1 /** Various utility functions.
2 *
3 * Copyright 2008 Marco Cecchetti <mrcekets at gmail.com>
4 * Copyright 2007 Johan Engelen <goejendaagh@zonnet.nl>
5 * Copyright 2006 Michael G. Sloan <mgsloan@gmail.com>
6 *
7 * This library is free software; you can redistribute it and/or
8 * modify it either under the terms of the GNU Lesser General Public
9 * License version 2.1 as published by the Free Software Foundation
10 * (the "LGPL") or, at your option, under the terms of the Mozilla
11 * Public License Version 1.1 (the "MPL"). If you do not alter this
12 * notice, a recipient may use your version of this file under either
13 * the MPL or the LGPL.
14 *
15 * You should have received a copy of the LGPL along with this library
16 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 * You should have received a copy of the MPL along with this library
19 * in the file COPYING-MPL-1.1
20 *
21 * The contents of this file are subject to the Mozilla Public License
22 * Version 1.1 (the "License"); you may not use this file except in
23 * compliance with the License. You may obtain a copy of the License at
24 * http://www.mozilla.org/MPL/
25 *
26 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
27 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
28 * the specific language governing rights and limitations.
29 *
30 */
33 #include <2geom/utils.h>
36 namespace Geom
37 {
39 // return a vector that contains all the binomial coefficients of degree n
40 void binomial_coefficients(std::vector<size_t>& bc, size_t n)
41 {
42 size_t s = n+1;
43 bc.clear();
44 bc.resize(s);
45 bc[0] = 1;
46 size_t k;
47 for (size_t i = 1; i < n; ++i)
48 {
49 k = i >> 1;
50 if (i & 1u)
51 {
52 bc[k+1] = bc[k] << 1;
53 }
54 for (size_t j = k; j > 0; --j)
55 {
56 bc[j] += bc[j-1];
57 }
58 }
59 s >>= 1;
60 for (size_t i = 0; i < s; ++i)
61 {
62 bc[n-i] = bc[i];
63 }
64 }
66 } // end namespace Geom
78 /*
79 Local Variables:
80 mode:c++
81 c-file-style:"stroustrup"
82 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
83 indent-tabs-mode:nil
84 fill-column:99
85 End:
86 */
87 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :