Mercurial > octave-nkf
view src/DLD-FUNCTIONS/ifft.cc @ 4665:dece11da64ed ss-2-1-52
[project @ 2003-11-25 15:37:32 by jwe]
author | jwe |
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date | Tue, 25 Nov 2003 15:37:32 +0000 |
parents | ccfdb55c8156 |
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/* 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 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifdef HAVE_CONFIG_H #include <config.h> #endif #include "lo-mappers.h" #include "defun-dld.h" #include "error.h" #include "gripes.h" #include "oct-obj.h" #include "utils.h" // This function should be merged with Ffft. DEFUN_DLD (ifft, args, , "-*- texinfo -*-\n\ @deftypefn {Loadable Function} {} ifft (@var{a}, @var{n})\n\ Compute the inverse FFT of @var{a} using subroutines from @sc{Fftpack}. If\n\ @var{a} is a matrix, @code{fft} computes the inverse FFT for each column\n\ of @var{a}.\n\ \n\ If called with two arguments, @var{n} is expected to be an integer\n\ specifying the number of elements of @var{a} to use. If @var{a} is a\n\ matrix, @var{n} specifies the number of rows of @var{a} to use. If\n\ @var{n} is larger than the size of @var{a}, @var{a} is resized and\n\ padded with zeros.\n\ @end deftypefn") { octave_value retval; int nargin = args.length (); if (nargin < 1 || nargin > 2) { print_usage ("ifft"); return retval; } octave_value arg = args(0); int n_points = arg.rows (); if (n_points == 1) n_points = arg.columns (); if (nargin == 2) { double dval = args(1).double_value (); if (xisnan (dval)) error ("fft: NaN is invalid as the N_POINTS"); else n_points = NINT (dval); } if (error_state) return retval; if (n_points < 0) { error ("ifft: number of points must be greater than zero"); return retval; } int arg_is_empty = empty_arg ("ifft", arg.rows (), arg.columns ()); if (arg_is_empty < 0) return retval; else if (arg_is_empty || n_points == 0) return octave_value (Matrix ()); if (arg.is_real_type ()) { Matrix m = arg.matrix_value (); if (! error_state) { if (m.rows () == 1) m.resize (1, n_points, 0.0); else m.resize (n_points, m.columns (), 0.0); retval = m.ifourier (); } } else if (arg.is_complex_type ()) { ComplexMatrix m = arg.complex_matrix_value (); if (! error_state) { if (m.rows () == 1) m.resize (1, n_points, 0.0); else m.resize (n_points, m.columns (), 0.0); retval = m.ifourier (); } } else { gripe_wrong_type_arg ("ifft", arg); } return retval; } /* ;;; Local Variables: *** ;;; mode: C++ *** ;;; End: *** */