text: // Copyright (c) 2019 - present Advanced Micro Devices, Inc. All rights
  // reserved.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  
  #include <complex>
  #include <iostream>
  #include <vector>
  
  #include <hip/hip_runtime.h>
  #include <hipfft/hipfft.h>
  
  int main()
  {
      std::cout << "hipfft 3D double-precision complex-to-complex transform\n";
  
      const int Nx        = 4;
      const int Ny        = 4;
      const int Nz        = 4;
      int       direction = HIPFFT_FORWARD; // forward=-1, backward=1
  
      std::vector<std::complex<double>> cdata(Nx * Ny * Nz);
      size_t complex_bytes = sizeof(decltype(cdata)::value_type) * cdata.size();
  
      // Create HIP device object and copy data to device:
      // hipfftComplex for single-precision
      hipError_t           rt;
      hipfftDoubleComplex* x;
      rt = hipMalloc(&x, complex_bytes);
      assert(rt == HIP_SUCCESS);
  
      // Inititalize the data
      std::vector<double> rdata(Nx * Ny * Nz);
      for(size_t i = 0; i < Nx * Ny * Nz; i++)
      {
          rdata[i] = i;
      }
  
      hipMemcpy(x, cdata.data(), complex_bytes, hipMemcpyHostToDevice);
      std::cout << "input:\n";
      for(int i = 0; i < Nx; i++)
      {
          for(int j = 0; j < Ny; j++)
          {
              for(int k = 0; k < Nz; k++)
              {
                  int pos = (i * Ny + j) * Nz + k;
                  std::cout << cdata[pos] << " ";
              }
              std::cout << "\n";
          }
          std::cout << "\n";
      }
      std::cout << std::endl;
  
      // Create plan
      hipfftResult rc   = HIPFFT_SUCCESS;
      hipfftHandle plan = NULL;
      rc                = hipfftCreate(&plan);
      assert(rc == HIPFFT_SUCCESS);
      rc = hipfftPlan3d(&plan, // plan handle
                        Nx, // transform length
                        Ny, // transform length
                        Nz, // transform length
                        HIPFFT_Z2Z); // transform type (HIPFFT_C2C for single-precision)
      assert(rc == HIPFFT_SUCCESS);
  
      // Execute plan
      // hipfftExecZ2Z: double precision, hipfftExecC2C: for single-precision
      rc = hipfftExecZ2Z(plan, x, x, direction);
      assert(rc == HIPFFT_SUCCESS);
  
      std::cout << "output:\n";
      hipMemcpy(cdata.data(), x, complex_bytes, hipMemcpyDeviceToHost);
      for(int i = 0; i < Nx; i++)
      {
          for(int j = 0; j < Ny; j++)
          {
              for(int k = 0; k < Nz; k++)
              {
                  int pos = (i * Ny + j) * Nz + k;
                  std::cout << cdata[pos] << " ";
              }
              std::cout << "\n";
          }
          std::cout << "\n";
      }
      std::cout << std::endl;
  
      hipfftDestroy(plan);
      hipFree(x);
  
      return 0;
  }
  