ExtractStructured now compiles quicker and with less compiler memory

Previously ExtractStructured filter would take ~45sec to compile
with gcc 9.2 and now takes ~15sec.

vtkm/Range.h

@@ -177,7 +177,7 @@ inline VTKM_CONT std::ostream& operator<<(std::ostream& stream, const vtkm::Rang
 {
   return stream << "[" << range.Min << ".." << range.Max << "]";
 } // Declared inside of vtkm namespace so that the operator work with ADL lookup
-
 } // namespace vtkm
 
+
 #endif //vtk_m_Range_h

vtkm/RangeId.h

@@ -131,13 +131,12 @@ struct RangeId
   }
 };
 
-} // namespace vtkm
-
 /// Helper function for printing ranges during testing
 ///
 static inline VTKM_CONT std::ostream& operator<<(std::ostream& stream, const vtkm::RangeId& range)
 {
   return stream << "[" << range.Min << ".." << range.Max << ")";
-}
+} // Declared inside of vtkm namespace so that the operator work with ADL lookup
+} // namespace vtkm
 
 #endif // vtk_m_RangeId_h

vtkm/RangeId2.h

@@ -142,6 +142,32 @@ struct RangeId2
   {
     return ((this->X != range.X) || (this->Y != range.Y));
   }
+
+  VTKM_EXEC_CONT
+  vtkm::RangeId& operator[](IdComponent c) noexcept
+  {
+    if (c <= 0)
+    {
+      return this->X;
+    }
+    else
+    {
+      return this->Y;
+    }
+  }
+
+  VTKM_EXEC_CONT
+  const vtkm::RangeId& operator[](IdComponent c) const noexcept
+  {
+    if (c <= 0)
+    {
+      return this->X;
+    }
+    else
+    {
+      return this->Y;
+    }
+  }
 };
 
 } // namespace vtkm

vtkm/RangeId3.h

@@ -158,15 +158,47 @@ struct RangeId3
   {
     return ((this->X != range.X) || (this->Y != range.Y) || (this->Z != range.Z));
   }
-};
+  VTKM_EXEC_CONT
+  vtkm::RangeId& operator[](IdComponent c) noexcept
+  {
+    if (c <= 0)
+    {
+      return this->X;
+    }
+    else if (c == 1)
+    {
+      return this->Y;
+    }
+    else
+    {
+      return this->Z;
+    }
+  }
 
-} // namespace vtkm
+  VTKM_EXEC_CONT
+  const vtkm::RangeId& operator[](IdComponent c) const noexcept
+  {
+    if (c <= 0)
+    {
+      return this->X;
+    }
+    else if (c == 1)
+    {
+      return this->Y;
+    }
+    else
+    {
+      return this->Z;
+    }
+  }
+};
 
 /// Helper function for printing range during testing
 ///
-static inline VTKM_CONT std::ostream& operator<<(std::ostream& stream, const vtkm::RangeId3& range)
+inline VTKM_CONT std::ostream& operator<<(std::ostream& stream, const vtkm::RangeId3& range)
 {
   return stream << "{ X:" << range.X << ", Y:" << range.Y << ", Z:" << range.Z << " }";
-}
+} // Declared inside of vtkm namespace so that the operator work with ADL lookup
+} // namespace vtkm
 
 #endif //vtk_m_RangeId3_h

vtkm/filter/ExtractStructured.h

@@ -116,7 +116,7 @@ public:
 
 private:
   vtkm::RangeId3 VOI;
-  vtkm::Id3 SampleRate;
+  vtkm::Id3 SampleRate = { 1, 1, 1 };
   bool IncludeBoundary;
   bool IncludeOffset;
   vtkm::worklet::ExtractStructured Worklet;

vtkm/worklet/ExtractStructured.h

@@ -69,59 +69,31 @@ private:
   bool IncludeBoundary;
 };
 
-template <vtkm::IdComponent Dimensions>
+struct ExtractCopy : public vtkm::worklet::WorkletMapField
-class LogicalToFlatIndex;
-
-template <>
-class LogicalToFlatIndex<1>
 {
-public:
+  using ControlSignature = void(FieldIn, FieldOut, WholeArrayIn);
-  LogicalToFlatIndex() = default;
 
-  explicit LogicalToFlatIndex(const vtkm::Id3&) {}
+  ExtractCopy(const vtkm::Id3& dim)
-
-  VTKM_EXEC_CONT
-  vtkm::Id operator()(const vtkm::Id3& index) const { return index[0]; }
-};
-
-template <>
-class LogicalToFlatIndex<2>
-{
-public:
-  LogicalToFlatIndex() = default;
-
-  explicit LogicalToFlatIndex(const vtkm::Id3& dim)
-    : XDim(dim[0])
-  {
-  }
-
-  VTKM_EXEC_CONT
-  vtkm::Id operator()(const vtkm::Id3& index) const { return index[0] + index[1] * this->XDim; }
-
-private:
-  vtkm::Id XDim;
-};
-
-template <>
-class LogicalToFlatIndex<3>
-{
-public:
-  LogicalToFlatIndex() = default;
-
-  explicit LogicalToFlatIndex(const vtkm::Id3& dim)
     : XDim(dim[0])
     , XYDim(dim[0] * dim[1])
   {
   }
-
   VTKM_EXEC_CONT
-  vtkm::Id operator()(const vtkm::Id3& index) const
+  inline vtkm::Id ToFlat(const vtkm::Id3& index) const
   {
     return index[0] + index[1] * this->XDim + index[2] * this->XYDim;
   }
 
-private:
+  template <typename ScalarType, typename WholeFieldIn>
-  vtkm::Id XDim, XYDim;
+  VTKM_EXEC void operator()(vtkm::Id3& index,
+                            ScalarType& output,
+                            const WholeFieldIn& inputField) const
+  {
+    output = inputField.Get(this->ToFlat(index));
+  }
+
+  vtkm::Id XDim;
+  vtkm::Id XYDim;
 };
 }
 } // extractstructured::internal
@@ -144,7 +116,7 @@ private:
                                                                  AxisIndexArrayCells,
                                                                  AxisIndexArrayCells>;
 
-  static AxisIndexArrayPoints MakeAxisIndexArrayPoints(vtkm::Id count,
+  inline AxisIndexArrayPoints MakeAxisIndexArrayPoints(vtkm::Id count,
                                                        vtkm::Id first,
                                                        vtkm::Id last,
                                                        vtkm::Id stride,
@@ -155,82 +127,56 @@ private:
     return vtkm::cont::make_ArrayHandleImplicit(fnctr, count);
   }
 
-  static AxisIndexArrayCells MakeAxisIndexArrayCells(vtkm::Id count,
+  inline AxisIndexArrayCells MakeAxisIndexArrayCells(vtkm::Id count,
                                                      vtkm::Id start,
                                                      vtkm::Id stride)
   {
     return vtkm::cont::make_ArrayHandleCounting(start, stride, count);
   }
 
-  static DynamicCellSetStructured MakeCellSetStructured(const vtkm::Id3& dimensions,
+  DynamicCellSetStructured MakeCellSetStructured(const vtkm::Id3& inputPointDims,
-                                                        const vtkm::Id3 offset)
+                                                 const vtkm::Id3& inputOffsets,
+                                                 vtkm::IdComponent forcedDimensionality = 0)
   {
-    int dimensionality = 0;
+    // when the point dimension for a given axis is 1 we
-    vtkm::Id xyz[3];
+    // need to lower the dimensonality by 1. So a Plane
-    for (int i = 0; i < 3; ++i)
+    // in XZ space would have a dimensonality of 2.
+    // likewise the global offsets need to also
+    // be updated when this occurs
+    vtkm::IdComponent dimensionality = forcedDimensionality;
+    vtkm::Id3 dimensions = inputPointDims;
+    vtkm::Id3 offset = inputOffsets;
+    for (int i = 0; i < 3 && (forcedDimensionality == 0); ++i)
     {
-      if (dimensions[i] > 1)
+      if (inputPointDims[i] > 1)
       {
-        xyz[dimensionality++] = dimensions[i];
+        dimensions[dimensionality] = inputPointDims[i];
+        offset[dimensionality] = inputOffsets[i];
+        ++dimensionality;
       }
     }
+
     switch (dimensionality)
     {
       case 1:
       {
         vtkm::cont::CellSetStructured<1> outCs;
-        outCs.SetPointDimensions(xyz[0]);
+        outCs.SetPointDimensions(dimensions[0]);
         outCs.SetGlobalPointIndexStart(offset[0]);
         return outCs;
       }
       case 2:
       {
         vtkm::cont::CellSetStructured<2> outCs;
-        outCs.SetPointDimensions(vtkm::Id2(xyz[0], xyz[1]));
+        outCs.SetPointDimensions(vtkm::Id2(dimensions[0], dimensions[1]));
         outCs.SetGlobalPointIndexStart(vtkm::Id2(offset[0], offset[1]));
         return outCs;
       }
       case 3:
       {
         vtkm::cont::CellSetStructured<3> outCs;
-        outCs.SetPointDimensions(vtkm::Id3(xyz[0], xyz[1], xyz[2]));
+        outCs.SetPointDimensions(dimensions);
-        outCs.SetGlobalPointIndexStart(vtkm::Id3(offset[0], offset[1], offset[2]));
+        outCs.SetGlobalPointIndexStart(offset);
-        return outCs;
-      }
-      default:
-        return DynamicCellSetStructured();
-    }
-  }
-
-  static DynamicCellSetStructured MakeCellSetStructured(const vtkm::Id3& dimensions)
-  {
-    int dimensionality = 0;
-    vtkm::Id xyz[3];
-    for (int i = 0; i < 3; ++i)
-    {
-      if (dimensions[i] > 1)
-      {
-        xyz[dimensionality++] = dimensions[i];
-      }
-    }
-    switch (dimensionality)
-    {
-      case 1:
-      {
-        vtkm::cont::CellSetStructured<1> outCs;
-        outCs.SetPointDimensions(xyz[0]);
-        return outCs;
-      }
-      case 2:
-      {
-        vtkm::cont::CellSetStructured<2> outCs;
-        outCs.SetPointDimensions(vtkm::Id2(xyz[0], xyz[1]));
-        return outCs;
-      }
-      case 3:
-      {
-        vtkm::cont::CellSetStructured<3> outCs;
-        outCs.SetPointDimensions(vtkm::Id3(xyz[0], xyz[1], xyz[2]));
         return outCs;
       }
       default:
@@ -239,172 +185,126 @@ private:
   }
 
 public:
-  template <vtkm::IdComponent Dimensionality>
+  inline DynamicCellSetStructured Run(const vtkm::cont::CellSetStructured<1>& cellset,
-  DynamicCellSetStructured Run(const vtkm::cont::CellSetStructured<Dimensionality>& cellset,
+                                      const vtkm::RangeId3& voi,
-                               const vtkm::RangeId3& voi,
+                                      const vtkm::Id3& sampleRate,
-                               const vtkm::Id3& sampleRate,
+                                      bool includeBoundary,
-                               bool includeBoundary,
+                                      bool includeOffset)
-                               bool includeOffset)
+  {
+    vtkm::Id pdims = cellset.GetPointDimensions();
+    vtkm::Id offsets = cellset.GetGlobalPointIndexStart();
+    return this->Compute(1,
+                         vtkm::Id3{ pdims, 1, 1 },
+                         vtkm::Id3{ offsets, 0, 0 },
+                         voi,
+                         sampleRate,
+                         includeBoundary,
+                         includeOffset);
+  }
+
+  inline DynamicCellSetStructured Run(const vtkm::cont::CellSetStructured<2>& cellset,
+                                      const vtkm::RangeId3& voi,
+                                      const vtkm::Id3& sampleRate,
+                                      bool includeBoundary,
+                                      bool includeOffset)
+  {
+    vtkm::Id2 pdims = cellset.GetPointDimensions();
+    vtkm::Id2 offsets = cellset.GetGlobalPointIndexStart();
+    return this->Compute(2,
+                         vtkm::Id3{ pdims[0], pdims[1], 1 },
+                         vtkm::Id3{ offsets[0], offsets[1], 0 },
+                         voi,
+                         sampleRate,
+                         includeBoundary,
+                         includeOffset);
+  }
+
+  inline DynamicCellSetStructured Run(const vtkm::cont::CellSetStructured<3>& cellset,
+                                      const vtkm::RangeId3& voi,
+                                      const vtkm::Id3& sampleRate,
+                                      bool includeBoundary,
+                                      bool includeOffset)
+  {
+    vtkm::Id3 pdims = cellset.GetPointDimensions();
+    vtkm::Id3 offsets = cellset.GetGlobalPointIndexStart();
+    return this->Compute(3, pdims, offsets, voi, sampleRate, includeBoundary, includeOffset);
+  }
+
+  DynamicCellSetStructured Compute(const int dimensionality,
+                                   const vtkm::Id3& ptdim,
+                                   const vtkm::Id3& offsets,
+                                   const vtkm::RangeId3& voi,
+                                   const vtkm::Id3& sampleRate,
+                                   bool includeBoundary,
+                                   bool includeOffset)
   {
     // Verify input parameters
-    vtkm::Vec<vtkm::Id, Dimensionality> ptdim(cellset.GetPointDimensions());
     vtkm::Id3 offset_vec(0, 0, 0);
     vtkm::Id3 globalOffset(0, 0, 0);
 
-    switch (Dimensionality)
+    this->InputDimensions = ptdim;
-    {
+    this->InputDimensionality = dimensionality;
-      case 1:
+    this->SampleRate = sampleRate;
-      {
-        if (sampleRate[0] < 1)
-        {
-          throw vtkm::cont::ErrorBadValue("Bad sampling rate");
-        }
-        break;
-      }
-      case 2:
-      {
-        if (sampleRate[0] < 1 || sampleRate[1] < 1)
-        {
-          throw vtkm::cont::ErrorBadValue("Bad sampling rate");
-        }
-        this->SampleRate = vtkm::Id3(sampleRate[0], sampleRate[1], 1);
-        this->InputDimensions = vtkm::Id3(ptdim[0], ptdim[1], 1);
-        break;
-      }
-      case 3:
-      {
-        if (sampleRate[0] < 1 || sampleRate[1] < 1 || sampleRate[2] < 1)
-        {
-          throw vtkm::cont::ErrorBadValue("Bad sampling rate");
-        }
-        this->SampleRate = sampleRate;
-        this->InputDimensions = vtkm::Id3(ptdim[0], ptdim[1], ptdim[2]);
-        break;
-      }
-      default:
-        VTKM_ASSERT(false && "Unsupported number of dimensions");
-    }
-    this->InputDimensionality = Dimensionality;
 
+    if (sampleRate[0] < 1 || sampleRate[1] < 1 || sampleRate[2] < 1)
+    {
+      throw vtkm::cont::ErrorBadValue("Bad sampling rate");
+    }
     if (includeOffset)
     {
-      vtkm::Id3 tmpDims(0, 0, 0);
+      vtkm::Id3 tmpDims = ptdim;
-      vtkm::Vec<vtkm::Id, Dimensionality> tmpOffset_vec = cellset.GetGlobalPointIndexStart();
+      offset_vec = offsets;
-      for (int i = 0; i < Dimensionality; ++i)
+      for (int i = 0; i < dimensionality; ++i)
       {
-        tmpDims[i] = ptdim[i];
+        if (dimensionality > i)
-        offset_vec[i] = tmpOffset_vec[i];
-      }
-      if (offset_vec[0] >= voi.X.Min)
-      {
-        globalOffset[0] = offset_vec[0];
-        this->VOI.X.Min = offset_vec[0];
-        if (globalOffset[0] + ptdim[0] < voi.X.Max)
         {
-          // Start from our GPIS (start point) up to the length of the
+          if (offset_vec[i] >= voi[i].Min)
-          // dimensions (if that is within VOI)
-          this->VOI.X.Max = globalOffset[0] + ptdim[0];
-        }
-        else
-        {
-          // If it isn't within the voi we set our dimensions from the
-          // GPIS up to the VOI.
-          tmpDims[0] = voi.X.Max - globalOffset[0];
-        }
-      }
-      else if (offset_vec[0] < voi.X.Min)
-      {
-        if (offset_vec[0] + ptdim[0] < voi.X.Min)
-        {
-          // If we're out of bounds we set the dimensions to 0. This
-          // causes a return of DynamicCellSetStructured
-          tmpDims[0] = 0;
-        }
-        else
-        {
-          // If our GPIS is less than VOI min, but our dimensions
-          // include the VOI we go from the minimal value that we
-          // can up to how far has been specified.
-          globalOffset[0] = voi.X.Min;
-          this->VOI.X.Min = voi.X.Min;
-          if (globalOffset[0] + ptdim[0] < voi.X.Max)
           {
-            this->VOI.X.Max = globalOffset[0] + ptdim[0];
+            globalOffset[i] = offset_vec[i];
+            this->VOI[i].Min = offset_vec[i];
+            if (globalOffset[i] + ptdim[i] < voi[i].Max)
+            {
+              // Start from our GPIS (start point) up to the length of the
+              // dimensions (if that is within VOI)
+              this->VOI[i].Max = globalOffset[i] + ptdim[i];
+            }
+            else
+            {
+              // If it isn't within the voi we set our dimensions from the
+              // GPIS up to the VOI.
+              tmpDims[i] = voi[i].Max - globalOffset[i];
+            }
           }
-          else
+          else if (offset_vec[i] < voi[i].Min)
           {
-            tmpDims[0] = voi.X.Max - globalOffset[0];
+            if (offset_vec[i] + ptdim[i] < voi[i].Min)
-          }
+            {
-        }
+              // If we're out of bounds we set the dimensions to 0. This
-      }
+              // causes a return of DynamicCellSetStructured
-      if (Dimensionality >= 2 && offset_vec[1] > voi.Y.Min)
+              tmpDims[i] = 0;
-      {
+            }
-        globalOffset[1] = offset_vec[1];
+            else
-        this->VOI.Y.Min = offset_vec[1];
+            {
-        if (globalOffset[1] + ptdim[1] < voi.Y.Max)
+              // If our GPIS is less than VOI min, but our dimensions
-        {
+              // include the VOI we go from the minimal value that we
-          this->VOI.Y.Max = globalOffset[1] + ptdim[1];
+              // can up to how far has been specified.
-        }
+              globalOffset[i] = voi[i].Min;
-        else
+              this->VOI[i].Min = voi[i].Min;
-        {
+              if (globalOffset[i] + ptdim[i] < voi[i].Max)
-          tmpDims[1] = voi.Y.Max - globalOffset[1];
+              {
-        }
+                this->VOI[i].Max = globalOffset[i] + ptdim[i];
-      }
+              }
-      else if (Dimensionality >= 2 && offset_vec[1] < voi.Y.Min)
+              else
-      {
+              {
-        if (offset_vec[1] + ptdim[1] < voi.Y.Min)
+                tmpDims[i] = voi[i].Max - globalOffset[i];
-        {
+              }
-          tmpDims[1] = 0;
+            }
-        }
-        else
-        {
-          globalOffset[1] = voi.Y.Min;
-          this->VOI.Y.Min = voi.Y.Min;
-          if (globalOffset[1] + ptdim[1] < voi.Y.Max)
-          {
-            this->VOI.Y.Max = globalOffset[1] + ptdim[1];
-          }
-          else
-          {
-            tmpDims[1] = voi.Y.Max - globalOffset[1];
-          }
-        }
-      }
-      if (Dimensionality == 3 && offset_vec[2] > voi.Z.Min)
-      {
-        globalOffset[2] = offset_vec[2];
-        this->VOI.Z.Min = offset_vec[2];
-        if (globalOffset[2] + ptdim[2] < voi.Z.Max)
-        {
-          this->VOI.Z.Max = globalOffset[2] + ptdim[2];
-        }
-        else
-        {
-          tmpDims[2] = voi.Z.Max - globalOffset[2];
-        }
-      }
-      else if (Dimensionality == 3 && offset_vec[2] < voi.Z.Min)
-      {
-        if (offset_vec[2] + ptdim[2] < voi.Z.Min)
-        {
-          tmpDims[2] = 0;
-        }
-        else
-        {
-          globalOffset[2] = voi.Z.Min;
-          this->VOI.Z.Min = voi.Z.Min;
-          if (globalOffset[2] + ptdim[2] < voi.Z.Max)
-          {
-            this->VOI.Z.Max = globalOffset[2] + ptdim[2];
-          }
-          else
-          {
-            tmpDims[2] = voi.Z.Max - globalOffset[2];
           }
         }
       }
       this->OutputDimensions = vtkm::Id3(tmpDims[0], tmpDims[1], tmpDims[2]);
     }
+
     this->VOI.X.Min = vtkm::Max(vtkm::Id(0), voi.X.Min);
     this->VOI.X.Max = vtkm::Min(this->InputDimensions[0] + globalOffset[0], voi.X.Max);
     this->VOI.Y.Min = vtkm::Max(vtkm::Id(0), voi.Y.Min);
@@ -414,39 +314,15 @@ public:
 
     if (!this->VOI.IsNonEmpty())
     {
-      vtkm::Id xyz[3] = { 0, 0, 0 };
+      vtkm::Id3 empty = { 0, 0, 0 };
-      switch (Dimensionality)
+      return MakeCellSetStructured(empty, empty, dimensionality);
-      {
-        case 1:
-        {
-          vtkm::cont::CellSetStructured<1> outCs;
-          outCs.SetPointDimensions(xyz[0]);
-          return outCs;
-        }
-        case 2:
-        {
-          vtkm::cont::CellSetStructured<2> outCs;
-          outCs.SetPointDimensions(vtkm::Id2(xyz[0], xyz[1]));
-          return outCs;
-        }
-        case 3:
-        {
-          vtkm::cont::CellSetStructured<3> outCs;
-          outCs.SetPointDimensions(vtkm::Id3(xyz[0], xyz[1], xyz[2]));
-          return outCs;
-        }
-        default:
-        {
-          return DynamicCellSetStructured();
-        }
-      }
     }
     if (!includeOffset)
     {
       // compute output dimensions
-      this->OutputDimensions = vtkm::Id3(1);
+      this->OutputDimensions = vtkm::Id3(1, 1, 1);
       vtkm::Id3 voiDims = this->VOI.Dimensions();
-      for (int i = 0; i < Dimensionality; ++i)
+      for (int i = 0; i < dimensionality; ++i)
       {
         this->OutputDimensions[i] = ((voiDims[i] + this->SampleRate[i] - 1) / this->SampleRate[i]) +
           ((includeBoundary && ((voiDims[i] - 1) % this->SampleRate[i])) ? 1 : 0);
@@ -480,11 +356,7 @@ public:
                                 this->SampleRate[2]));
     }
 
-    if (includeOffset)
+    return MakeCellSetStructured(this->OutputDimensions, globalOffset);
-    {
-      return MakeCellSetStructured(this->OutputDimensions, globalOffset);
-    }
-    return MakeCellSetStructured(this->OutputDimensions);
   }
 
 
@@ -507,8 +379,8 @@ private:
     {
     }
 
-    template <vtkm::IdComponent Dimensionality>
+    template <int N>
-    void operator()(const vtkm::cont::CellSetStructured<Dimensionality>& cellset) const
+    void operator()(const vtkm::cont::CellSetStructured<N>& cellset) const
     {
       *this->Output = this->Worklet->Run(
         cellset, *this->VOI, *this->SampleRate, this->IncludeBoundary, this->IncludeOffset);
@@ -630,50 +502,18 @@ public:
     }
   }
 
-private:
-  template <vtkm::IdComponent Dimensionality, typename T, typename Storage>
-  void MapPointField(const vtkm::cont::ArrayHandle<T, Storage>& in,
-                     vtkm::cont::ArrayHandle<T>& out) const
-  {
-    using namespace extractstructured::internal;
-
-    auto validPointsFlat = vtkm::cont::make_ArrayHandleTransform(
-      this->ValidPoints, LogicalToFlatIndex<Dimensionality>(this->InputDimensions));
-    vtkm::cont::ArrayCopy(make_ArrayHandlePermutation(validPointsFlat, in), out);
-  }
-
-  template <vtkm::IdComponent Dimensionality, typename T, typename Storage>
-  void MapCellField(const vtkm::cont::ArrayHandle<T, Storage>& in,
-                    vtkm::cont::ArrayHandle<T>& out) const
-  {
-    using namespace extractstructured::internal;
-
-    auto inputCellDimensions = this->InputDimensions - vtkm::Id3(1);
-    auto validCellsFlat = vtkm::cont::make_ArrayHandleTransform(
-      this->ValidCells, LogicalToFlatIndex<Dimensionality>(inputCellDimensions));
-    vtkm::cont::ArrayCopy(make_ArrayHandlePermutation(validCellsFlat, in), out);
-  }
-
 public:
   template <typename T, typename Storage>
   vtkm::cont::ArrayHandle<T> ProcessPointField(
     const vtkm::cont::ArrayHandle<T, Storage>& field) const
   {
+    using namespace extractstructured::internal;
     vtkm::cont::ArrayHandle<T> result;
-    switch (this->InputDimensionality)
+    result.Allocate(this->ValidPoints.GetNumberOfValues());
-    {
+
-      case 1:
+    ExtractCopy worklet(this->InputDimensions);
-        this->MapPointField<1>(field, result);
+    DispatcherMapField<ExtractCopy> dispatcher(worklet);
-        break;
+    dispatcher.Invoke(this->ValidPoints, result, field);
-      case 2:
-        this->MapPointField<2>(field, result);
-        break;
-      case 3:
-        this->MapPointField<3>(field, result);
-        break;
-      default:
-        break;
-    }
 
     return result;
   }
@@ -682,28 +522,21 @@ public:
   vtkm::cont::ArrayHandle<T> ProcessCellField(
     const vtkm::cont::ArrayHandle<T, Storage>& field) const
   {
+    using namespace extractstructured::internal;
     vtkm::cont::ArrayHandle<T> result;
-    switch (this->InputDimensionality)
+    result.Allocate(this->ValidCells.GetNumberOfValues());
-    {
+
-      case 1:
+    auto inputCellDimensions = this->InputDimensions - vtkm::Id3(1);
-        this->MapCellField<1>(field, result);
+    ExtractCopy worklet(inputCellDimensions);
-        break;
+    DispatcherMapField<ExtractCopy> dispatcher(worklet);
-      case 2:
+    dispatcher.Invoke(this->ValidCells, result, field);
-        this->MapCellField<2>(field, result);
-        break;
-      case 3:
-        this->MapCellField<3>(field, result);
-        break;
-      default:
-        break;
-    }
 
     return result;
   }
 
 private:
   vtkm::RangeId3 VOI;
-  vtkm::Id3 SampleRate;
+  vtkm::Id3 SampleRate = { 1, 1, 1 };
 
   int InputDimensionality;
   vtkm::Id3 InputDimensions;