/* nag_sum_fft_complex_1d (c06pcc) Example Program.
 *
 * Copyright 2021 Numerical Algorithms Group.
 *
 * Mark 27.2, 2021.
 */

#include <nag.h>
#include <stdio.h>

int main(void) {
  /* Scalars */
  Integer exit_status = 0, i, n;
  /* Arrays */
  Complex *x = 0, *z = 0, *x_back = 0;
  /* Nag Types */
  NagError fail;

  INIT_FAIL(fail);

  printf("nag_sum_fft_complex_1d (c06pcc) Example Program Results\n");

  /* Read dimensions of array and array values from data file. */
  scanf("%*[^\n] %" NAG_IFMT "%*[^\n]", &n);
  if (!(x = NAG_ALLOC(n, Complex)) || !(z = NAG_ALLOC(n, Complex)) ||
      !(x_back = NAG_ALLOC(n, Complex))) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }
  for (i = 0; i < n; ++i) {
    scanf(" ( %lf, %lf )", &x[i].re, &x[i].im);
    z[i] = x[i];
  }

  /* Compute discrete Fourier transform of complex array x using
   * nag_sum_fft_complex_1d (c06pcc).
   */
  nag_sum_fft_complex_1d(Nag_ForwardTransform, z, n, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_sum_fft_complex_1d (c06pcc).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }

  for (i = 0; i < n; ++i)
    x_back[i] = z[i];

  /* Compute inverse discrete Fourier transform of complex array z using
   * nag_sum_fft_complex_1d (c06pcc).
   */
  nag_sum_fft_complex_1d(Nag_BackwardTransform, x_back, n, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_sum_fft_complex_1d (c06pcc).\n%s\n", fail.message);
    exit_status = 2;
    goto END;
  }

  printf("\n%2s%13s%28s%22s\n", "i", "x", "z = FFT(x)", "InvFFT(z)");
  for (i = 0; i < n; i++)
    printf("%2" NAG_IFMT
           " (%8.5f,  %8.5f ) (%8.5f,  %8.5f ) (%8.5f,  %8.5f )\n",
           i, x[i].re, x[i].im, z[i].re, z[i].im, x_back[i].re, x_back[i].im);
END:
  NAG_FREE(x);
  NAG_FREE(z);
  NAG_FREE(x_back);

  return exit_status;
}