/*
    Provides an interface to the FFT packages.
*/

#include <../src/mat/impls/fft/fft.h> /*I "petscmat.h" I*/

static PetscErrorCode MatDestroy_FFT(Mat A)
{
  Mat_FFT *fft = (Mat_FFT *)A->data;

  PetscFunctionBegin;
  if (fft->matdestroy) PetscCall((fft->matdestroy)(A));
  PetscCall(PetscFree(fft->dim));
  PetscCall(PetscFree(A->data));
  PetscCall(PetscObjectChangeTypeName((PetscObject)A, NULL));
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@C
  MatCreateFFT - Creates a matrix object that provides FFT via an external package

  Collective

  Input Parameters:
+ comm    - MPI communicator
. ndim    - the ndim-dimensional transform
. dim     - array of size ndim, dim[i] contains the vector length in the i-dimension
- mattype - package type, e.g., `MATFFTW` or `MATSEQCUFFT`

  Output Parameter:
. A - the matrix

  Options Database Key:
. -mat_fft_type - set FFT type fft or seqcufft

  Level: intermediate

  Note:
  This serves as a base class for all FFT matrix classes, currently `MATFFTW` or `MATSEQCUFFT`

.seealso: [](ch_matrices), `Mat`, `MATFFTW`, `MATSEQCUFFT`, `MatCreateVecsFFTW()`
@*/
PetscErrorCode MatCreateFFT(MPI_Comm comm, PetscInt ndim, const PetscInt dim[], MatType mattype, Mat *A)
{
  PetscMPIInt size;
  Mat         FFT;
  PetscInt    N, i;
  Mat_FFT    *fft;

  PetscFunctionBegin;
  PetscAssertPointer(dim, 3);
  PetscAssertPointer(A, 5);
  PetscCheck(ndim >= 1, comm, PETSC_ERR_USER, "ndim %" PetscInt_FMT " must be > 0", ndim);
  PetscCallMPI(MPI_Comm_size(comm, &size));

  PetscCall(MatCreate(comm, &FFT));
  PetscCall(PetscNew(&fft));
  FFT->data = (void *)fft;
  N         = 1;
  for (i = 0; i < ndim; i++) {
    PetscCheck(dim[i] >= 1, PETSC_COMM_SELF, PETSC_ERR_USER, "dim[%" PetscInt_FMT "]=%" PetscInt_FMT " must be > 0", i, dim[i]);
    N *= dim[i];
  }

  PetscCall(PetscMalloc1(ndim, &fft->dim));
  PetscCall(PetscArraycpy(fft->dim, dim, ndim));

  fft->ndim = ndim;
  fft->n    = PETSC_DECIDE;
  fft->N    = N;
  fft->data = NULL;

  PetscCall(MatSetType(FFT, mattype));

  FFT->ops->destroy = MatDestroy_FFT;

  /* get runtime options... what options? */
  PetscObjectOptionsBegin((PetscObject)FFT);
  PetscOptionsEnd();

  *A = FFT;
  PetscFunctionReturn(PETSC_SUCCESS);
}