diff -r ee5959aa4410 -r c280de819a73 src/work/marci/lp/magic_square.cc
--- a/src/work/marci/lp/magic_square.cc	Sun Apr 17 18:57:22 2005 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,90 +0,0 @@
-// -*- c++ -*-
-#include <iostream>
-#include <fstream>
-
-#include <lemon/time_measure.h>
-#include <lp_solver_base.h>
-
-using std::cout;
-using std::endl;
-using namespace lemon;
-
-/*
-  On an 1537Mhz PC, the run times with 
-  glpk are the following.
-  for n=3,4, some secondes
-  for n=5, 25 hours
- */
-
-int main(int, char **) {
-  const int n=4;
-  const double row_sum=(1.0+n*n)*n/2;
-  Timer ts;
-  ts.reset();
-  typedef LPGLPK LPSolver;
-  typedef LPSolver::Col Col;
-  LPSolver lp;
-  typedef std::map<std::pair<int, int>, Col> Coords;
-  Coords x;
-  // we create a new variable for each entry 
-  // of the magic square
-  for (int i=1; i<=n; ++i) {
-    for (int j=1; j<=n; ++j) { 
-      Col col=lp.addCol();
-      x[std::make_pair(i,j)]=col;
-      lp.setColLowerBound(col, 1.0);
-      lp.setColUpperBound(col, double(n*n));
-    }
-  }
-  LPSolver::Expression expr3, expr4;
-  for (int i=1; i<=n; ++i) {
-    LPSolver::Expression expr1, expr2;
-    for (int j=1; j<=n; ++j) {
-      expr1+=x[std::make_pair(i, j)];
-      expr2+=x[std::make_pair(j, i)];
-    }
-    // sum of rows and columns
-    lp.addRow(expr1==row_sum);
-    lp.addRow(expr2==row_sum);
-    expr3+=x[std::make_pair(i, i)];
-    expr4+=x[std::make_pair(i, (n+1)-i)];
-  }
-  // sum of the diagonal entries
-  lp.addRow(expr3==row_sum);
-  lp.addRow(expr4==row_sum);
-  lp.solveSimplex();
-  cout << "elapsed time: " << ts << endl;
-  for (int i=1; i<=n; ++i) {
-    for (int j=1; j<=n; ++j) { 
-      cout << "x("<<i<<","<<j<<")="<<lp.getPrimal(x[std::make_pair(i,j)]) 
-	   << endl;
-    }
-  }
-  // we make new binary variables for each pair of 
-  // entries of the square to achieve that 
-  // the values of different entries are different
-  lp.setMIP();
-  for (Coords::const_iterator it=x.begin(); it!=x.end(); ++it) {
-    Coords::const_iterator jt=it; ++jt;
-    for(; jt!=x.end(); ++jt) {
-      Col col1=(*it).second;
-      Col col2=(*jt).second;
-      Col col=lp.addCol();
-      lp.setColLowerBound(col, 0.0);
-      lp.setColUpperBound(col, 1.0);
-      lp.addRow(double(-n*n+1.0)<=1.0*col2-1.0*col1-double(n*n)*col<=-1.0);
-      lp.setColInt(col);
-    }
-  }
-  cout << "elapsed time: " << ts << endl;
-  lp.solveSimplex();
-  // let's solve the integer problem
-  lp.solveBandB();
-  cout << "elapsed time: " << ts << endl;
-  for (int i=1; i<=n; ++i) {
-    for (int j=1; j<=n; ++j) { 
-      cout << "x("<<i<<","<<j<<")="<<lp.getMIPPrimal(x[std::make_pair(i,j)]) 
-	   << endl;
-    }
-  }
-}