
#include <fft2dmpi_with_fftwmpi2d.h>

FFT2DMPIWithFFTWMPI2D::FFT2DMPIWithFFTWMPI2D(int argN0, int argN1):
  BaseFFT2DMPI::BaseFFT2DMPI(argN0, argN1)
{
  int nK0_loc_iszero = 0;
  int count_nK0loc_zero = 0;
  struct timeval start_time, end_time;
  myreal total_usecs;
  ptrdiff_t local_nX0;
  ptrdiff_t local_nK0;

  this->_init();
#ifdef SINGLE_PREC
  fftwf_mpi_init();

  /* get local data size and allocate */
  alloc_local = fftwf_mpi_local_size_2d_transposed(N0, N1/2+1, MPI_COMM_WORLD,
                                                   &local_nX0, &local_X0_start,
                                                   &local_nK0, &local_K0_start);
#else
  fftw_mpi_init();

  /* get local data size and allocate */
  alloc_local = fftw_mpi_local_size_2d_transposed(N0, N1/2+1, MPI_COMM_WORLD,
                                                  &local_nX0, &local_X0_start,
                                                  &local_nK0, &local_K0_start);
#endif
  /* y corresponds to dim 0 in physical space */
  /* x corresponds to dim 1 in physical space */
  ny = N0;
  nx = N1;

  nX0 = N0;
  nX1 = N1;
  nX0loc = local_nX0;
  nXyloc = nX0loc;
  nX1_pad = 2*(N1/2 + 1);

  nKx = nx/2+1;
  nKxloc = local_nK0;
  nKy = ny;

  /* This 2D fft is transposed */
  is_transposed = 1;
  nK0 = nKx;
  nK0loc = nKxloc;
  nK1 = nKy;

  size_fieldK = nKxloc * nKy;

  /* Case nK0loc ==0 */
  if (nK0loc == 0)
  {
      nK0_loc_iszero = 1;
  }
  MPI_Allreduce(&nK0_loc_iszero, &count_nK0loc_zero, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
  last_rank_nozero = nb_proc - 1 - count_nK0loc_zero;

  flags = FFTW_MEASURE;
/*    flags = FFTW_ESTIMATE;*/
/*    flags = FFTW_PATIENT;*/

#ifdef SINGLE_PREC
  arrayX = fftwf_alloc_real(2 * alloc_local);
  arrayK = fftwf_alloc_complex(alloc_local);

  gettimeofday(&start_time, NULL);

  plan_r2c = fftwf_mpi_plan_dft_r2c_2d(
      N0, N1, arrayX,
      arrayK, MPI_COMM_WORLD,
      flags|FFTW_MPI_TRANSPOSED_OUT);

  plan_c2r = fftwf_mpi_plan_dft_c2r_2d(
      N0, N1,
      arrayK, arrayX,
      MPI_COMM_WORLD,
      flags|FFTW_MPI_TRANSPOSED_IN);
#else
  arrayX = fftw_alloc_real(2 * alloc_local);
  arrayK = reinterpret_cast<mycomplex*>(fftw_alloc_complex(alloc_local));

  gettimeofday(&start_time, NULL);

  plan_r2c = fftw_mpi_plan_dft_r2c_2d(
      N0, N1, arrayX,
      reinterpret_cast<mycomplex_fftw*>(arrayK), MPI_COMM_WORLD,
      flags|FFTW_MPI_TRANSPOSED_OUT);

  plan_c2r = fftw_mpi_plan_dft_c2r_2d(
      N0, N1,
      reinterpret_cast<mycomplex_fftw*>(arrayK), arrayX,
      MPI_COMM_WORLD,
      flags|FFTW_MPI_TRANSPOSED_IN);
#endif
  gettimeofday(&end_time, NULL);

  total_usecs = (end_time.tv_sec-start_time.tv_sec) +
    (end_time.tv_usec-start_time.tv_usec)/1000000.;

  if (rank == 0)
    printf("Initialization (%s) done in %f s\n",
	   this->get_classname(), total_usecs);

}

void FFT2DMPIWithFFTWMPI2D::destroy(void)
{
  // cout << "Object is being destroyed" << endl;
#ifdef SINGLE_PREC
  fftwf_destroy_plan(plan_r2c);
  fftwf_destroy_plan(plan_c2r);
  fftwf_free(arrayX);
  fftwf_free(arrayK);
#else
  fftw_destroy_plan(plan_r2c);
  fftw_destroy_plan(plan_c2r);
  fftw_free(arrayX);
  fftw_free(arrayK);
#endif
}


FFT2DMPIWithFFTWMPI2D::~FFT2DMPIWithFFTWMPI2D(void)
{
}


bool FFT2DMPIWithFFTWMPI2D::are_parameters_bad()
{
  if (N0 % nb_proc != 0)
    {
      if (rank == 0)
	cout << "bad parameters: (N0 % nb_proc != 0)" << endl;
      return 1;
    }
  if (N1/2 % nb_proc != 0)
    {
      if (rank == 0)
	cout << "bad parameters: (N1/2 % nb_proc != 0)" << endl;
      return 1;
    }
  return 0;
}


char const* FFT2DMPIWithFFTWMPI2D::get_classname()
{ return "FFT2DMPIWithFFTWMPI2D";}


myreal FFT2DMPIWithFFTWMPI2D::compute_energy_from_X(myreal* fieldX)
{
  int i0, i1;
  myreal energy_loc = 0;
  myreal energy;

  for (i0=0; i0<nX0loc; i0++)
    for (i1=0; i1<nX1; i1++)
      energy_loc += pow(fieldX[i1 + i0*nX1], 2);
#ifdef SINGLE_PREC
  MPI_Allreduce(&energy_loc, &energy, 1, MPI_FLOAT, MPI_SUM, MPI_COMM_WORLD);
#else
  MPI_Allreduce(&energy_loc, &energy, 1, MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);
#endif
  return energy / 2 * inv_coef_norm;
}


myreal FFT2DMPIWithFFTWMPI2D::compute_energy_from_K(mycomplex* fieldK)
{
  int i0, i1, i_tmp;
  myreal energy_loc = 0;
  myreal energy_tmp = 0;
  myreal energy;

  if (nK0loc != 0)
  {
  // modes i0 = iKx = 0
  i0 = 0;
  for (i1=0; i1<nK1; i1++)
    energy_tmp += pow(abs(fieldK[i1]), 2);

  //if iKx == 0 | nK0loc == 1 && iKx=last
  if ((rank == 0) | ((rank == last_rank_nozero) & (nK0loc == 1)))  // i.e. if iKx == 0
    energy_loc = energy_tmp/2;
  else
    energy_loc = energy_tmp;

  if (nK0loc > 1)
  {
    // modes i0 = iKx = last = nK0loc - 1
    i0 = nK0loc - 1;
    energy_tmp = 0.;
    i_tmp = i0 * nK1;
    for (i1=0; i1<nK1; i1++)
      energy_tmp += pow(abs(fieldK[i1 + i_tmp]), 2);
    if (rank == last_rank_nozero)
      energy_loc += energy_tmp/2;
    else
      energy_loc += energy_tmp;
    // other modes
    for (i0=1; i0<nK0loc-1; i0++)
      for (i1=0; i1<nK1; i1++)
        energy_loc += pow(abs(fieldK[i1 + i0*nK1]), 2);
   }
   }
#ifdef SINGLE_PREC
  MPI_Allreduce(&energy_loc, &energy, 1, MPI_FLOAT, MPI_SUM, MPI_COMM_WORLD);
#else
  MPI_Allreduce(&energy_loc, &energy, 1, MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);
#endif
  return energy;
}


myreal FFT2DMPIWithFFTWMPI2D::sum_wavenumbers(myreal* fieldK)
{
  int i0, i1, i_tmp;
  myreal sum_loc = 0;
  myreal sum_tmp = 0;
  myreal sum_tot;

  // modes i0 = iKx = 0
  i0 = 0;
  for (i1=0; i1<nK1; i1++)
    sum_tmp += fieldK[i1];

  //if (local_K0_start == 0)  // i.e. if iKx == 0
  if ((rank == 0) | ((rank == last_rank_nozero) & (nK0loc == 1)))  // i.e. if iKx == 0
    sum_loc = sum_tmp/2;
  else
    sum_loc = sum_tmp;

  if (nK0loc > 1)
  {
    // modes i0 = iKx = last = nK0loc - 1
    i0 = nK0loc - 1;
    sum_tmp = 0.;
    i_tmp = i0 * nK1;
    for (i1=0; i1<nK1; i1++)
      sum_tmp += fieldK[i1 + i_tmp];

    if (rank == last_rank_nozero)
      sum_loc += sum_tmp/2;
    else
      sum_loc += sum_tmp;

    // other modes
    for (i0=1; i0<nK0loc-1; i0++)
      for (i1=0; i1<nK1; i1++)
        sum_loc += fieldK[i1 + i0*nK1];
  }
#ifdef SINGLE_PREC
  MPI_Allreduce(&sum_loc, &sum_tot, 1, MPI_FLOAT, MPI_SUM, MPI_COMM_WORLD);
#else
  MPI_Allreduce(&sum_loc, &sum_tot, 1, MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);
#endif
  return 2*sum_tot;
}


myreal FFT2DMPIWithFFTWMPI2D::compute_mean_from_X(myreal* fieldX)
{
  myreal mean, local_mean;
  int ii;
  local_mean=0.;

  for (ii=0; ii<nX0loc*nX1; ii++)
    local_mean += fieldX[ii];
#ifdef SINGLE_PREC
  MPI_Allreduce(&local_mean, &mean, 1, MPI_FLOAT, MPI_SUM, MPI_COMM_WORLD);
#else
  MPI_Allreduce(&local_mean, &mean, 1, MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);
#endif
  return mean * inv_coef_norm;
}


myreal FFT2DMPIWithFFTWMPI2D::compute_mean_from_K(mycomplex* fieldK)
{
  myreal mean, local_mean;
  if (local_K0_start == 0)
    local_mean = real(fieldK[0]);
  else
    local_mean = 0.;
#ifdef SINGLE_PREC
  MPI_Allreduce(&local_mean, &mean, 1, MPI_FLOAT, MPI_SUM, MPI_COMM_WORLD);
#else
  MPI_Allreduce(&local_mean, &mean, 1, MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);
#endif
  return mean;
}


void FFT2DMPIWithFFTWMPI2D::fft(myreal *fieldX, mycomplex *fieldK)
{
  int i0, i1;
  // cout << "FFT2DMPIWithFFTWMPI2D::fft" << endl;

  for (i0=0; i0<nX0loc; i0++)
    for (i1=0; i1<nX1; i1++)
      arrayX[i1 + i0*nX1_pad] = fieldX[i1 + i0*nX1];

#ifdef SINGLE_PREC
  fftwf_execute(plan_r2c);
#else
  fftw_execute(plan_r2c);
#endif
  for (i0=0; i0<nK0loc; i0++)
    for (i1=0; i1<nK1; i1++)
      fieldK[i1 + i0*nK1]  = arrayK[i1 + i0*nK1] * inv_coef_norm;
}


void FFT2DMPIWithFFTWMPI2D::ifft(mycomplex *fieldK, myreal *fieldX)
{
  int i0, i1;
  // cout << "FFT2DMPIWithFFTWMPI2D::ifft" << endl;
  memcpy(arrayK, fieldK, size_fieldK * sizeof(mycomplex));
#ifdef SINGLE_PREC
  fftwf_execute(plan_c2r);
#else
  fftw_execute(plan_c2r);
#endif
  for (i0=0; i0<nX0loc; i0++)
    for (i1=0; i1<nX1; i1++)
      fieldX[i1 + i0*nX1] = arrayX[i1 + i0*nX1_pad];
}
