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dekker.one
1/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
2/*
3 * Main authors:
4 * Vincent Barichard <Vincent.Barichard@univ-angers.fr>
5 *
6 * Copyright:
7 * Vincent Barichard, 2012
8 *
9 * This file is part of Gecode, the generic constraint
10 * development environment:
11 * http://www.gecode.org
12 *
13 * Permission is hereby granted, free of charge, to any person obtaining
14 * a copy of this software and associated documentation files (the
15 * "Software"), to deal in the Software without restriction, including
16 * without limitation the rights to use, copy, modify, merge, publish,
17 * distribute, sublicense, and/or sell copies of the Software, and to
18 * permit persons to whom the Software is furnished to do so, subject to
19 * the following conditions:
20 *
21 * The above copyright notice and this permission notice shall be
22 * included in all copies or substantial portions of the Software.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
28 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
29 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
30 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
31 *
32 */
33
34#include <gecode/driver.hh>
35
36#include <gecode/minimodel.hh>
37#include <gecode/float.hh>
38
39using namespace Gecode;
40
41/**
42 * \brief %Example: Archimedean spiral
43 *
44 * The Archimedean Spiral is a spiral where all points
45 * corresponding to the locations over time of a point moving
46 * away from a fixed point with a constant speed along a line
47 * which rotates with constant angular velocity. It is defined
48 * by the polar equation:
49 * \f[ r = a+b\theta \f]
50 *
51 * To get cartesian coordinates, it can be solved for \f$x\f$
52 * and \f$y\f$ in terms of \f$r\f$ and \f$\theta\f$.
53 * By setting \f$a=1\f$ and \f$b=1\f$, it yields to the equation:
54 *
55 * \f[ r = \theta \f] with \f[ x=r\operatorname{cos}(\theta),
56 * \quad y=r\operatorname{sin}(\theta) \f]
57 *
58 * The tuple \f$(r,\theta)\f$ is related to the position for
59 * \f$x\f$ and \f$y\f$ on the curve. \f$r\f$ and \f$\theta\f$
60 * are positive numbers.
61 *
62 * To get reasonable interval starting * sizes, \f$x\f$ and
63 * \f$y\f$ are restricted to \f$[-20;20]\f$.
64 *
65 * \ingroup Example
66 */
67class ArchimedeanSpiral : public FloatMaximizeScript {
68protected:
69 /// The numbers
70 FloatVarArray f;
71public:
72 /// Actual model
73 ArchimedeanSpiral(const Options& opt)
74 : FloatMaximizeScript(opt), f(*this,4,-20,20) {
75 // Post equation
76 FloatVar theta = f[0];
77 FloatVar r = f[3];
78 FloatVar x = f[1];
79 FloatVar y = f[2];
80
81 rel(*this, theta >= 0);
82 rel(*this, theta <= 6*FloatVal::pi());
83 rel(*this, r >= 0);
84 rel(*this, r*cos(theta) == x);
85 rel(*this, r*sin(theta) == y);
86 rel(*this, r == theta);
87
88 branch(*this,f[0],FLOAT_VAL_SPLIT_MIN());
89 }
90 /// Constructor for cloning \a p
91 ArchimedeanSpiral(ArchimedeanSpiral& p)
92 : FloatMaximizeScript(p) {
93 f.update(*this, p.f);
94 }
95 /// Copy during cloning
96 virtual Space* copy(void) {
97 return new ArchimedeanSpiral(*this);
98 }
99 /// Cost function
100 virtual FloatVar cost(void) const {
101 return f[0];
102 }
103 /// Print solution coordinates
104 virtual void print(std::ostream& os) const {
105 os << "XY " << f[1].med() << " " << f[2].med()
106 << std::endl;
107 }
108
109};
110
111/** \brief Main-function
112 * \relates ArchimedeanSpiral
113 */
114int main(int argc, char* argv[]) {
115 Options opt("ArchimedeanSpiral");
116 opt.solutions(0);
117 opt.step(0.1);
118 opt.parse(argc,argv);
119 FloatMaximizeScript::run<ArchimedeanSpiral,BAB,Options>(opt);
120 return 0;
121}
122
123// STATISTICS: example-any