Mercurial > hg > octave-nkf

annotate scripts/general/nextpow2.m @ 12541:dd2c70b30f28

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Add tests for ifftshift.m
author Robert T. Short <octave@phaselockedsystems.com.com>
date Sat, 26 Mar 2011 06:50:12 -0700
parents fd0a3ac60b0e
children 9e7ebbaf69ff
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
11523
fd0a3ac60b0e update copyright notices
John W. Eaton <jwe@octave.org>
parents: 11472
diff changeset
1 ## Copyright (C) 1995-2011 Kurt Hornik
3426
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3407
diff changeset
2 ##
3922
38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe]
jwe
parents: 3426
diff changeset
3 ## This file is part of Octave.
38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe]
jwe
parents: 3426
diff changeset
4 ##
38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe]
jwe
parents: 3426
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: 3426
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: 3407
diff changeset
9 ##
3922
38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe]
jwe
parents: 3426
diff changeset
10 ## Octave is distributed in the hope that it will be useful, but
2539
1dca28c213f0 [project @ 1996-11-19 23:54:48 by jwe]
jwe
parents:
diff changeset
11 ## WITHOUT ANY WARRANTY; without even the implied warranty of
1dca28c213f0 [project @ 1996-11-19 23:54:48 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: 3407
diff changeset
13 ## General Public License for more details.
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3407
diff changeset
14 ##
2539
1dca28c213f0 [project @ 1996-11-19 23:54:48 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/>.
2539
1dca28c213f0 [project @ 1996-11-19 23:54:48 by jwe]
jwe
parents:
diff changeset
18
3321
6923abb04e16 [project @ 1999-10-26 18:15:30 by jwe]
jwe
parents: 2816
diff changeset
19 ## -*- texinfo -*-
6923abb04e16 [project @ 1999-10-26 18:15:30 by jwe]
jwe
parents: 2816
diff changeset
20 ## @deftypefn {Function File} {} nextpow2 (@var{x})
9141
c1fff751b5a8 Update section 17.1 (Utility Functions) of arith.txi
Rik <rdrider0-list@yahoo.com>
parents: 8920
diff changeset
21 ## If @var{x} is a scalar, return the first integer @var{n} such that
3321
6923abb04e16 [project @ 1999-10-26 18:15:30 by jwe]
jwe
parents: 2816
diff changeset
22 ## @tex
9167
1231b1762a9a Simplify TeXinfo and eliminate use of @iftex in arith.txi
Rik <rdrider0-list@yahoo.com>
parents: 9141
diff changeset
23 ## $2^n \ge |x|$.
3321
6923abb04e16 [project @ 1999-10-26 18:15:30 by jwe]
jwe
parents: 2816
diff changeset
24 ## @end tex
8517
81d6ab3ac93c Allow documentation tobe built for other formats than tex and info
sh@sh-laptop
parents: 7017
diff changeset
25 ## @ifnottex
10793
be55736a0783 Grammarcheck the documentation from m-files.
Rik <octave@nomad.inbox5.com>
parents: 9167
diff changeset
26 ## 2^n @geq{} abs (x).
8517
81d6ab3ac93c Allow documentation tobe built for other formats than tex and info
sh@sh-laptop
parents: 7017
diff changeset
27 ## @end ifnottex
3426
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3407
diff changeset
28 ##
3321
6923abb04e16 [project @ 1999-10-26 18:15:30 by jwe]
jwe
parents: 2816
diff changeset
29 ## If @var{x} is a vector, return @code{nextpow2 (length (@var{x}))}.
9141
c1fff751b5a8 Update section 17.1 (Utility Functions) of arith.txi
Rik <rdrider0-list@yahoo.com>
parents: 8920
diff changeset
30 ## @seealso{pow2, log2}
3321
6923abb04e16 [project @ 1999-10-26 18:15:30 by jwe]
jwe
parents: 2816
diff changeset
31 ## @end deftypefn
2539
1dca28c213f0 [project @ 1996-11-19 23:54:48 by jwe]
jwe
parents:
diff changeset
32
5428
2a16423e4aa0 [project @ 2005-08-23 18:38:27 by jwe]
jwe
parents: 5307
diff changeset
33 ## Author: KH <Kurt.Hornik@wu-wien.ac.at>
2539
1dca28c213f0 [project @ 1996-11-19 23:54:48 by jwe]
jwe
parents:
diff changeset
34 ## Created: 7 October 1994
1dca28c213f0 [project @ 1996-11-19 23:54:48 by jwe]
jwe
parents:
diff changeset
35 ## Adapted-By: jwe
1dca28c213f0 [project @ 1996-11-19 23:54:48 by jwe]
jwe
parents:
diff changeset
36
1dca28c213f0 [project @ 1996-11-19 23:54:48 by jwe]
jwe
parents:
diff changeset
37 function n = nextpow2 (x)
3426
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3407
diff changeset
38
2539
1dca28c213f0 [project @ 1996-11-19 23:54:48 by jwe]
jwe
parents:
diff changeset
39 if (nargin != 1)
6046
34f96dd5441b [project @ 2006-10-10 16:10:25 by jwe]
jwe
parents: 5642
diff changeset
40 print_usage ();
2539
1dca28c213f0 [project @ 1996-11-19 23:54:48 by jwe]
jwe
parents:
diff changeset
41 endif
1dca28c213f0 [project @ 1996-11-19 23:54:48 by jwe]
jwe
parents:
diff changeset
42
4030
22bd65326ec1 [project @ 2002-08-09 18:58:13 by jwe]
jwe
parents: 3922
diff changeset
43 if (! (isscalar (x) || isvector (x)))
11472
1740012184f9 Use uppercase for variable names in error() strings to match Info documentation. Only m-files done.
Rik <octave@nomad.inbox5.com>
parents: 10793
diff changeset
44 error ("nextpow2: X must be a scalar or a vector");
2539
1dca28c213f0 [project @ 1996-11-19 23:54:48 by jwe]
jwe
parents:
diff changeset
45 endif
2816
ad4bf2a82b4f [project @ 1997-03-15 21:08:25 by jwe]
jwe
parents: 2539
diff changeset
46
ad4bf2a82b4f [project @ 1997-03-15 21:08:25 by jwe]
jwe
parents: 2539
diff changeset
47 t = length (x);
ad4bf2a82b4f [project @ 1997-03-15 21:08:25 by jwe]
jwe
parents: 2539
diff changeset
48 if (t > 1)
ad4bf2a82b4f [project @ 1997-03-15 21:08:25 by jwe]
jwe
parents: 2539
diff changeset
49 x = t;
ad4bf2a82b4f [project @ 1997-03-15 21:08:25 by jwe]
jwe
parents: 2539
diff changeset
50 endif
3426
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3407
diff changeset
51
2539
1dca28c213f0 [project @ 1996-11-19 23:54:48 by jwe]
jwe
parents:
diff changeset
52 [f, n] = log2 (abs (x));
1dca28c213f0 [project @ 1996-11-19 23:54:48 by jwe]
jwe
parents:
diff changeset
53 if (f == 0.5)
1dca28c213f0 [project @ 1996-11-19 23:54:48 by jwe]
jwe
parents:
diff changeset
54 n = n - 1;
1dca28c213f0 [project @ 1996-11-19 23:54:48 by jwe]
jwe
parents:
diff changeset
55 endif
3426
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3407
diff changeset
56
2539
1dca28c213f0 [project @ 1996-11-19 23:54:48 by jwe]
jwe
parents:
diff changeset
57 endfunction