132 lines
3.6 KiB
C++
132 lines
3.6 KiB
C++
/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
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/*
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* Main authors:
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* Vincent Barichard <Vincent.Barichard@univ-angers.fr>
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*
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* Copyright:
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* Vincent Barichard, 2012
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*
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* This file is part of Gecode, the generic constraint
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* development environment:
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* http://www.gecode.org
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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*/
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#include <gecode/driver.hh>
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#include <gecode/minimodel.hh>
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#include <gecode/float.hh>
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using namespace Gecode;
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/**
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* \brief %Example: Golden spiral
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*
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* The Golden Spiral is a logarithmic spiral whose growth factor
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* is the golden ratio \f$\phi=1,618\f$.
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*
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* It is defined by the polar equation:
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* \f[
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* r = ae^{b\theta}
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* \f]
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* where
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* \f[
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* \operatorname{abs}(b) = \frac{\operatorname{ln}(\phi)}{\frac{\pi}{2}}
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* \f]
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*
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* To get cartesian coordinates, it can be solved for \f$x\f$
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* and \f$y\f$ in terms of \f$r\f$ and \f$\theta\f$.
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* By setting \f$a=1\f$, it yields to the equation:
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*
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* \f[
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* r = e^{0.30649\times\theta}
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* \f]
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* with
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* \f[
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* x=r\operatorname{cos}(\theta), \quad y=r\operatorname{sin}(\theta)
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* \f]
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*
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* The tuple \f$(r,\theta)\f$ is related to the position for
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* \f$x\f$ and \f$y\f$ on the curve. \f$r\f$ and \f$\theta\f$
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* are positive numbers.
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*
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* To get reasonable interval starting sizes, \f$x\f$ and \f$y\f$
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* are restricted to \f$[-20;20]\f$.
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*
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* \ingroup Example
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*/
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class GoldenSpiral : public FloatMaximizeScript {
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protected:
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/// The numbers
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FloatVarArray f;
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public:
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/// Actual model
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GoldenSpiral(const Options& opt)
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: FloatMaximizeScript(opt), f(*this,4,-20,20) {
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// Post equation
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FloatVar theta = f[0];
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FloatVar r = f[3];
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FloatVar x = f[1];
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FloatVar y = f[2];
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rel(*this, theta >= 0);
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rel(*this, r >= 0);
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rel(*this, r*cos(theta) == x);
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rel(*this, r*sin(theta) == y);
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rel(*this, exp(0.30649*theta) == r);
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branch(*this,theta,FLOAT_VAL_SPLIT_MIN());
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}
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/// Constructor for cloning \a p
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GoldenSpiral(GoldenSpiral& p)
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: FloatMaximizeScript(p) {
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f.update(*this, p.f);
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}
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/// Copy during cloning
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virtual Space* copy(void) {
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return new GoldenSpiral(*this);
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}
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/// Cost function
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virtual FloatVar cost(void) const {
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return f[0];
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}
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/// Print solution coordinates
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virtual void print(std::ostream& os) const {
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os << "XY " << f[1].med() << " " << f[2].med()
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<< std::endl;
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}
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};
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/** \brief Main-function
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* \relates GoldenSpiral
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*/
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int main(int argc, char* argv[]) {
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Options opt("GoldenSpiral");
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opt.solutions(0);
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opt.step(0.1);
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opt.parse(argc,argv);
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FloatMaximizeScript::run<GoldenSpiral,BAB,Options>(opt);
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return 0;
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}
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// STATISTICS: example-any
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