Mercurial > hg > octave-lyh

annotate scripts/polynomial/polyval.m @ 5102:b04b30d30c66

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
[project @ 2004-12-28 01:59:05 by jwe]
author jwe
date Tue, 28 Dec 2004 01:59:05 +0000
parents c08cb1098afc
children 4c8a2e4e0717
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
2847
8b262e771614 [project @ 1997-03-27 16:18:26 by jwe]
jwe
parents: 2716
diff changeset
1 ## Copyright (C) 1996, 1997 John W. Eaton
2313
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
2 ##
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
3 ## This file is part of Octave.
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
4 ##
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
5 ## Octave is free software; you can redistribute it and/or modify it
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
6 ## under the terms of the GNU General Public License as published by
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
7 ## the Free Software Foundation; either version 2, or (at your option)
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
8 ## any later version.
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
9 ##
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
10 ## Octave is distributed in the hope that it will be useful, but
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
11 ## WITHOUT ANY WARRANTY; without even the implied warranty of
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
13 ## General Public License for more details.
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
14 ##
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
15 ## You should have received a copy of the GNU General Public License
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
16 ## along with Octave; see the file COPYING. If not, write to the Free
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
17 ## Software Foundation, 59 Temple Place - Suite 330, Boston, MA
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe]
jwe
parents: 2312
diff changeset
18 ## 02111-1307, USA.
904
3470f1e25a79 [project @ 1994-11-09 21:22:15 by jwe]
jwe
parents: 561
diff changeset
19
3368
a4cd1e9d9962 [project @ 1999-11-20 17:22:48 by jwe]
jwe
parents: 3202
diff changeset
20 ## -*- texinfo -*-
a4cd1e9d9962 [project @ 1999-11-20 17:22:48 by jwe]
jwe
parents: 3202
diff changeset
21 ## @deftypefn {Function File} {} polyval (@var{c}, @var{x})
2311
2b5788792cad [project @ 1996-07-11 20:18:38 by jwe]
jwe
parents: 2303
diff changeset
22 ## Evaluate a polynomial.
3426
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3368
diff changeset
23 ##
3368
a4cd1e9d9962 [project @ 1999-11-20 17:22:48 by jwe]
jwe
parents: 3202
diff changeset
24 ## @code{polyval (@var{c}, @var{x})} will evaluate the polynomial at the
a4cd1e9d9962 [project @ 1999-11-20 17:22:48 by jwe]
jwe
parents: 3202
diff changeset
25 ## specified value of @var{x}.
3426
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3368
diff changeset
26 ##
3368
a4cd1e9d9962 [project @ 1999-11-20 17:22:48 by jwe]
jwe
parents: 3202
diff changeset
27 ## If @var{x} is a vector or matrix, the polynomial is evaluated at each of
a4cd1e9d9962 [project @ 1999-11-20 17:22:48 by jwe]
jwe
parents: 3202
diff changeset
28 ## the elements of @var{x}.
a4cd1e9d9962 [project @ 1999-11-20 17:22:48 by jwe]
jwe
parents: 3202
diff changeset
29 ## @end deftypefn
5053
c08cb1098afc [project @ 2004-10-19 23:10:54 by jwe]
jwe
parents: 4030
diff changeset
30 ##
3457
e031284eea27 [project @ 2000-01-19 08:49:56 by jwe]
jwe
parents: 3426
diff changeset
31 ## @seealso{polyvalm, poly, roots, conv, deconv, residue, filter,
e031284eea27 [project @ 2000-01-19 08:49:56 by jwe]
jwe
parents: 3426
diff changeset
32 ## polyderiv, and polyinteg}
1025
f558749713f1 [project @ 1995-01-11 20:52:10 by jwe]
jwe
parents: 904
diff changeset
33
3202
44d82b369c78 [project @ 1998-10-29 20:27:57 by jwe]
jwe
parents: 3085
diff changeset
34 ## Author: Tony Richardson <arichard@stark.cc.oh.us>
2312
204cc7db6f4a [project @ 1996-07-11 21:20:36 by jwe]
jwe
parents: 2311
diff changeset
35 ## Created: June 1994
204cc7db6f4a [project @ 1996-07-11 21:20:36 by jwe]
jwe
parents: 2311
diff changeset
36 ## Adapted-By: jwe
561
e79ff1f4df3c [project @ 1994-07-25 22:32:08 by jwe]
jwe
parents:
diff changeset
37
2312
204cc7db6f4a [project @ 1996-07-11 21:20:36 by jwe]
jwe
parents: 2311
diff changeset
38 function y = polyval (c, x)
561
e79ff1f4df3c [project @ 1994-07-25 22:32:08 by jwe]
jwe
parents:
diff changeset
39
1025
f558749713f1 [project @ 1995-01-11 20:52:10 by jwe]
jwe
parents: 904
diff changeset
40 if (nargin != 2)
f558749713f1 [project @ 1995-01-11 20:52:10 by jwe]
jwe
parents: 904
diff changeset
41 usage ("polyval (c, x)");
561
e79ff1f4df3c [project @ 1994-07-25 22:32:08 by jwe]
jwe
parents:
diff changeset
42 endif
e79ff1f4df3c [project @ 1994-07-25 22:32:08 by jwe]
jwe
parents:
diff changeset
43
4030
22bd65326ec1 [project @ 2002-08-09 18:58:13 by jwe]
jwe
parents: 3458
diff changeset
44 if (! (isvector (c) || isempty (c)))
3458
d25bc039237b [project @ 2000-01-19 09:36:14 by jwe]
jwe
parents: 3457
diff changeset
45 error ("polyval: first argument must be a vector");
561
e79ff1f4df3c [project @ 1994-07-25 22:32:08 by jwe]
jwe
parents:
diff changeset
46 endif
e79ff1f4df3c [project @ 1994-07-25 22:32:08 by jwe]
jwe
parents:
diff changeset
47
2716
2b5c27299cde [project @ 1997-02-22 08:40:55 by jwe]
jwe
parents: 2325
diff changeset
48 if (isempty (x))
2b5c27299cde [project @ 1997-02-22 08:40:55 by jwe]
jwe
parents: 2325
diff changeset
49 y = [];
2b5c27299cde [project @ 1997-02-22 08:40:55 by jwe]
jwe
parents: 2325
diff changeset
50 return;
2b5c27299cde [project @ 1997-02-22 08:40:55 by jwe]
jwe
parents: 2325
diff changeset
51 endif
2b5c27299cde [project @ 1997-02-22 08:40:55 by jwe]
jwe
parents: 2325
diff changeset
52
1025
f558749713f1 [project @ 1995-01-11 20:52:10 by jwe]
jwe
parents: 904
diff changeset
53 if (length (c) == 0)
561
e79ff1f4df3c [project @ 1994-07-25 22:32:08 by jwe]
jwe
parents:
diff changeset
54 y = c;
e79ff1f4df3c [project @ 1994-07-25 22:32:08 by jwe]
jwe
parents:
diff changeset
55 return;
e79ff1f4df3c [project @ 1994-07-25 22:32:08 by jwe]
jwe
parents:
diff changeset
56 endif
e79ff1f4df3c [project @ 1994-07-25 22:32:08 by jwe]
jwe
parents:
diff changeset
57
1025
f558749713f1 [project @ 1995-01-11 20:52:10 by jwe]
jwe
parents: 904
diff changeset
58 n = length (c);
f558749713f1 [project @ 1995-01-11 20:52:10 by jwe]
jwe
parents: 904
diff changeset
59 y = c (1) * ones (rows (x), columns (x));
561
e79ff1f4df3c [project @ 1994-07-25 22:32:08 by jwe]
jwe
parents:
diff changeset
60 for index = 2:n
1025
f558749713f1 [project @ 1995-01-11 20:52:10 by jwe]
jwe
parents: 904
diff changeset
61 y = c (index) + x .* y;
561
e79ff1f4df3c [project @ 1994-07-25 22:32:08 by jwe]
jwe
parents:
diff changeset
62 endfor
1025
f558749713f1 [project @ 1995-01-11 20:52:10 by jwe]
jwe
parents: 904
diff changeset
63
561
e79ff1f4df3c [project @ 1994-07-25 22:32:08 by jwe]
jwe
parents:
diff changeset
64 endfunction