153 lines
4.0 KiB
C++
153 lines
4.0 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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* Christian Schulte <schulte@gecode.org>
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*
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* Copyright:
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* Christian Schulte, 2001
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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/int.hh>
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#include <gecode/minimodel.hh>
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using namespace Gecode;
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/**
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* \brief %Example: Magic squares
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*
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* Compute magic squares of arbitrary size
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*
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* See problem 19 at http://www.csplib.org/.
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*
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* \ingroup Example
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*
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*/
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class MagicSquare : public Script {
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private:
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/// Size of magic square
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const int n;
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/// Fields of square
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IntVarArray x;
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public:
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/// Branching to use for model
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enum {
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BRANCH_SIZE, ///< Branch by size
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BRANCH_AFC_SIZE ///< Branch by size over AFC
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};
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/// Post constraints
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MagicSquare(const SizeOptions& opt)
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: Script(opt), n(opt.size()), x(*this,n*n,1,n*n) {
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// Number of fields on square
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const int nn = n*n;
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// Sum of all a row, column, or diagonal
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const int s = nn*(nn+1) / (2*n);
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// Matrix-wrapper for the square
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Matrix<IntVarArray> m(x, n, n);
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for (int i = n; i--; ) {
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linear(*this, m.row(i), IRT_EQ, s, opt.ipl());
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linear(*this, m.col(i), IRT_EQ, s, opt.ipl());
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}
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// Both diagonals must have sum s
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{
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IntVarArgs d1y(n);
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IntVarArgs d2y(n);
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for (int i = n; i--; ) {
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d1y[i] = m(i,i);
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d2y[i] = m(n-i-1,i);
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}
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linear(*this, d1y, IRT_EQ, s, opt.ipl());
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linear(*this, d2y, IRT_EQ, s, opt.ipl());
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}
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// All fields must be distinct
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distinct(*this, x, opt.ipl());
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// Break some (few) symmetries
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rel(*this, m(0,0), IRT_GR, m(0,n-1));
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rel(*this, m(0,0), IRT_GR, m(n-1,0));
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switch (opt.branching()) {
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case BRANCH_SIZE:
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branch(*this, x, INT_VAR_SIZE_MIN(), INT_VAL_SPLIT_MIN());
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break;
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case BRANCH_AFC_SIZE:
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branch(*this, x, INT_VAR_AFC_SIZE_MAX(opt.decay()), INT_VAL_SPLIT_MIN());
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break;
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}
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}
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/// Constructor for cloning \a s
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MagicSquare(MagicSquare& s) : Script(s), n(s.n) {
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x.update(*this, s.x);
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}
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/// Copy during cloning
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virtual Space*
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copy(void) {
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return new MagicSquare(*this);
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}
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/// Print solution
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virtual void
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print(std::ostream& os) const {
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// Matrix-wrapper for the square
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Matrix<IntVarArray> m(x, n, n);
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for (int i = 0; i<n; i++) {
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os << "\t";
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for (int j = 0; j<n; j++) {
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os.width(2);
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os << m(i,j) << " ";
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}
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os << std::endl;
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}
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}
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};
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/** \brief Main-function
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* \relates MagicSquare
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*/
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int
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main(int argc, char* argv[]) {
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SizeOptions opt("MagicSquare");
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opt.iterations(1);
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opt.size(7);
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opt.branching(MagicSquare::BRANCH_SIZE);
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opt.branching(MagicSquare::BRANCH_SIZE, "size");
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opt.branching(MagicSquare::BRANCH_AFC_SIZE, "afc-size");
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opt.parse(argc,argv);
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Script::run<MagicSquare,DFS,SizeOptions>(opt);
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return 0;
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}
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// STATISTICS: example-any
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