lsCompareArea.hpp

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#pragma once
 
#include <limits>
#include <unordered_map>
 
#include <hrleDenseCellIterator.hpp>
#include <lsDomain.hpp>
#include <lsExpand.hpp>
#include <lsMesh.hpp>
#include <lsPreCompileMacros.hpp>
 
namespace viennals {
 
using namespace viennacore;

template <class T, int D = 2> class CompareArea {
  using hrleDomainType = typename Domain<T, D>::DomainType;
  using hrleIndexType = viennahrle::IndexType;
 
  SmartPointer<Domain<T, D>> levelSetTarget = nullptr;
  SmartPointer<Domain<T, D>> levelSetSample = nullptr;
  viennahrle::Index<D> minIndex, maxIndex;
 
  unsigned long int differentCellsCount = 0;
  unsigned long int customDifferentCellCount = 0;
 
  hrleIndexType xRangeMin = std::numeric_limits<hrleIndexType>::lowest();
  hrleIndexType xRangeMax = std::numeric_limits<hrleIndexType>::max();
  hrleIndexType yRangeMin = std::numeric_limits<hrleIndexType>::lowest();
  hrleIndexType yRangeMax = std::numeric_limits<hrleIndexType>::max();
  bool useCustomXIncrement = false;
  bool useCustomYIncrement = false;
 
  unsigned short int customXIncrement = 0;
  unsigned short int customYIncrement = 0;
  unsigned short int defaultIncrement = 1;
 
  double gridDelta = 0.0;
 
  // Mesh output related members
  SmartPointer<Mesh<T>> outputMesh = nullptr;
 
  bool checkAndCalculateBounds() {
    if (levelSetTarget == nullptr || levelSetSample == nullptr) {
      Logger::getInstance()
          .addError("Missing level set in CompareArea.")
          .print();
      return false;
    }
 
    // Check if the grids are compatible
    const auto &gridTarget = levelSetTarget->getGrid();
    const auto &gridSample = levelSetSample->getGrid();
 
    if (gridTarget.getGridDelta() != gridSample.getGridDelta()) {
      Logger::getInstance()
          .addError("Grid delta mismatch in CompareArea. The grid deltas of "
                    "the two level sets must be equal.")
          .print();
      return false;
    } else {
      gridDelta = gridTarget.getGridDelta();
    }
 
    // Initialize min and max indices
    for (unsigned i = 0; i < D; ++i) {
      minIndex[i] = std::numeric_limits<hrleIndexType>::max();
      maxIndex[i] = std::numeric_limits<hrleIndexType>::lowest();
    }
 
    // Get the boundaries of the two level sets
    auto &domainTarget = levelSetTarget->getDomain();
    auto &domainSample = levelSetSample->getDomain();
 
    // Calculate actual bounds
    for (unsigned i = 0; i < D; ++i) {
      minIndex[i] = std::min({minIndex[i],
                              (gridTarget.isNegBoundaryInfinite(i))
                                  ? domainTarget.getMinRunBreak(i)
                                  : gridTarget.getMinBounds(i),
                              (gridSample.isNegBoundaryInfinite(i))
                                  ? domainSample.getMinRunBreak(i)
                                  : gridSample.getMinBounds(i)});
 
      maxIndex[i] = std::max({maxIndex[i],
                              (gridTarget.isPosBoundaryInfinite(i))
                                  ? domainTarget.getMaxRunBreak(i)
                                  : gridTarget.getMaxBounds(i),
                              (gridSample.isPosBoundaryInfinite(i))
                                  ? domainSample.getMaxRunBreak(i)
                                  : gridSample.getMaxBounds(i)});
    }
 
    return true;
  }
 
public:
  CompareArea() {
    assert(D == 2 &&
           "CompareArea is currently only implemented for 2D level sets.");
  }
 
  CompareArea(SmartPointer<Domain<T, D>> passedLevelSetTarget,
              SmartPointer<Domain<T, D>> passedLevelSetSample)
      : levelSetTarget(passedLevelSetTarget),
        levelSetSample(passedLevelSetSample) {
    assert(D == 2 &&
           "CompareArea is currently only implemented for 2D level sets.");
  }

  void setLevelSetTarget(SmartPointer<Domain<T, D>> passedLevelSet) {
    levelSetTarget = passedLevelSet;
  }

  void setLevelSetSample(SmartPointer<Domain<T, D>> passedLevelSet) {
    levelSetSample = passedLevelSet;
  }

  void setDefaultIncrement(unsigned short int increment) {
    defaultIncrement = increment;
  }

  void setXRangeAndIncrement(hrleIndexType minXRange, hrleIndexType maxXRange,
                             unsigned short int Xincrement) {
    xRangeMin = minXRange;
    xRangeMax = maxXRange;
    customXIncrement = Xincrement;
    useCustomXIncrement = true;
  }

  void setYRangeAndIncrement(hrleIndexType minYRange, hrleIndexType maxYRange,
                             unsigned short int Yincrement) {
    yRangeMin = minYRange;
    yRangeMax = maxYRange;
    customYIncrement = Yincrement;
    useCustomYIncrement = true;
  }

  void setOutputMesh(SmartPointer<Mesh<T>> passedMesh) {
    outputMesh = passedMesh;
  }

  double getAreaMismatch() const {
    return static_cast<double>(differentCellsCount) * gridDelta * gridDelta;
  }

  double getCustomAreaMismatch() const {
    return static_cast<double>(customDifferentCellCount) * gridDelta *
           gridDelta;
  }

  unsigned long int getCellCount() const { return differentCellsCount; }

  unsigned long int getCustomCellCount() const {
    return customDifferentCellCount;
  }

  void apply() {
    // Calculate the bounds for iteration
    if (!checkAndCalculateBounds()) {
      differentCellsCount =
          std::numeric_limits<unsigned long int>::max(); // Error indicator
      customDifferentCellCount =
          std::numeric_limits<unsigned long int>::max(); // Error indicator
      return;
    }
 
    // Ensure both level sets have sufficient width to avoid floating point
    // arithmetic errors. A new working copy is created if expansion is needed,
    // leaving the original level set unmodified.
    constexpr int minimumWidth = 3;
 
    // Use the original or expanded copies as needed
    auto workingTarget = levelSetTarget;
    auto workingSample = levelSetSample;
 
    if (levelSetTarget->getLevelSetWidth() < minimumWidth) {
      workingTarget = SmartPointer<Domain<T, D>>::New(levelSetTarget);
      Expand<T, D>(workingTarget, minimumWidth).apply();
      VIENNACORE_LOG_INFO("CompareArea: Expanded target level set to width " +
                          std::to_string(minimumWidth) +
                          " to avoid undefined values.");
    }
 
    if (levelSetSample->getLevelSetWidth() < minimumWidth) {
      workingSample = SmartPointer<Domain<T, D>>::New(levelSetSample);
      Expand<T, D>(workingSample, minimumWidth).apply();
      VIENNACORE_LOG_INFO("CompareArea: Expanded sample level set to width " +
                          std::to_string(minimumWidth) +
                          " to avoid undefined values.");
    }
 
    // Set up dense cell iterators for both level sets
    viennahrle::ConstDenseCellIterator<hrleDomainType> itTarget(
        workingTarget->getDomain(), minIndex);
    viennahrle::ConstDenseCellIterator<hrleDomainType> itSample(
        workingSample->getDomain(), minIndex);
 
    differentCellsCount = 0;
    customDifferentCellCount = 0;
 
    // Initialize mesh-related variables if generating a mesh
    const bool generateMesh = outputMesh != nullptr;
    if (generateMesh) {
      // Save the extent of the resulting mesh
      outputMesh->clear();
      for (unsigned i = 0; i < D; ++i) {
        outputMesh->minimumExtent[i] = std::numeric_limits<T>::max();
        outputMesh->maximumExtent[i] = std::numeric_limits<T>::lowest();
      }
    }
 
    // Vector for cell differences and increment values to be inserted in the
    // mesh
    std::vector<T> cellDifference;
    std::vector<T> incrementValues;
    size_t currentPointId = 0;
    std::unordered_map<viennahrle::Index<D>, size_t,
                       typename viennahrle::Index<D>::hash>
        pointIdMapping;
 
    // Iterate through the domain defined by the bounding box
    for (; itTarget.getIndices() < maxIndex; itTarget.next()) {
      itSample.goToIndicesSequential(itTarget.getIndices());
 
      // Compare cell values at the current position
      T centerValueTarget = 0.;
      T centerValueSample = 0.;
 
      // Calculate the average value of the corners for both level sets
      for (int i = 0; i < (1 << D); ++i) {
        centerValueTarget += itTarget.getCorner(i).getValue();
        centerValueSample += itSample.getCorner(i).getValue();
      }
      centerValueTarget /= (1 << D);
      centerValueSample /= (1 << D);
 
      // Determine if cell is inside for each level set
      bool insideTarget = (centerValueTarget <= 0.);
      bool insideSample = (centerValueSample <= 0.);
      bool isDifferent = insideTarget != insideSample;
 
      // Calculate range checks once per cell
      bool inXRange = useCustomXIncrement &&
                      (itTarget.getIndices()[0] * gridDelta >= xRangeMin &&
                       itTarget.getIndices()[0] * gridDelta <= xRangeMax);
      bool inYRange = useCustomYIncrement &&
                      (itTarget.getIndices()[1] * gridDelta >= yRangeMin &&
                       itTarget.getIndices()[1] * gridDelta <= yRangeMax);
 
      // Calculate increment to add based on ranges
      unsigned short int incrementToAdd = defaultIncrement;
      if (inXRange && inYRange) {
        // Apply both increments
        incrementToAdd = customXIncrement + customYIncrement;
      } else if (inXRange) {
        incrementToAdd = customXIncrement;
      } else if (inYRange) {
        incrementToAdd = customYIncrement;
      }
 
      // If cells differ, update the counters
      if (isDifferent) {
        // Always increment simple cell count by 1
        differentCellsCount += 1;
 
        // For custom cell count, apply the calculated increment
        customDifferentCellCount += incrementToAdd;
      }
 
      // For mesh generation, process all cells where at least one level set is
      // inside
      if (generateMesh && (insideTarget || insideSample)) {
        // Material ID: 0 for matching inside, 1 for mismatched
        int difference = isDifferent ? 1 : 0;
 
        std::array<unsigned, 1 << D> voxel;
        bool addVoxel = true;
        // TODO: I think this check whether Voxel is added or not can be removed
 
        // Insert all points of voxel into pointList
        for (unsigned i = 0; i < (1 << D); ++i) {
          viennahrle::Index<D> index;
          for (unsigned j = 0; j < D; ++j) {
            index[j] =
                itTarget.getIndices(j) + itTarget.getCorner(i).getOffset()[j];
            if (index[j] > maxIndex[j]) {
              addVoxel = false;
              break;
            }
          }
          if (addVoxel) {
            auto pointIdValue = std::make_pair(index, currentPointId);
            auto pointIdPair = pointIdMapping.insert(pointIdValue);
            voxel[i] = pointIdPair.first->second;
            if (pointIdPair.second) {
              ++currentPointId;
            }
          } else {
            break;
          }
        }
 
        if (addVoxel) {
          if constexpr (D == 3) {
            std::array<unsigned, 8> hexa{voxel[0], voxel[1], voxel[3],
                                         voxel[2], voxel[4], voxel[5],
                                         voxel[7], voxel[6]};
            outputMesh->hexas.push_back(hexa);
          } else if constexpr (D == 2) {
            std::array<unsigned, 4> quad{voxel[0], voxel[1], voxel[3],
                                         voxel[2]};
            outputMesh->tetras.push_back(quad);
          }
 
          cellDifference.push_back(difference);
 
          // Store increment value (0 if not different)
          incrementValues.push_back(isDifferent ? static_cast<T>(incrementToAdd)
                                                : 0);
        }
      }
    }
 
    // Finalize mesh if generating one
    if (generateMesh && !pointIdMapping.empty()) {
      // Insert points into the mesh
      outputMesh->nodes.resize(pointIdMapping.size());
      for (auto it = pointIdMapping.begin(); it != pointIdMapping.end(); ++it) {
        Vec3D<T> coords;
        for (unsigned i = 0; i < D; ++i) {
          coords[i] = gridDelta * it->first[i];
 
          if (coords[i] < outputMesh->minimumExtent[i]) {
            outputMesh->minimumExtent[i] = coords[i];
          } else if (coords[i] > outputMesh->maximumExtent[i]) {
            outputMesh->maximumExtent[i] = coords[i];
          }
        }
        outputMesh->nodes[it->second] = coords;
      }
 
      // Add cell data to the mesh
      assert(cellDifference.size() == incrementValues.size());
      assert(incrementValues.size() ==
             outputMesh->template getElements<1 << D>().size());
      outputMesh->cellData.insertNextScalarData(cellDifference, "Difference");
      outputMesh->cellData.insertNextScalarData(incrementValues,
                                                "CustomIncrement");
    }
  }
};
 
// Precompile for common precision and dimensions
PRECOMPILE_PRECISION_DIMENSION(CompareArea)
 
} // namespace viennals