Introduce interface IFFT to FFT

Author: ahojukka5

include/openpfc/core/decomposition.hpp

@@ -53,6 +53,8 @@ using pfc::types::Real3;
 using World = pfc::world::World<CartesianTag>;
 using Int3 = pfc::types::Int3;
 
+using heffte::proc_setup_min_surface;
+
 /**
  * @brief Describes a static, pure partitioning of the global simulation domain
  * into local subdomains.
@@ -188,11 +190,11 @@ inline const auto create(const World &world, const Int3 &grid) noexcept {
 
 inline const auto create(const World &world, const int &nparts) noexcept {
   auto indices = to_indices(world);
-  auto grid = heffte::proc_setup_min_surface(indices, nparts);
+  auto grid = proc_setup_min_surface(indices, nparts);
   return create(world, grid);
 }
 
-inline const auto get_num_domains(const Decomposition &decomposition) noexcept {
+inline int get_num_domains(const Decomposition &decomposition) noexcept {
   return get_subworlds(decomposition).size();
 }
 

include/openpfc/core/world.hpp

@@ -295,7 +295,7 @@ template <typename T> int get_size(const World<T> &world, int index) {
  * @param w World object.
  * @return The total number of grid points.
  */
-template <typename T> int total_size(const World<T> &world) noexcept {
+template <typename T> size_t get_total_size(const World<T> &world) noexcept {
   return get_size(world, 0) * get_size(world, 1) * get_size(world, 2);
 }
 

include/openpfc/fft.hpp

@@ -27,10 +27,10 @@ using pfc::types::Int3;
  * real-to-complex symmetry, and the boxes for real and complex FFT data.
  */
 struct FFTLayout {
-  const Decomposition m_decomposition;       ///< The Decomposition object.
-  const int m_r2c_direction = 0;             ///< Real-to-complex symmetry direction.
-  const std::vector<box3di> m_real_boxes;    ///< Real boxes for FFT.
-  const std::vector<box3di> m_complex_boxes; ///< Complex boxes for FFT.
+  const Decomposition m_decomposition; ///< The Decomposition object.
+  const int m_r2c_direction = 0;       ///< Real-to-complex symmetry direction.
+  const std::vector<heffte::box3d<int>> m_real_boxes;    ///< Real boxes for FFT.
+  const std::vector<heffte::box3d<int>> m_complex_boxes; ///< Complex boxes for FFT.
 };
 
 /**
@@ -62,15 +62,43 @@ using pfc::types::Int3;
 using pfc::types::Real3;
 
 using Decomposition = pfc::decomposition::Decomposition;
+using RealVector = std::vector<double>;
 using ComplexVector = std::vector<std::complex<double>>;
 using fft_r2c = heffte::fft3d_r2c<heffte::backend::fftw>;
 using box3di = heffte::box3d<int>; ///< Type alias for 3D integer box.
 
+struct IFFT {
+  virtual ~IFFT() = default;
+
+  /**
+   * @brief Performs the forward FFT transformation.
+   *
+   * @param in Input vector of real values.
+   * @param out Output vector of complex values.
+   */
+  virtual void forward(const RealVector &in, ComplexVector &out) = 0;
+
+  /**
+   * @brief Performs the backward (inverse) FFT transformation.
+   *
+   * @param in Input vector of complex values.
+   * @param out Output vector of real values.
+   */
+  virtual void backward(const ComplexVector &in, RealVector &out) = 0;
+
+  virtual void reset_fft_time() = 0;
+  virtual double get_fft_time() const = 0;
+
+  virtual size_t size_inbox() const = 0;
+  virtual size_t size_outbox() const = 0;
+  virtual size_t size_workspace() const = 0;
+};
+
 /**
  * @brief FFT class for performing forward and backward Fast Fourier
  * Transformations.
  */
-struct FFT {
+struct FFT : IFFT {
 
   // const Decomposition m_decomposition; /**< The Decomposition object. */
   // const box3di m_inbox, m_outbox;      /**< Local inbox and outbox boxes. */

tests/CMakeLists.txt

@@ -10,6 +10,7 @@ add_executable(openpfc-tests
                test_world.cpp
                test_box3d.cpp
                test_decomposition.cpp
+               test_field.cpp
                test_fft.cpp
                test_fft_setting.cpp
                test_arraynd.cpp

tests/test_world.cpp

@@ -85,7 +85,7 @@ TEST_CASE("World - Total Size", "[world]") {
   SECTION("Correct total size calculation") {
     Int3 dimensions = {10, 20, 30};
     World world = world::create(dimensions);
-    REQUIRE(total_size(world) == 10 * 20 * 30);
+    REQUIRE(get_total_size(world) == 10 * 20 * 30);
   }
 }