Mercurial > hg > octave-lyh

annotate scripts/specfun/pow2.m @ 10453:7d23c19249d6

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
NEWS: style fixes
author John W. Eaton <jwe@octave.org>
date Wed, 24 Mar 2010 16:26:33 -0400
parents 1231b1762a9a
children be55736a0783
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
8920
eb63fbe60fab update copyright notices
John W. Eaton <jwe@octave.org>
parents: 8517
diff changeset
1 ## Copyright (C) 1995, 1996, 1999, 2000, 2002, 2004, 2005, 2006, 2007,
eb63fbe60fab update copyright notices
John W. Eaton <jwe@octave.org>
parents: 8517
diff changeset
2 ## 2008, 2009 Kurt Hornik
3426
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3407
diff changeset
3 ##
3922
38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe]
jwe
parents: 3456
diff changeset
4 ## This file is part of Octave.
38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe]
jwe
parents: 3456
diff changeset
5 ##
38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe]
jwe
parents: 3456
diff changeset
6 ## Octave is free software; you can redistribute it and/or modify it
38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe]
jwe
parents: 3456
diff changeset
7 ## 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
8 ## 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
9 ## your option) any later version.
3426
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3407
diff changeset
10 ##
3922
38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe]
jwe
parents: 3456
diff changeset
11 ## Octave is distributed in the hope that it will be useful, but
2537
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
12 ## WITHOUT ANY WARRANTY; without even the implied warranty of
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
13 ## 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
14 ## General Public License for more details.
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3407
diff changeset
15 ##
2537
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
16 ## 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
17 ## 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
18 ## <http://www.gnu.org/licenses/>.
2537
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
19
3321
6923abb04e16 [project @ 1999-10-26 18:15:30 by jwe]
jwe
parents: 2537
diff changeset
20 ## -*- texinfo -*-
6923abb04e16 [project @ 1999-10-26 18:15:30 by jwe]
jwe
parents: 2537
diff changeset
21 ## @deftypefn {Mapping Function} {} pow2 (@var{x})
6923abb04e16 [project @ 1999-10-26 18:15:30 by jwe]
jwe
parents: 2537
diff changeset
22 ## @deftypefnx {Mapping Function} {} pow2 (@var{f}, @var{e})
6923abb04e16 [project @ 1999-10-26 18:15:30 by jwe]
jwe
parents: 2537
diff changeset
23 ## With one argument, computes
6923abb04e16 [project @ 1999-10-26 18:15:30 by jwe]
jwe
parents: 2537
diff changeset
24 ## @tex
9167
1231b1762a9a Simplify TeXinfo and eliminate use of @iftex in arith.txi
Rik <rdrider0-list@yahoo.com>
parents: 9141
diff changeset
25 ## $2^x$
3321
6923abb04e16 [project @ 1999-10-26 18:15:30 by jwe]
jwe
parents: 2537
diff changeset
26 ## @end tex
8517
81d6ab3ac93c Allow documentation tobe built for other formats than tex and info
sh@sh-laptop
parents: 7742
diff changeset
27 ## @ifnottex
9167
1231b1762a9a Simplify TeXinfo and eliminate use of @iftex in arith.txi
Rik <rdrider0-list@yahoo.com>
parents: 9141
diff changeset
28 ## 2 .^ x
8517
81d6ab3ac93c Allow documentation tobe built for other formats than tex and info
sh@sh-laptop
parents: 7742
diff changeset
29 ## @end ifnottex
9141
c1fff751b5a8 Update section 17.1 (Utility Functions) of arith.txi
Rik <rdrider0-list@yahoo.com>
parents: 8920
diff changeset
30 ## for each element of @var{x}.
c1fff751b5a8 Update section 17.1 (Utility Functions) of arith.txi
Rik <rdrider0-list@yahoo.com>
parents: 8920
diff changeset
31 ##
c1fff751b5a8 Update section 17.1 (Utility Functions) of arith.txi
Rik <rdrider0-list@yahoo.com>
parents: 8920
diff changeset
32 ## With two arguments, returns
3321
6923abb04e16 [project @ 1999-10-26 18:15:30 by jwe]
jwe
parents: 2537
diff changeset
33 ## @tex
9167
1231b1762a9a Simplify TeXinfo and eliminate use of @iftex in arith.txi
Rik <rdrider0-list@yahoo.com>
parents: 9141
diff changeset
34 ## $f \cdot 2^e$.
3321
6923abb04e16 [project @ 1999-10-26 18:15:30 by jwe]
jwe
parents: 2537
diff changeset
35 ## @end tex
8517
81d6ab3ac93c Allow documentation tobe built for other formats than tex and info
sh@sh-laptop
parents: 7742
diff changeset
36 ## @ifnottex
9167
1231b1762a9a Simplify TeXinfo and eliminate use of @iftex in arith.txi
Rik <rdrider0-list@yahoo.com>
parents: 9141
diff changeset
37 ## f .* (2 .^ e).
8517
81d6ab3ac93c Allow documentation tobe built for other formats than tex and info
sh@sh-laptop
parents: 7742
diff changeset
38 ## @end ifnottex
9141
c1fff751b5a8 Update section 17.1 (Utility Functions) of arith.txi
Rik <rdrider0-list@yahoo.com>
parents: 8920
diff changeset
39 ## @seealso{log2, nextpow2}
3321
6923abb04e16 [project @ 1999-10-26 18:15:30 by jwe]
jwe
parents: 2537
diff changeset
40 ## @end deftypefn
2537
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
41
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
42 ## Author: AW <Andreas.Weingessel@ci.tuwien.ac.at>
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
43 ## Created: 17 October 1994
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
44 ## Adapted-By: jwe
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
45
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
46 function y = pow2 (f, e)
3426
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3407
diff changeset
47
2537
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
48 if (nargin == 1)
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
49 y = 2 .^ f;
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
50 elseif (nargin == 2)
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
51 y = f .* (2 .^ e);
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
52 else
6046
34f96dd5441b [project @ 2006-10-10 16:10:25 by jwe]
jwe
parents: 5642
diff changeset
53 print_usage ();
2537
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
54 endif
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
55
80b982e7f4b1 [project @ 1996-11-19 21:15:06 by jwe]
jwe
parents:
diff changeset
56 endfunction
7385
8b7b4f58199f [project @ 2008-01-15 20:49:09 by jwe]
jwe
parents: 7017
diff changeset
57
8b7b4f58199f [project @ 2008-01-15 20:49:09 by jwe]
jwe
parents: 7017
diff changeset
58 %!test
8b7b4f58199f [project @ 2008-01-15 20:49:09 by jwe]
jwe
parents: 7017
diff changeset
59 %! x = [3, 0, -3];
8b7b4f58199f [project @ 2008-01-15 20:49:09 by jwe]
jwe
parents: 7017
diff changeset
60 %! v = [8, 1, .125];
8b7b4f58199f [project @ 2008-01-15 20:49:09 by jwe]
jwe
parents: 7017
diff changeset
61 %! assert(all (abs (pow2 (x) - v) < sqrt (eps)));
8b7b4f58199f [project @ 2008-01-15 20:49:09 by jwe]
jwe
parents: 7017
diff changeset
62
8b7b4f58199f [project @ 2008-01-15 20:49:09 by jwe]
jwe
parents: 7017
diff changeset
63 %!test
8b7b4f58199f [project @ 2008-01-15 20:49:09 by jwe]
jwe
parents: 7017
diff changeset
64 %! x = [3, 0, -3, 4, 0, -4, 5, 0, -5];
8b7b4f58199f [project @ 2008-01-15 20:49:09 by jwe]
jwe
parents: 7017
diff changeset
65 %! y = [-2, -2, -2, 1, 1, 1, 3, 3, 3];
8b7b4f58199f [project @ 2008-01-15 20:49:09 by jwe]
jwe
parents: 7017
diff changeset
66 %! z = x .* (2 .^ y);
7742
95ecf219a582 fix tests
John W. Eaton <jwe@octave.org>
parents: 7385
diff changeset
67 %! assert(all (abs (pow2 (x,y) - z) < sqrt (eps)));
7385
8b7b4f58199f [project @ 2008-01-15 20:49:09 by jwe]
jwe
parents: 7017
diff changeset
68
8b7b4f58199f [project @ 2008-01-15 20:49:09 by jwe]
jwe
parents: 7017
diff changeset
69 %!error pow2();
8b7b4f58199f [project @ 2008-01-15 20:49:09 by jwe]
jwe
parents: 7017
diff changeset
70