// f-fft.cc                                           -*- C++ -*-
/*

Copyright (C) 1993, 1994 John W. Eaton

This file is part of Octave.

Octave is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2, or (at your option) any
later version.

Octave is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, write to the Free
Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "dMatrix.h"
#include "CMatrix.h"

#include "tree-const.h"
#include "user-prefs.h"
#include "gripes.h"
#include "error.h"
#include "f-fft.h"

#ifdef WITH_DLD
Octave_object
builtin_fft_2 (const Octave_object& args, int nargout)
{
  Octave_object retval (1);
  retval(0) = fft (args(1));
  return retval;
}
#endif

tree_constant
fft (const tree_constant& a)
{
  tree_constant retval;

  tree_constant tmp = a.make_numeric ();;
    
  if (tmp.rows () == 0 || tmp.columns () == 0)
    {
      int flag = user_pref.propagate_empty_matrices;
      if (flag != 0)
	{
	  if (flag < 0)
	    gripe_empty_arg ("fft", 0);
	  Matrix m;
	  retval = tree_constant (m);
	}
      else
	gripe_empty_arg ("fft", 1);

      return retval;
    }

  switch (tmp.const_type ())
    {
    case tree_constant_rep::matrix_constant:
      {
	Matrix m = tmp.matrix_value ();
	ComplexMatrix mfft = m.fourier ();
	retval = tree_constant (mfft);
      }
      break;
    case tree_constant_rep::complex_matrix_constant:
      {
	ComplexMatrix m = tmp.complex_matrix_value ();
	ComplexMatrix mfft = m.fourier ();
	retval = tree_constant (mfft);
      }
      break;
    case tree_constant_rep::scalar_constant:
    case tree_constant_rep::complex_scalar_constant:
      error ("fft: invalid scalar argument");
      break;
    default:
      panic_impossible ();
      break;
    }
  return retval;
}

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