octave-lyh: scripts/signal/fftshift.m annotate

annotate scripts/signal/fftshift.m @ 12540:b3c158b8941c

Add tests for fftshift.m.

author	Robert T. Short <octave@phaselockedsystems.com.com>
date	Sat, 26 Mar 2011 06:42:35 -0700
parents	189baf055143
children	2783fa95cab7 914c0b103a3d

rev	line source
11523 fd0a3ac60b0e update copyright notices John W. Eaton <jwe@octave.org> parents: 11469 diff changeset	1 ## Copyright (C) 1997-2011 Vincent Cautaerts
3426 f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe] jwe parents: 3191 diff changeset	2 ##
3922 38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe] jwe parents: 3499 diff changeset	3 ## This file is part of Octave.
38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe] jwe parents: 3499 diff changeset	4 ##
38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe] jwe parents: 3499 diff changeset	5 ## Octave is free software; you can redistribute it and/or modify it
38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe] jwe parents: 3499 diff changeset	6 ## under the terms of the GNU General Public License as published by
7016 93c65f2a5668 [project @ 2007-10-12 06:40:56 by jwe] jwe parents: 6046 diff changeset	7 ## the Free Software Foundation; either version 3 of the License, or (at
93c65f2a5668 [project @ 2007-10-12 06:40:56 by jwe] jwe parents: 6046 diff changeset	8 ## your option) any later version.
3426 f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe] jwe parents: 3191 diff changeset	9 ##
3922 38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe] jwe parents: 3499 diff changeset	10 ## Octave is distributed in the hope that it will be useful, but
3191 e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	11 ## WITHOUT ANY WARRANTY; without even the implied warranty of
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
3426 f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe] jwe parents: 3191 diff changeset	13 ## General Public License for more details.
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe] jwe parents: 3191 diff changeset	14 ##
3191 e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	15 ## You should have received a copy of the GNU General Public License
7016 93c65f2a5668 [project @ 2007-10-12 06:40:56 by jwe] jwe parents: 6046 diff changeset	16 ## along with Octave; see the file COPYING. If not, see
93c65f2a5668 [project @ 2007-10-12 06:40:56 by jwe] jwe parents: 6046 diff changeset	17 ## <http://www.gnu.org/licenses/>.
3191 e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	18
3449 858695b3ed62 [project @ 2000-01-18 04:08:59 by jwe] jwe parents: 3426 diff changeset	19 ## -- texinfo --
11469 c776f063fefe Overhaul m-script files to use common variable name between code and documentation. Rik <octave@nomad.inbox5.com> parents: 10793 diff changeset	20 ## @deftypefn {Function File} {} fftshift (@var{x})
c776f063fefe Overhaul m-script files to use common variable name between code and documentation. Rik <octave@nomad.inbox5.com> parents: 10793 diff changeset	21 ## @deftypefnx {Function File} {} fftshift (@var{x}, @var{dim})
c776f063fefe Overhaul m-script files to use common variable name between code and documentation. Rik <octave@nomad.inbox5.com> parents: 10793 diff changeset	22 ## Perform a shift of the vector @var{x}, for use with the @code{fft}
3449 858695b3ed62 [project @ 2000-01-18 04:08:59 by jwe] jwe parents: 3426 diff changeset	23 ## and @code{ifft} functions, in order the move the frequency 0 to the
3499 3e3e14ad5149 [project @ 2000-01-31 05:18:07 by jwe] jwe parents: 3449 diff changeset	24 ## center of the vector or matrix.
3191 e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	25 ##
11469 c776f063fefe Overhaul m-script files to use common variable name between code and documentation. Rik <octave@nomad.inbox5.com> parents: 10793 diff changeset	26 ## If @var{x} is a vector of @math{N} elements corresponding to @math{N}
3499 3e3e14ad5149 [project @ 2000-01-31 05:18:07 by jwe] jwe parents: 3449 diff changeset	27 ## time samples spaced of @math{Dt} each, then @code{fftshift (fft
11469 c776f063fefe Overhaul m-script files to use common variable name between code and documentation. Rik <octave@nomad.inbox5.com> parents: 10793 diff changeset	28 ## (@var{x}))} corresponds to frequencies
3191 e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	29 ##
3449 858695b3ed62 [project @ 2000-01-18 04:08:59 by jwe] jwe parents: 3426 diff changeset	30 ## @example
4077 b5267e631ba8 [project @ 2002-09-27 22:48:46 by jwe] jwe parents: 4030 diff changeset	31 ## f = ((1:N) - ceil(N/2)) / N / Dt
3449 858695b3ed62 [project @ 2000-01-18 04:08:59 by jwe] jwe parents: 3426 diff changeset	32 ## @end example
3191 e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	33 ##
11587 c792872f8942 all script files: untabify and strip trailing whitespace John W. Eaton <jwe@octave.org> parents: 11523 diff changeset	34 ## If @var{x} is a matrix, the same holds for rows and columns. If
11469 c776f063fefe Overhaul m-script files to use common variable name between code and documentation. Rik <octave@nomad.inbox5.com> parents: 10793 diff changeset	35 ## @var{x} is an array, then the same holds along each dimension.
4844 9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	36 ##
9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	37 ## The optional @var{dim} argument can be used to limit the dimension
9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	38 ## along which the permutation occurs.
3449 858695b3ed62 [project @ 2000-01-18 04:08:59 by jwe] jwe parents: 3426 diff changeset	39 ## @end deftypefn
3191 e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	40
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	41 ## Author: Vincent Cautaerts <vincent@comf5.comm.eng.osaka-u.ac.jp>
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	42 ## Created: July 1997
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	43 ## Adapted-By: jwe
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	44
11469 c776f063fefe Overhaul m-script files to use common variable name between code and documentation. Rik <octave@nomad.inbox5.com> parents: 10793 diff changeset	45 function retval = fftshift (x, dim)
3191 e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	46
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	47 retval = 0;
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	48
4844 9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	49 if (nargin != 1 && nargin != 2)
6046 34f96dd5441b [project @ 2006-10-10 16:10:25 by jwe] jwe parents: 5307 diff changeset	50 print_usage ();
3191 e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	51 endif
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	52
4844 9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	53 if (nargin == 2)
9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	54 if (!isscalar (dim))
9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	55 error ("fftshift: dimension must be an integer scalar");
9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	56 endif
11469 c776f063fefe Overhaul m-script files to use common variable name between code and documentation. Rik <octave@nomad.inbox5.com> parents: 10793 diff changeset	57 nd = ndims (x);
c776f063fefe Overhaul m-script files to use common variable name between code and documentation. Rik <octave@nomad.inbox5.com> parents: 10793 diff changeset	58 sz = size (x);
4844 9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	59 sz2 = ceil (sz(dim) / 2);
9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	60 idx = cell ();
8507 cadc73247d65 style fixes John W. Eaton <jwe@octave.org> parents: 7208 diff changeset	61 for i = 1:nd
7208 a730e47fda4d [project @ 2007-11-28 02:32:41 by jwe] jwe parents: 7017 diff changeset	62 idx{i} = 1:sz(i);
4844 9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	63 endfor
7208 a730e47fda4d [project @ 2007-11-28 02:32:41 by jwe] jwe parents: 7017 diff changeset	64 idx{dim} = [sz2+1:sz(dim), 1:sz2];
11469 c776f063fefe Overhaul m-script files to use common variable name between code and documentation. Rik <octave@nomad.inbox5.com> parents: 10793 diff changeset	65 retval = x(idx{:});
3191 e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	66 else
11469 c776f063fefe Overhaul m-script files to use common variable name between code and documentation. Rik <octave@nomad.inbox5.com> parents: 10793 diff changeset	67 if (isvector (x))
12463 189baf055143 fftshift.m: Fix broken function documented in bug 32442 Karsten Trulsen <karstent@math.uio.no> parents: 11587 diff changeset	68 xl = length (x);
189baf055143 fftshift.m: Fix broken function documented in bug 32442 Karsten Trulsen <karstent@math.uio.no> parents: 11587 diff changeset	69 xx = ceil (xl/2);
189baf055143 fftshift.m: Fix broken function documented in bug 32442 Karsten Trulsen <karstent@math.uio.no> parents: 11587 diff changeset	70 retval = x([xx+1:xl, 1:xx]);
11469 c776f063fefe Overhaul m-script files to use common variable name between code and documentation. Rik <octave@nomad.inbox5.com> parents: 10793 diff changeset	71 elseif (ismatrix (x))
c776f063fefe Overhaul m-script files to use common variable name between code and documentation. Rik <octave@nomad.inbox5.com> parents: 10793 diff changeset	72 nd = ndims (x);
c776f063fefe Overhaul m-script files to use common variable name between code and documentation. Rik <octave@nomad.inbox5.com> parents: 10793 diff changeset	73 sz = size (x);
4844 9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	74 sz2 = ceil (sz ./ 2);
9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	75 idx = cell ();
8507 cadc73247d65 style fixes John W. Eaton <jwe@octave.org> parents: 7208 diff changeset	76 for i = 1:nd
4844 9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	77 idx{i} = [sz2(i)+1:sz(i), 1:sz2(i)];
9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	78 endfor
11469 c776f063fefe Overhaul m-script files to use common variable name between code and documentation. Rik <octave@nomad.inbox5.com> parents: 10793 diff changeset	79 retval = x(idx{:});
4844 9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	80 else
9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	81 error ("fftshift: expecting vector or matrix argument");
9f7ef92b50b0 [project @ 2004-04-02 17:26:53 by jwe] jwe parents: 4077 diff changeset	82 endif
3191 e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	83 endif
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	84
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe] jwe parents: diff changeset	85 endfunction
12540 b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	86
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	87 %!test
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	88 %! x = [0:7];
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	89 %! y = fftshift (x);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	90 %! assert(y, [4 5 6 7 0 1 2 3]);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	91 %! assert(fftshift (y), x);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	92
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	93 %!test
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	94 %! x = [0:6];
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	95 %! y = fftshift (x);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	96 %! assert(y, [4 5 6 0 1 2 3]);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	97 %! assert(fftshift (y), [1 2 3 4 5 6 0]);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	98
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	99 %!test
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	100 %! x = [0:7]';
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	101 %! y = fftshift (x);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	102 %! assert(y, [4;5;6;7;0;1;2;3]);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	103 %! assert(fftshift (y), x);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	104
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	105 %!test
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	106 %! x = [0:6]';
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	107 %! y = fftshift (x);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	108 %! assert(y, [4;5;6;0;1;2;3]);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	109 %! assert(fftshift (y), [1;2;3;4;5;6;0]);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	110
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	111 %!test
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	112 %! x = [0:3];
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	113 %! x = [x;2x;3x+1;4*x+1];
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	114 %! y = fftshift (x);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	115 %! assert(y, [[7 10 1 4];[9 13 1 5];[2 3 0 1];[4 6 0 2]]);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	116 %! assert(fftshift (y), x);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	117
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	118 %!test
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	119 %! x = [0:3];
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	120 %! x = [x;2x;3x+1;4*x+1];
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	121 %! y = fftshift (x,1);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	122 %! assert(y, [[1 4 7 10];[1 5 9 13];[0 1 2 3];[0 2 4 6]]);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	123 %! assert(fftshift (y,1), x);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	124
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	125 %!test
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	126 %! x = [0:3];
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	127 %! x = [x;2x;3x+1;4*x+1];
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	128 %! y = fftshift (x,2);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	129 %! assert(y, [[2 3 0 1];[4 6 0 2];[7 10 1 4];[9 13 1 5]]);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	130 %! assert(fftshift (y,2), x);
b3c158b8941c Add tests for fftshift.m. Robert T. Short <octave@phaselockedsystems.com.com> parents: 12463 diff changeset	131

Mercurial > hg > octave-lyh

annotate scripts/signal/fftshift.m @ 12540:b3c158b8941c