vtk-m2/vtkm/worklet/contourtree/MergeTree.h

343 lines
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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.
//
// 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.
//============================================================================
// Copyright (c) 2016, Los Alamos National Security, LLC
// All rights reserved.
//
// Copyright 2016. Los Alamos National Security, LLC.
// This software was produced under U.S. Government contract DE-AC52-06NA25396
// for Los Alamos National Laboratory (LANL), which is operated by
// Los Alamos National Security, LLC for the U.S. Department of Energy.
// The U.S. Government has rights to use, reproduce, and distribute this
// software. NEITHER THE GOVERNMENT NOR LOS ALAMOS NATIONAL SECURITY, LLC
// MAKES ANY WARRANTY, EXPRESS OR IMPLIED, OR ASSUMES ANY LIABILITY FOR THE
// USE OF THIS SOFTWARE. If software is modified to produce derivative works,
// such modified software should be clearly marked, so as not to confuse it
// with the version available from LANL.
//
// Additionally, redistribution and use in source and binary forms, with or
// without modification, are permitted provided that the following conditions
// are met:
//
// 1. Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
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// 3. Neither the name of Los Alamos National Security, LLC, Los Alamos
// National Laboratory, LANL, the U.S. Government, nor the names of its
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//
// THIS SOFTWARE IS PROVIDED BY LOS ALAMOS NATIONAL SECURITY, LLC AND
// CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
// BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL LOS ALAMOS
// NATIONAL SECURITY, LLC OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
// THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//============================================================================
// This code is based on the algorithm presented in the paper:
// “Parallel Peak Pruning for Scalable SMP Contour Tree Computation.”
// Hamish Carr, Gunther Weber, Christopher Sewell, and James Ahrens.
// Proceedings of the IEEE Symposium on Large Data Analysis and Visualization
// (LDAV), October 2016, Baltimore, Maryland.
//=======================================================================================
//
// COMMENTS:
//
// If we have computed the merge max & merge saddles correctly, we have substantially
// computed the merge tree already. However, it is not in the same format as we have
// previously represented it - in particular, we have yet to define all the merge arcs
// and the superarcs we have collected are not the same as before - i.e. they are already
// partially collapsed, but not according to the same rule as branch decomposition
// This unit is therefore to get the same result out as before so we can set up an
// automated crosscheck on the computation
//
// Compared to earlier versions, we have made a significant change - the merge tree
// is only computed on critical points, not on the full array. We therefore have a
// final step: to extend it to the full array. To do this, we will keep the initial
// mergeArcs array which records a maximum for each vertex, as we need the information
//
// Each maximum is now labelled with the saddle it is mapped to, or to the global min
// We therefore transfer this information back to the mergeArcs array, so that maxima
// (including saddles) are marked with the (lower) vertex that is the low end of their
// arc
// BIG CHANGE: we can actually reuse the mergeArcs array for the final merge arc, for the
// chain maximum for each (regular) point, and for the merge saddle for maxima. This is
// slightly tricky and has some extra memory traffic, but it avoids duplicating arrays
// unnecessarily
//
// Initially, mergeArcs will be set to an outbound neighbour (or self for extrema), as the
// chainMaximum array used to be.
//
// After chains are built, then it will hold *AN* accessible extremum for each vertex.
//
// During the main processing, when an extremum is assigned a saddle, it will be stored
// here. Regular points will still store pointers to an extremum.
//
// After this is done, if the mergeArc points lower/higher, it is pointing to a saddle.
// Otherwise it is pointing to an extremum.
//
// And after the final pass, it will always point to the next along superarcs.
//
//=======================================================================================
#ifndef vtkm_worklet_contourtree_mergetree_h
#define vtkm_worklet_contourtree_mergetree_h
#include <vtkm/cont/ArrayHandle.h>
#include <vtkm/cont/ArrayHandleConstant.h>
#include <vtkm/cont/DataSet.h>
#include <vtkm/worklet/contourtree/PrintVectors.h>
#include <vtkm/worklet/contourtree/ChainDoubler.h>
#include <vtkm/worklet/contourtree/JoinSuperArcFinder.h>
#include <vtkm/worklet/contourtree/JoinArcConnector.h>
#include <vtkm/worklet/contourtree/VertexMergeComparator.h>
//#define DEBUG_PRINT 1
//#define DEBUG_FUNCTION_ENTRY 1
//#define DEBUG_TIMING 1
namespace vtkm {
namespace worklet {
namespace contourtree {
template <typename T, typename StorageType, typename DeviceAdapter>
class MergeTree
{
public:
typedef typename vtkm::cont::DeviceAdapterAlgorithm<DeviceAdapter> DeviceAlgorithm;
// original data array
const vtkm::cont::ArrayHandle<T,StorageType> &values;
// size of mesh
vtkm::Id nRows, nCols, nSlices, nVertices, nLogSteps;
// whether it is join or split tree
bool isJoinTree;
// vector of arcs representing the merge tree
vtkm::cont::ArrayHandle<vtkm::Id> mergeArcs;
// vector storing an extremum for each vertex
vtkm::cont::ArrayHandle<vtkm::Id> extrema;
// vector storing a saddle for each vertex
vtkm::cont::ArrayHandle<vtkm::Id> saddles;
// merge tree constructor
MergeTree(const vtkm::cont::ArrayHandle<T,StorageType> &Values,
vtkm::Id NRows,
vtkm::Id NCols,
vtkm::Id NSlices,
bool IsJoinTree);
// routine that does pointer-doubling in the mergeArc array
void BuildRegularChains();
// routine that computes the augmented merge tree superarcs from the merge graph
void ComputeAugmentedSuperarcs();
// routine that computes the augmented merge arcs from the superarcs
// this is separate from the previous routine because it also gets called separately
// once saddle & extrema are set for a given set of vertices, the merge arcs can be
// computed for any subset of those vertices that contains all of the critical points
void ComputeAugmentedArcs(vtkm::cont::ArrayHandle<vtkm::Id> &vertices);
// debug routine
void DebugPrint(const char *message);
};
// creates merge tree
template <typename T, typename StorageType, typename DeviceAdapter>
MergeTree<T,StorageType,DeviceAdapter>::MergeTree(
const vtkm::cont::ArrayHandle<T,StorageType> &Values,
vtkm::Id NRows,
vtkm::Id NCols,
vtkm::Id NSlices,
bool IsJoinTree) :
values(Values),
nRows(NRows),
nCols(NCols),
nSlices(NSlices),
isJoinTree(IsJoinTree)
{
nVertices = nRows * nCols * nSlices;
nLogSteps = 1;
for (vtkm::Id shifter = nVertices; shifter != 0; shifter >>= 1)
nLogSteps++;
vtkm::cont::ArrayHandleConstant<vtkm::Id> nullArray(0, nVertices);
mergeArcs.Allocate(nVertices);
extrema.Allocate(nVertices);
saddles.Allocate(nVertices);
DeviceAlgorithm::Copy(nullArray, mergeArcs);
DeviceAlgorithm::Copy(nullArray, extrema);
DeviceAlgorithm::Copy(nullArray, saddles);
}
// routine that does pointer-doubling in the saddles array
template<typename T, typename StorageType, typename DeviceAdapter>
void MergeTree<T,StorageType,DeviceAdapter>::BuildRegularChains()
{
#ifdef DEBUG_FUNCTION_ENTRY
std::cout << std::endl;
std::cout << "====================" << std::endl;
std::cout << "Build Regular Chains" << std::endl;
std::cout << "====================" << std::endl;
std::cout << std::endl;
#endif
// 2. Create a temporary array so that we can alternate writing between them
vtkm::cont::ArrayHandle<vtkm::Id> temporaryArcs;
temporaryArcs.Allocate(nVertices);
vtkm::cont::ArrayHandleIndex vertexIndexArray(nVertices);
ChainDoubler chainDoubler;
vtkm::worklet::DispatcherMapField<ChainDoubler> chainDoublerDispatcher(chainDoubler);
// 3. Apply pointer-doubling to build chains to maxima, rocking between two arrays
for (vtkm::Id logStep = 0; logStep < nLogSteps; logStep++)
{
chainDoublerDispatcher.Invoke(vertexIndexArray, // input
extrema); // i/o whole array
}
} // BuildRegularChains()
// routine that computes the augmented merge tree from the merge graph
template <typename T, typename StorageType, typename DeviceAdapter>
void MergeTree<T,StorageType,DeviceAdapter>::ComputeAugmentedSuperarcs()
{
#ifdef DEBUG_FUNCTION_ENTRY
std::cout << std::endl;
std::cout << "=================================" << std::endl;
std::cout << "Compute Augmented Merge Superarcs" << std::endl;
std::cout << "=================================" << std::endl;
std::cout << std::endl;
#endif
// our first step is to assign every vertex to a pseudo-extremum based on how the
// vertex ascends to a extremum, and the sequence of pruning for the extremum
// to do this, we iterate as many times as pruning occurred
// we run a little loop for each element until it finds its join superarc
// expressed as a functor.
vtkm::Id nExtrema = extrema.GetNumberOfValues();
JoinSuperArcFinder<T> joinSuperArcFinder(isJoinTree);
vtkm::worklet::DispatcherMapField<JoinSuperArcFinder<T> >
joinSuperArcFinderDispatcher(joinSuperArcFinder);
vtkm::cont::ArrayHandleIndex vertexIndexArray(nExtrema);
joinSuperArcFinderDispatcher.Invoke(vertexIndexArray, // input
values, // input (whole array)
saddles, // i/o (whole array)
extrema); // i/o (whole array)
// at the end of this, all vertices should have a pseudo-extremum in the extrema array
// and a pseudo-saddle in the saddles array
#ifdef DEBUG_PRINT
DebugPrint("Merge Superarcs Set");
#endif
} // ComputeAugmentedSuperarcs()
// routine that computes the augmented merge arcs from the superarcs
// this is separate from the previous routine because it also gets called separately
// once saddle & extrema are set for a given set of vertices, the merge arcs can be
// computed for any subset of those vertices that contains all of the critical points
template <typename T, typename StorageType, typename DeviceAdapter>
void MergeTree<T,StorageType,DeviceAdapter>::ComputeAugmentedArcs(
vtkm::cont::ArrayHandle<vtkm::Id> &vertices)
{
#ifdef DEBUG_FUNCTION_ENTRY
std::cout << std::endl;
std::cout << "============================" << std::endl;
std::cout << "Compute Augmented Merge Arcs" << std::endl;
std::cout << "============================" << std::endl;
std::cout << std::endl;
#endif
// create a vector of indices for sorting
vtkm::Id nCriticalVerts = vertices.GetNumberOfValues();
vtkm::cont::ArrayHandle<vtkm::Id> vertexSorter;
DeviceAlgorithm::Copy(vertices, vertexSorter);
// We sort by pseudo-maximum to establish the extents
DeviceAlgorithm::Sort(vertexSorter,
VertexMergeComparator<T,StorageType,DeviceAdapter>(
values.PrepareForInput(DeviceAdapter()),
extrema.PrepareForInput(DeviceAdapter()),
isJoinTree));
#ifdef DEBUG_PRINT
DebugPrint("Sorting Complete");
#endif
vtkm::cont::ArrayHandleConstant<vtkm::Id> noVertArray(NO_VERTEX_ASSIGNED, nVertices);
DeviceAlgorithm::Copy(noVertArray, mergeArcs);
vtkm::cont::ArrayHandleIndex critVertexIndexArray(nCriticalVerts);
JoinArcConnector joinArcConnector;
vtkm::worklet::DispatcherMapField<JoinArcConnector>
joinArcConnectorDispatcher(joinArcConnector);
joinArcConnectorDispatcher.Invoke(critVertexIndexArray, // input
vertexSorter, // input (whole array)
extrema, // input (whole array)
saddles, // input (whole array)
mergeArcs); // output (whole array)
#ifdef DEBUG_PRINT
DebugPrint("Augmented Arcs Set");
#endif
} // ComputeAugmentedArcs()
// debug routine
template<typename T, typename StorageType, typename DeviceAdapter>
void MergeTree<T,StorageType,DeviceAdapter>::DebugPrint(const char *message)
{
std::cout << "---------------------------" << std::endl;
std::cout << std::string(message) << std::endl;
std::cout << "---------------------------" << std::endl;
std::cout << std::endl;
printLabelledBlock("Values", values, nRows*nSlices, nCols);
std::cout << std::endl;
printLabelledBlock("MergeArcs", mergeArcs, nRows, nCols);
std::cout << std::endl;
printLabelledBlock("Extrema", extrema, nRows, nCols);
std::cout << std::endl;
printLabelledBlock("Saddles", saddles, nRows, nCols);
std::cout << std::endl;
} // DebugPrint()
}
}
}
#endif