--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/corefcn/fft.cc	Fri Jul 27 15:35:00 2012 -0700
@@ -0,0 +1,319 @@
+/*
+
+Copyright (C) 1997-2012 David Bateman
+Copyright (C) 1996-1997 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 3 of the License, 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, see
+<http://www.gnu.org/licenses/>.
+
+*/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "lo-mappers.h"
+
+#include "defun.h"
+#include "error.h"
+#include "gripes.h"
+#include "oct-obj.h"
+#include "utils.h"
+
+#if defined (HAVE_FFTW)
+#define FFTSRC "@sc{fftw}"
+#else
+#define FFTSRC "@sc{fftpack}"
+#endif
+
+static octave_value
+do_fft (const octave_value_list &args, const char *fcn, int type)
+{
+  octave_value retval;
+
+  int nargin = args.length ();
+
+  if (nargin < 1 || nargin > 3)
+    {
+      print_usage ();
+      return retval;
+    }
+
+  octave_value arg = args(0);
+  dim_vector dims = arg.dims ();
+  octave_idx_type n_points = -1;
+  int dim = -1;
+
+  if (nargin > 1)
+    {
+      if (! args(1).is_empty ())
+        {
+          double dval = args(1).double_value ();
+          if (xisnan (dval))
+            error ("%s: number of points (N) cannot be NaN", fcn);
+          else
+            {
+              n_points = NINTbig (dval);
+              if (n_points < 0)
+                error ("%s: number of points (N) must be greater than zero", fcn);
+            }
+        }
+    }
+
+  if (error_state)
+    return retval;
+
+  if (nargin > 2)
+    {
+      double dval = args(2).double_value ();
+      if (xisnan (dval))
+        error ("%s: DIM cannot be NaN", fcn);
+      else if (dval < 1 || dval > dims.length ())
+        error ("%s: DIM must be a valid dimension along which to perform FFT", fcn);
+      else
+        // to be safe, cast it back to int since dim is an int
+        dim = NINT (dval) - 1;
+    }
+
+  if (error_state)
+    return retval;
+
+  for (octave_idx_type i = 0; i < dims.length (); i++)
+    if (dims(i) < 0)
+      return retval;
+
+  if (dim < 0)
+    {
+      for (octave_idx_type i = 0; i < dims.length (); i++)
+        if (dims(i) > 1)
+          {
+            dim = i;
+            break;
+          }
+
+      // And if the first argument is scalar?
+      if (dim < 0)
+        dim = 1;
+    }
+
+  if (n_points < 0)
+    n_points = dims (dim);
+  else
+    dims (dim) = n_points;
+
+  if (dims.any_zero () || n_points == 0)
+    {
+      if (arg.is_single_type ())
+        return octave_value (FloatNDArray (dims));
+      else
+        return octave_value (NDArray (dims));
+    }
+
+  if (arg.is_single_type ())
+    {
+      if (arg.is_real_type ())
+        {
+          FloatNDArray nda = arg.float_array_value ();
+
+          if (! error_state)
+            {
+              nda.resize (dims, 0.0);
+              retval = (type != 0 ? nda.ifourier (dim) : nda.fourier (dim));
+            }
+        }
+      else
+        {
+          FloatComplexNDArray cnda = arg.float_complex_array_value ();
+
+          if (! error_state)
+            {
+              cnda.resize (dims, 0.0);
+              retval = (type != 0 ? cnda.ifourier (dim) : cnda.fourier (dim));
+            }
+        }
+    }
+  else
+    {
+      if (arg.is_real_type ())
+        {
+          NDArray nda = arg.array_value ();
+
+          if (! error_state)
+            {
+              nda.resize (dims, 0.0);
+              retval = (type != 0 ? nda.ifourier (dim) : nda.fourier (dim));
+            }
+        }
+      else if (arg.is_complex_type ())
+        {
+          ComplexNDArray cnda = arg.complex_array_value ();
+
+          if (! error_state)
+            {
+              cnda.resize (dims, 0.0);
+              retval = (type != 0 ? cnda.ifourier (dim) : cnda.fourier (dim));
+            }
+        }
+      else
+        {
+          gripe_wrong_type_arg (fcn, arg);
+        }
+    }
+
+  return retval;
+}
+
+/*
+%!assert (fft ([]), [])
+%!assert (fft (zeros (10,0)), zeros (10,0))
+%!assert (fft (zeros (0,10)), zeros (0,10))
+%!assert (fft (0), 0)
+%!assert (fft (1), 1)
+%!assert (fft (ones (2,2)), [2,2; 0,0])
+%!assert (fft (eye (2,2)), [1,1; 1,-1])
+
+%!assert (fft (single ([])), single ([]))
+%!assert (fft (zeros (10,0,"single")), zeros (10,0,"single"))
+%!assert (fft (zeros (0,10,"single")), zeros (0,10,"single"))
+%!assert (fft (single (0)), single (0))
+%!assert (fft (single (1)), single (1))
+%!assert (fft (ones (2,2,"single")), single ([2,2; 0,0]))
+%!assert (fft (eye (2,2,"single")), single ([1,1; 1,-1]))
+
+%!error (fft ())
+*/
+
+
+DEFUN (fft, args, ,
+  "-*- texinfo -*-\n\
+@deftypefn  {Built-in Function} {} fft (@var{x})\n\
+@deftypefnx {Built-in Function} {} fft (@var{x}, @var{n})\n\
+@deftypefnx {Built-in Function} {} fft (@var{x}, @var{n}, @var{dim})\n\
+Compute the discrete Fourier transform of @var{A} using\n\
+a Fast Fourier Transform (FFT) algorithm.\n\
+\n\
+The FFT is calculated along the first non-singleton dimension of the\n\
+array.  Thus if @var{x} is a matrix, @code{fft (@var{x})} computes the\n\
+FFT for each column of @var{x}.\n\
+\n\
+If called with two arguments, @var{n} is expected to be an integer\n\
+specifying the number of elements of @var{x} to use, or an empty\n\
+matrix to specify that its value should be ignored.  If @var{n} is\n\
+larger than the dimension along which the FFT is calculated, then\n\
+@var{x} is resized and padded with zeros.  Otherwise, if @var{n} is\n\
+smaller than the dimension along which the FFT is calculated, then\n\
+@var{x} is truncated.\n\
+\n\
+If called with three arguments, @var{dim} is an integer specifying the\n\
+dimension of the matrix along which the FFT is performed\n\
+@seealso{ifft, fft2, fftn, fftw}\n\
+@end deftypefn")
+{
+  return do_fft (args, "fft", 0);
+}
+
+
+DEFUN (ifft, args, ,
+  "-*- texinfo -*-\n\
+@deftypefn  {Built-in Function} {} ifft (@var{x})\n\
+@deftypefnx {Built-in Function} {} ifft (@var{x}, @var{n})\n\
+@deftypefnx {Built-in Function} {} ifft (@var{x}, @var{n}, @var{dim})\n\
+Compute the inverse discrete Fourier transform of @var{A}\n\
+using a Fast Fourier Transform (FFT) algorithm.\n\
+\n\
+The inverse FFT is calculated along the first non-singleton dimension\n\
+of the array.  Thus if @var{x} is a matrix, @code{fft (@var{x})} computes\n\
+the inverse FFT for each column of @var{x}.\n\
+\n\
+If called with two arguments, @var{n} is expected to be an integer\n\
+specifying the number of elements of @var{x} to use, or an empty\n\
+matrix to specify that its value should be ignored.  If @var{n} is\n\
+larger than the dimension along which the inverse FFT is calculated, then\n\
+@var{x} is resized and padded with zeros.  Otherwise, if @var{n} is\n\
+smaller than the dimension along which the inverse FFT is calculated,\n\
+then @var{x} is truncated.\n\
+\n\
+If called with three arguments, @var{dim} is an integer specifying the\n\
+dimension of the matrix along which the inverse FFT is performed\n\
+@seealso{fft, ifft2, ifftn, fftw}\n\
+@end deftypefn")
+{
+  return do_fft (args, "ifft", 1);
+}
+
+/*
+%% Author: David Billinghurst (David.Billinghurst@riotinto.com.au)
+%%         Comalco Research and Technology
+%%         02 May 2000
+%!test
+%! N = 64;
+%! n = 4;
+%! t = 2*pi*(0:1:N-1)/N;
+%! s = cos (n*t);
+%! S = fft (s);
+%!
+%! answer = zeros (size (t));
+%! answer(n+1) = N/2;
+%! answer(N-n+1) = N/2;
+%!
+%! assert (S, answer, 4*N*eps);
+
+%% Author: David Billinghurst (David.Billinghurst@riotinto.com.au)
+%%         Comalco Research and Technology
+%%         02 May 2000
+%!test
+%! N = 64;
+%! n = 7;
+%! t = 2*pi*(0:1:N-1)/N;
+%! s = cos (n*t);
+%!
+%! S = zeros (size (t));
+%! S(n+1) = N/2;
+%! S(N-n+1) = N/2;
+%!
+%! assert (ifft (S), s, 4*N*eps);
+
+%% Author: David Billinghurst (David.Billinghurst@riotinto.com.au)
+%%         Comalco Research and Technology
+%%         02 May 2000
+%!test
+%! N = 64;
+%! n = 4;
+%! t = single (2*pi*(0:1:N-1)/N);
+%! s = cos (n*t);
+%! S = fft (s);
+%!
+%! answer = zeros (size (t), "single");
+%! answer(n+1) = N/2;
+%! answer(N-n+1) = N/2;
+%!
+%! assert (S, answer, 4*N*eps ("single"));
+
+%% Author: David Billinghurst (David.Billinghurst@riotinto.com.au)
+%%         Comalco Research and Technology
+%%         02 May 2000
+%!test
+%! N = 64;
+%! n = 7;
+%! t = 2*pi*(0:1:N-1)/N;
+%! s = cos (n*t);
+%!
+%! S = zeros (size (t), "single");
+%! S(n+1) = N/2;
+%! S(N-n+1) = N/2;
+%!
+%! assert (ifft (S), s, 4*N*eps ("single"));
+*/