Mercurial > octave-nkf

annotate scripts/polynomial/ppval.m @ 7017:a1dbe9d80eee

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
[project @ 2007-10-12 21:27:11 by jwe]
author jwe
date Fri, 12 Oct 2007 21:27:37 +0000
parents 93c65f2a5668
children 4fbaba9abec1
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
7017
a1dbe9d80eee [project @ 2007-10-12 21:27:11 by jwe]
jwe
parents: 7016
diff changeset
1 ## Copyright (C) 2000, 2006, 2007 Paul Kienzle
5824
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
2 ##
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
3 ## This file is part of Octave.
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
4 ##
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
5 ## Octave is free software; you can redistribute it and/or modify it
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
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.
5824
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
9 ##
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
10 ## Octave is distributed in the hope that it will be useful, but
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
11 ## WITHOUT ANY WARRANTY; without even the implied warranty of
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
13 ## General Public License for more details.
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
14 ##
448f9982e7fb [project @ 2006-05-19 06:53:31 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/>.
5824
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
18
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
19 ## -*- texinfo -*-
5831
b0d4ff99a0c5 [project @ 2006-05-26 21:06:00 by jwe]
jwe
parents: 5824
diff changeset
20 ## @deftypefn {Function File} {@var{yi} =} ppval (@var{pp}, @var{xi})
5824
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
21 ## Evaluate piece-wise polynomial @var{pp} at the points @var{xi}.
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
22 ## If @code{@var{pp}.d} is a scalar greater than 1, or an array,
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
23 ## then the returned value @var{yi} will be an array that is
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
24 ## @code{d1, d1, @dots{}, dk, length (@var{xi})]}.
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
25 ## @seealso{mkpp, unmkpp, spline}
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
26 ## @end deftypefn
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
27
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
28 function yi = ppval (pp, xi)
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
29
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
30 if (nargin != 2)
6046
34f96dd5441b [project @ 2006-10-10 16:10:25 by jwe]
jwe
parents: 6014
diff changeset
31 print_usage ();
5824
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
32 endif
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
33 if (! isstruct (pp))
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
34 error ("ppval: expects a pp structure");
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
35 endif
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
36 if (isempty (xi))
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
37 yi = [];
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
38 else
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
39 transposed = (columns (xi) == 1);
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
40 xi = xi(:);
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
41 xn = length (xi);
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
42 idx = lookup (pp.x(2:pp.n), xi) + 1;
6014
437f9086b967 [project @ 2006-09-30 15:27:06 by jwe]
jwe
parents: 5831
diff changeset
43 dx = (xi - pp.x(idx)).';
5824
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
44 dx = reshape (dx(ones(1,prod(pp.d)),:),[pp.d,xn]);
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
45 c = reshape (pp.P(:,1), pp.n, prod (pp.d));
6014
437f9086b967 [project @ 2006-09-30 15:27:06 by jwe]
jwe
parents: 5831
diff changeset
46 yi = reshape (c(idx,:).', [pp.d, xn]);
5824
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
47 for i = 2 : pp.k;
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
48 c = reshape (pp.P(:,i), pp.n, prod (pp.d));
6014
437f9086b967 [project @ 2006-09-30 15:27:06 by jwe]
jwe
parents: 5831
diff changeset
49 yi = yi .* dx + reshape (c(idx,:).', [pp.d, xn]);
5824
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
50 endfor
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
51 if (transposed && isscalar (pp.d) && pp.d == 1)
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
52 yi = yi.';
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
53 endif
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
54 endif
448f9982e7fb [project @ 2006-05-19 06:53:31 by jwe]
jwe
parents:
diff changeset
55 endfunction