1.1 --- a/src/work/marci/lp/magic_square.cc	Sun Apr 17 18:57:22 2005 +0000
     1.2 +++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.3 @@ -1,90 +0,0 @@
     1.4 -// -*- c++ -*-
     1.5 -#include <iostream>
     1.6 -#include <fstream>
     1.7 -
     1.8 -#include <lemon/time_measure.h>
     1.9 -#include <lp_solver_base.h>
    1.10 -
    1.11 -using std::cout;
    1.12 -using std::endl;
    1.13 -using namespace lemon;
    1.14 -
    1.15 -/*
    1.16 -  On an 1537Mhz PC, the run times with 
    1.17 -  glpk are the following.
    1.18 -  for n=3,4, some secondes
    1.19 -  for n=5, 25 hours
    1.20 - */
    1.21 -
    1.22 -int main(int, char **) {
    1.23 -  const int n=4;
    1.24 -  const double row_sum=(1.0+n*n)*n/2;
    1.25 -  Timer ts;
    1.26 -  ts.reset();
    1.27 -  typedef LPGLPK LPSolver;
    1.28 -  typedef LPSolver::Col Col;
    1.29 -  LPSolver lp;
    1.30 -  typedef std::map<std::pair<int, int>, Col> Coords;
    1.31 -  Coords x;
    1.32 -  // we create a new variable for each entry 
    1.33 -  // of the magic square
    1.34 -  for (int i=1; i<=n; ++i) {
    1.35 -    for (int j=1; j<=n; ++j) { 
    1.36 -      Col col=lp.addCol();
    1.37 -      x[std::make_pair(i,j)]=col;
    1.38 -      lp.setColLowerBound(col, 1.0);
    1.39 -      lp.setColUpperBound(col, double(n*n));
    1.40 -    }
    1.41 -  }
    1.42 -  LPSolver::Expression expr3, expr4;
    1.43 -  for (int i=1; i<=n; ++i) {
    1.44 -    LPSolver::Expression expr1, expr2;
    1.45 -    for (int j=1; j<=n; ++j) {
    1.46 -      expr1+=x[std::make_pair(i, j)];
    1.47 -      expr2+=x[std::make_pair(j, i)];
    1.48 -    }
    1.49 -    // sum of rows and columns
    1.50 -    lp.addRow(expr1==row_sum);
    1.51 -    lp.addRow(expr2==row_sum);
    1.52 -    expr3+=x[std::make_pair(i, i)];
    1.53 -    expr4+=x[std::make_pair(i, (n+1)-i)];
    1.54 -  }
    1.55 -  // sum of the diagonal entries
    1.56 -  lp.addRow(expr3==row_sum);
    1.57 -  lp.addRow(expr4==row_sum);
    1.58 -  lp.solveSimplex();
    1.59 -  cout << "elapsed time: " << ts << endl;
    1.60 -  for (int i=1; i<=n; ++i) {
    1.61 -    for (int j=1; j<=n; ++j) { 
    1.62 -      cout << "x("<<i<<","<<j<<")="<<lp.getPrimal(x[std::make_pair(i,j)]) 
    1.63 -	   << endl;
    1.64 -    }
    1.65 -  }
    1.66 -  // we make new binary variables for each pair of 
    1.67 -  // entries of the square to achieve that 
    1.68 -  // the values of different entries are different
    1.69 -  lp.setMIP();
    1.70 -  for (Coords::const_iterator it=x.begin(); it!=x.end(); ++it) {
    1.71 -    Coords::const_iterator jt=it; ++jt;
    1.72 -    for(; jt!=x.end(); ++jt) {
    1.73 -      Col col1=(*it).second;
    1.74 -      Col col2=(*jt).second;
    1.75 -      Col col=lp.addCol();
    1.76 -      lp.setColLowerBound(col, 0.0);
    1.77 -      lp.setColUpperBound(col, 1.0);
    1.78 -      lp.addRow(double(-n*n+1.0)<=1.0*col2-1.0*col1-double(n*n)*col<=-1.0);
    1.79 -      lp.setColInt(col);
    1.80 -    }
    1.81 -  }
    1.82 -  cout << "elapsed time: " << ts << endl;
    1.83 -  lp.solveSimplex();
    1.84 -  // let's solve the integer problem
    1.85 -  lp.solveBandB();
    1.86 -  cout << "elapsed time: " << ts << endl;
    1.87 -  for (int i=1; i<=n; ++i) {
    1.88 -    for (int j=1; j<=n; ++j) { 
    1.89 -      cout << "x("<<i<<","<<j<<")="<<lp.getMIPPrimal(x[std::make_pair(i,j)]) 
    1.90 -	   << endl;
    1.91 -    }
    1.92 -  }
    1.93 -}