FFT buffer base class template (idaholab#401)

include/userobjects/FFTBufferBase.h

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+/**********************************************************************/
+/*                     DO NOT MODIFY THIS HEADER                      */
+/* MAGPIE - Mesoscale Atomistic Glue Program for Integrated Execution */
+/*                                                                    */
+/*            Copyright 2017 Battelle Energy Alliance, LLC            */
+/*                        ALL RIGHTS RESERVED                         */
+/**********************************************************************/
+
+#pragma once
+
+#include "GeneralUserObject.h"
+
+template <typename T>
+class FFTBufferBase;
+
+/**
+ * Generic FFT interleaved data buffer base class
+ */
+template <typename T>
+class FFTBufferBase : public GeneralUserObject
+{
+public:
+  static InputParameters validParams();
+
+  FFTBufferBase(const InputParameters & parameters);
+
+  virtual void initialize() {}
+  virtual void execute() {}
+  virtual void finalize() {}
+
+  // transforms
+  virtual void forward() = 0;
+  virtual void backward() = 0;
+
+  // data access
+  const T & operator[](std::size_t i) const { return _buffer[i]; }
+  T & operator[](std::size_t i) { return _buffer[i]; }
+
+protected:
+  /// get the addres of the first data element of the ith object in the bufefr
+  Real * start(std::size_t i);
+
+  /// get the number of transforms required for type T
+  std::size_t howMany() const;
+
+  ///@{ mesh data
+  MooseMesh & _mesh;
+  unsigned int _dim;
+  ///@}
+
+  /// grid size for FFT (needs to be signed for FFTW)
+  std::vector<int> _grid;
+
+  ///@{ simulation box extents
+  Point _min_corner;
+  Point _max_corner;
+  Point _box_size;
+  ///@}
+
+  /// FFT grid cell volume
+  Real _cell_volume;
+
+  ///@{ FFT data buffer
+  std::vector<T> _buffer;
+  std::size_t _buffer_size;
+  ///@}
+
+  /// pointer to the start of the data
+  Real * _start;
+
+  /// stride in units of double size
+  std::ptrdiff_t _stride;
+};

include/userobjects/FFTWBufferBase.h

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+/**********************************************************************/
+/*                     DO NOT MODIFY THIS HEADER                      */
+/* MAGPIE - Mesoscale Atomistic Glue Program for Integrated Execution */
+/*                                                                    */
+/*            Copyright 2017 Battelle Energy Alliance, LLC            */
+/*                        ALL RIGHTS RESERVED                         */
+/**********************************************************************/
+#ifdef FFTW3_ENABLED
+
+#pragma once
+
+#include "FFTBufferBase.h"
+
+#include "fftw3.h"
+
+template <typename T>
+class FFTWBufferBase;
+
+/**
+ * FFTW specific interleaved data buffer base class
+ */
+template <typename T>
+class FFTWBufferBase : public FFTBufferBase<T>
+{
+public:
+  FFTWBufferBase(const InputParameters & parameters);
+  ~FFTWBufferBase();
+
+  // transforms
+  void forward() override;
+  void backward() override;
+
+protected:
+  /// FFTW plans
+  fftw_plan _forward_plan;
+  fftw_plan _backward_plan;
+};
+
+#endif

src/userobjects/FFTBufferBase.C

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+/**********************************************************************/
+/*                     DO NOT MODIFY THIS HEADER                      */
+/* MAGPIE - Mesoscale Atomistic Glue Program for Integrated Execution */
+/*                                                                    */
+/*            Copyright 2017 Battelle Energy Alliance, LLC            */
+/*                        ALL RIGHTS RESERVED                         */
+/**********************************************************************/
+#include "FFTBufferBase.h"
+#include "MooseTypes.h"
+#include "MyTRIMMesh.h"
+#include "RankTwoTensor.h"
+#include "RankThreeTensor.h"
+#include "RankFourTensor.h"
+
+#include <type_traits>
+
+// template <>
+// InputParameters
+// validParams<FFTBufferBase>()
+// {
+//   InputParameters params = validParams<GeneralUserObject>();
+//   params.addClassDescription("");
+//   return params;
+// }
+
+template <typename T>
+InputParameters
+FFTBufferBase<T>::validParams()
+{
+  InputParameters params = GeneralUserObject::validParams();
+  params.addClassDescription("Fourier transform data buffer object.");
+  params.addRangeCheckedParam<std::vector<int>>(
+      "grid",
+      "grid > 0",
+      "Number of grid cells in each dimension to compute "
+      "the FFT on (can be omitted when using MyTRIMMesh)");
+  params.addParam<unsigned int>(
+      "max_h_level", 0, "Further grid refinement to apply when using MyTRIMMesh with adaptivity");
+  return params;
+}
+
+template <typename T>
+FFTBufferBase<T>::FFTBufferBase(const InputParameters & parameters)
+  : GeneralUserObject(parameters),
+    _mesh(_subproblem.mesh()),
+    _dim(_mesh.dimension()),
+    _cell_volume(1.0),
+    _buffer_size(1)
+
+{
+  // make sure Real is double
+  static_assert(
+      std::is_same<Real, double>::value,
+      "Libmesh must be build with double precision floating point numbers as the 'Real' type.");
+
+  // FFT needs a regular grid of values to operate on
+  if (isParamValid("grid"))
+  {
+    // if valid use the user-supplied sampling grid
+    _grid = getParam<std::vector<int>>("grid");
+    if (_grid.size() != _dim)
+      paramError("grid", "Number of entries must match the mesh dimension ", _dim);
+  }
+  else
+  {
+    auto * mytrim_mesh = dynamic_cast<MyTRIMMesh *>(&_mesh);
+    if (!mytrim_mesh)
+      mooseError("Must specify 'grid' parameter if not using MyTRIMMesh");
+
+    // querying the mesh to set grid
+    for (unsigned int i = 0; i < _dim; ++i)
+      _grid.push_back(mytrim_mesh->getCellCountInDimension(i));
+  }
+
+  // refine grid by max_h_level powers of two
+  auto max_h_level = getParam<unsigned int>("max_h_level");
+  for (auto & count : _grid)
+    count = count << max_h_level;
+
+  // get mesh extents and calculate space required and estimate spectrum bins
+  for (unsigned int i = 0; i < _dim; ++i)
+  {
+    _min_corner(i) = _mesh.getMinInDimension(i);
+    _max_corner(i) = _mesh.getMaxInDimension(i);
+    _box_size(i) = _max_corner(i) - _min_corner(i);
+    _cell_volume *= _box_size(i) / _grid[i];
+
+    // last direction needs to be padded for in-place transforms
+    _buffer_size *= (i == _dim - 1) ? ((_grid[i] >> 1) + 1) << 1 : _grid[i];
+  }
+  _buffer.resize(_buffer_size);
+
+  // compute stride and start pointer
+  auto istart = start(0);
+  std::ptrdiff_t istride = reinterpret_cast<char *>(start(1)) - reinterpret_cast<char *>(istart);
+  if (istride % sizeof(Real) != 0)
+    mooseError("Invalid data alignment");
+  istride /= sizeof(Real);
+}
+
+template <>
+Real *
+FFTBufferBase<Real>::start(std::size_t i)
+{
+  return &_buffer[i];
+}
+
+template <>
+Real *
+FFTBufferBase<RealVectorValue>::start(std::size_t i)
+{
+  return &_buffer[i](0);
+}
+
+template <>
+Real *
+FFTBufferBase<RankTwoTensor>::start(std::size_t i)
+{
+  return &_buffer[i](0, 0);
+}
+
+template <>
+Real *
+FFTBufferBase<RankThreeTensor>::start(std::size_t i)
+{
+  return &_buffer[i](0, 0, 0);
+}
+
+template <>
+Real *
+FFTBufferBase<RankFourTensor>::start(std::size_t i)
+{
+  return &_buffer[i](0, 0, 0, 0);
+}
+
+template <>
+std::size_t
+FFTBufferBase<Real>::howMany() const
+{
+  return 1;
+}
+
+template <>
+std::size_t
+FFTBufferBase<RealVectorValue>::howMany() const
+{
+  return LIBMESH_DIM;
+}
+
+template <>
+std::size_t
+FFTBufferBase<RankTwoTensor>::howMany() const
+{
+  return LIBMESH_DIM * LIBMESH_DIM;
+}
+
+template <>
+std::size_t
+FFTBufferBase<RankThreeTensor>::howMany() const
+{
+  return LIBMESH_DIM * LIBMESH_DIM * LIBMESH_DIM;
+}
+
+template <>
+std::size_t
+FFTBufferBase<RankFourTensor>::howMany() const
+{
+  return LIBMESH_DIM * LIBMESH_DIM * LIBMESH_DIM * LIBMESH_DIM;
+}
+
+// explicit instantiation
+template class FFTBufferBase<Real>;
+template class FFTBufferBase<RealVectorValue>;
+template class FFTBufferBase<RankTwoTensor>;
+template class FFTBufferBase<RankThreeTensor>;
+template class FFTBufferBase<RankFourTensor>;

src/userobjects/FFTWBufferBase.C

@@ -0,0 +1,55 @@
+/**********************************************************************/
+/*                     DO NOT MODIFY THIS HEADER                      */
+/* MAGPIE - Mesoscale Atomistic Glue Program for Integrated Execution */
+/*                                                                    */
+/*            Copyright 2017 Battelle Energy Alliance, LLC            */
+/*                        ALL RIGHTS RESERVED                         */
+/**********************************************************************/
+#ifdef FFTW3_ENABLED
+
+#include "FFTWBufferBase.h"
+#include "MyTRIMMesh.h"
+#include "MooseTypes.h"
+#include "RankTwoTensor.h"
+#include "RankThreeTensor.h"
+#include "RankFourTensor.h"
+
+template <typename T>
+FFTWBufferBase<T>::FFTWBufferBase(const InputParameters & parameters)
+  : FFTBufferBase<T>(parameters), _forward_plan(nullptr), _backward_plan(nullptr)
+{
+  // create plans
+}
+
+template <typename T>
+FFTWBufferBase<T>::~FFTWBufferBase()
+{
+  // destroy FFTW plans
+  fftw_destroy_plan(_forward_plan);
+  fftw_destroy_plan(_backward_plan);
+}
+
+template <typename T>
+void
+FFTWBufferBase<T>::forward()
+{
+  // execute plan
+  fftw_execute(_forward_plan);
+}
+
+template <typename T>
+void
+FFTWBufferBase<T>::backward()
+{
+  // execute plan
+  fftw_execute(_backward_plan);
+}
+
+// explicit instantiation
+template class FFTWBufferBase<Real>;
+template class FFTWBufferBase<RealVectorValue>;
+template class FFTWBufferBase<RankTwoTensor>;
+template class FFTWBufferBase<RankThreeTensor>;
+template class FFTWBufferBase<RankFourTensor>;
+
+#endif