the input domain, it was often the
case that extra computations were necessary (particularly on structured
cell sets). There was no way to share the index information among
Fetches, and therefore the computations were replicated.

This change removes the Invocation from the Fetch Load and Store.
Instead, it passes the associated execution object and a new object type
called the ThreadIndices. The ThreadIndices are customized for the input
domain and therefore have all the information needed for a redirected
lookup. It is also a thread-local object so it can cache computed
indices and save on computation time.
2015-10-07 17:01:42 -06:00

86 lines
2.8 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.
//
// Copyright 2014 Sandia Corporation.
// Copyright 2014 UT-Battelle, LLC.
// Copyright 2014 Los Alamos National Security.
//
// Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
// the U.S. Government retains certain rights in this software.
//
// Under the terms of Contract DE-AC52-06NA25396 with Los Alamos National
// Laboratory (LANL), the U.S. Government retains certain rights in
// this software.
//============================================================================
#ifndef vtk_m_exec_arg_FromCount_h
#define vtk_m_exec_arg_FromCount_h
#include <vtkm/exec/arg/Fetch.h>
#include <vtkm/exec/arg/ExecutionSignatureTagBase.h>
#include <vtkm/exec/arg/ThreadIndicesTopologyMap.h>
namespace vtkm {
namespace exec {
namespace arg {
/// \brief Aspect tag to use for getting the from count.
///
/// The \c AspectTagFromCount aspect tag causes the \c Fetch class to obtain
/// the number of indices that map to the current topology element.
///
struct AspectTagFromCount { };
/// \brief The \c ExecutionSignature tag to get the number of from elements.
///
/// In a topology map, there are \em from and \em to topology elements
/// specified. The scheduling occurs on the \em to elements, and for each \em
/// to element there is some number of incident \em from elements that are
/// accessible. This \c ExecutionSignature tag provides the number of these \em
/// from elements that are accessible.
///
struct FromCount : vtkm::exec::arg::ExecutionSignatureTagBase
{
static const vtkm::IdComponent INDEX = 1;
typedef vtkm::exec::arg::AspectTagFromCount AspectTag;
};
template<typename FetchTag,
typename ConnectivityType,
typename ExecObjectType>
struct Fetch<FetchTag,
vtkm::exec::arg::AspectTagFromCount,
vtkm::exec::arg::ThreadIndicesTopologyMap<ConnectivityType>,
ExecObjectType>
{
typedef vtkm::exec::arg::ThreadIndicesTopologyMap<ConnectivityType>
ThreadIndicesType;
typedef vtkm::IdComponent ValueType;
VTKM_SUPPRESS_EXEC_WARNINGS
VTKM_EXEC_EXPORT
ValueType Load(const ThreadIndicesType &indices, const ExecObjectType &) const
{
return indices.GetIndicesFrom().GetNumberOfComponents();
}
VTKM_EXEC_EXPORT
void Store(const ThreadIndicesType &,
const ExecObjectType &,
const ValueType &) const
{
// Store is a no-op.
}
};
}
}
} // namespace vtkm::exec::arg
#endif //vtk_m_exec_arg_FromCount_h