Add example to call FFTs from Host and Device

examples/05_1DFFT_HOST_DEVICE/05_1DFFT_HOST_DEVICE.cpp

@@ -0,0 +1,72 @@
+#include <Kokkos_Core.hpp>
+#include <Kokkos_Complex.hpp>
+#include <Kokkos_Random.hpp>
+#include <KokkosFFT.hpp>
+
+using execution_space = Kokkos::DefaultExecutionSpace;
+using host_execution_space = Kokkos::DefaultHostExecutionSpace;
+template <typename T> using View1D = Kokkos::View<T*, execution_space>;
+template <typename T> using HostView1D = Kokkos::View<T*, host_execution_space>;
+
+int main( int argc, char* argv[] ) {
+  Kokkos::initialize( argc, argv );
+  {
+    constexpr int n0 = 128;
+    const Kokkos::complex<double> I(1.0, 1.0);
+
+    // 1D C2C FFT (Forward and Backward)
+    View1D<Kokkos::complex<double> > xc2c("xc2c", n0);
+    View1D<Kokkos::complex<double> > xc2c_hat("xc2c_hat", n0);
+    View1D<Kokkos::complex<double> > xc2c_inv("xc2c_inv", n0);
+
+    Kokkos::Random_XorShift64_Pool<> random_pool(12345);
+    Kokkos::fill_random(xc2c, random_pool, I);
+
+    KokkosFFT::fft(execution_space(), xc2c, xc2c_hat);
+    KokkosFFT::ifft(execution_space(), xc2c_hat, xc2c_inv);
+
+    // 1D R2C FFT
+    View1D<double> xr2c("xr2c", n0);
+    View1D<Kokkos::complex<double> > xr2c_hat("xr2c_hat", n0/2+1);
+    Kokkos::fill_random(xr2c, random_pool, 1);
+
+    KokkosFFT::rfft(execution_space(), xr2c, xr2c_hat);
+
+    // 1D C2R FFT
+    View1D<Kokkos::complex<double> > xc2r("xr2c_hat", n0/2+1);
+    View1D<double> xc2r_hat("xc2r", n0);
+    Kokkos::fill_random(xc2r, random_pool, I);
+
+    KokkosFFT::irfft(execution_space(), xc2r, xc2r_hat);
+
+    #ifdef ENABLE_HOST_AND_DEVICE
+      // FFTs on Host
+      // 1D C2C FFT (Forward and Backward)
+      HostView1D<Kokkos::complex<double> > h_xc2c("h_xc2c", n0);
+      HostView1D<Kokkos::complex<double> > h_xc2c_hat("h_xc2c_hat", n0);
+      HostView1D<Kokkos::complex<double> > h_xc2c_inv("h_xc2c_inv", n0);
+
+      Kokkos::deep_copy(h_xc2c, xc2c);
+
+      KokkosFFT::fft(host_execution_space(), h_xc2c, h_xc2c_hat);
+      KokkosFFT::ifft(host_execution_space(), h_xc2c_hat, h_xc2c_inv);
+
+      // 1D R2C FFT
+      HostView1D<double> h_xr2c("h_xr2c", n0);
+      HostView1D<Kokkos::complex<double> > h_xr2c_hat("h_xr2c_hat", n0/2+1);
+
+      Kokkos::deep_copy(h_xr2c, xr2c);
+      KokkosFFT::rfft(host_execution_space(), h_xr2c, h_xr2c_hat);
+
+      // 1D C2R FFT
+      HostView1D<Kokkos::complex<double> > h_xc2r("h_xr2c_hat", n0/2+1);
+      HostView1D<double> h_xc2r_hat("h_xc2r", n0);
+
+      Kokkos::deep_copy(h_xc2r, xc2r);
+      KokkosFFT::irfft(host_execution_space(), h_xc2r, h_xc2r_hat);
+    #endif
+  }
+  Kokkos::finalize();
+
+  return 0;
+}

examples/05_1DFFT_HOST_DEVICE/CMakeLists.txt

@@ -0,0 +1,2 @@
+add_executable(05_1DFFT_HOST_DEVICE 05_1DFFT_HOST_DEVICE.cpp)
+target_link_libraries(05_1DFFT_HOST_DEVICE PUBLIC Kokkos::fft)

examples/05_1DFFT_HOST_DEVICE/numpy_1DFFT.py

@@ -0,0 +1,17 @@
+import numpy as np
+
+if __name__ == '__main__':
+    n0 = 128
+
+    # 1D C2C FFT (Forward and Backward)
+    xc2c = np.random.rand(n0) + 1j * np.random.rand(n0)
+    xc2c_hat = np.fft.fft(xc2c)
+    xc2c_inv = np.fft.ifft(xc2c_hat)
+
+    # 1D R2C FFT
+    xr2c = np.random.rand(n0)
+    xr2c_hat = np.fft.rfft(xr2c)
+
+    # 1D C2R FFT
+    xc2r = np.random.rand(n0//2+1)
+    xc2r_hat = np.fft.irfft(xc2r)

examples/CMakeLists.txt

@@ -1,4 +1,7 @@
 add_subdirectory(01_1DFFT)
 add_subdirectory(02_2DFFT)
 add_subdirectory(03_NDFFT)
-add_subdirectory(04_batchedFFT)
+add_subdirectory(04_batchedFFT)
+if(KokkosFFT_ENABLE_HOST_AND_DEVICE)
+  add_subdirectory(05_1DFFT_HOST_DEVICE)
+endif()