driver.cpp

// Copyright (C) 2005, International Business Machines
// Corporation and others.  All Rights Reserved.
// This code is licensed under the terms of the Eclipse Public License (EPL).

#include <cassert>
#include <iomanip>

// For Branch and bound
#include "CoinPragma.hpp"
#include "CbcModel.hpp"
#include "CbcStrategy.hpp"
#include "OsiClpSolverInterface.hpp"
// Preprocessing
#include "CglPreProcess.hpp"

#include "CoinTime.hpp"

//#############################################################################

/************************************************************************

This main program reads in an integer model from an mps file.
It then uses default strategy - just cuts at root node

************************************************************************/

int main(int argc, const char *argv[])
{

  OsiClpSolverInterface solver1;

  // Read in model using argv[1]
  // and assert that it is a clean model
  std::string mpsFileName;
#if defined(SAMPLEDIR)
  mpsFileName = SAMPLEDIR "/p0033.mps";
#else
  if (argc < 2) {
    fprintf(stderr, "Do not know where to find sample MPS files.\n");
    exit(1);
  }
#endif
  if (argc >= 2)
    mpsFileName = argv[1];
  int numMpsReadErrors = solver1.readMps(mpsFileName.c_str(), "");
  if (numMpsReadErrors != 0) {
    printf("%d errors reading MPS file\n", numMpsReadErrors);
    return numMpsReadErrors;
  }
  double time1 = CoinCpuTime();

  /* Options are:
     preprocess to do preprocessing
     time in minutes
     if 2 parameters and numeric taken as time
  */
  bool preProcess = false;
  double minutes = -1.0;
  int nGoodParam = 0;
  for (int iParam = 2; iParam < argc; iParam++) {
    if (!strcmp(argv[iParam], "preprocess")) {
      preProcess = true;
      nGoodParam++;
    } else if (!strcmp(argv[iParam], "time")) {
      if (iParam + 1 < argc && isdigit(argv[iParam + 1][0])) {
        minutes = atof(argv[iParam + 1]);
        if (minutes >= 0.0) {
          nGoodParam += 2;
          iParam++; // skip time
        }
      }
    }
  }
  if (nGoodParam == 0 && argc == 3 && isdigit(argv[2][0])) {
    // If time is given then stop after that number of minutes
    minutes = atof(argv[2]);
    if (minutes >= 0.0)
      nGoodParam = 1;
  }
  if (nGoodParam != argc - 2 && argc >= 2) {
    printf("Usage <file> [preprocess] [time <minutes>] or <file> <minutes>\n");
    exit(1);
  }
  // See if we want preprocessing
  OsiSolverInterface *solver2 = &solver1;
  CglPreProcess process;
  if (preProcess) {
    /* Do not try and produce equality cliques and
       do up to 5 passes */
    solver2 = process.preProcess(solver1, false, 5);
    if (!solver2) {
      printf("Pre-processing says infeasible\n");
      exit(2);
    }
    solver2->resolve();
  }
  CbcModel model(*solver2);
  // If time is given then stop after that number of minutes
  if (minutes >= 0.0) {
    std::cout << "Stopping after " << minutes << " minutes" << std::endl;
    model.setDblParam(CbcModel::CbcMaximumSeconds, 60.0 * minutes);
  }
  // Set strategy - below is == CbcStrategyDefault()
  CbcStrategyDefault strategy(true, 5, 0);
  model.setStrategy(strategy);
  // Do complete search

  model.branchAndBound();

  std::cout << mpsFileName << " took " << CoinCpuTime() - time1 << " seconds, "
            << model.getNodeCount() << " nodes with objective "
            << model.getObjValue()
            << (!model.status() ? " Finished" : " Not finished")
            << std::endl;

  // Print solution if finished - we can't get names from Osi!

  if (model.getMinimizationObjValue() < 1.0e50) {
    // post process
    OsiSolverInterface *solver;
    if (preProcess) {
      process.postProcess(*model.solver());
      // Solution now back in solver1
      solver = &solver1;
    } else {
      solver = model.solver();
    }
    int numberColumns = solver->getNumCols();

    const double *solution = solver->getColSolution();

    int iColumn;
    std::cout << std::setiosflags(std::ios::fixed | std::ios::showpoint) << std::setw(14);

    std::cout << "--------------------------------------" << std::endl;
    for (iColumn = 0; iColumn < numberColumns; iColumn++) {
      double value = solution[iColumn];
      if (fabs(value) > 1.0e-7 && solver->isInteger(iColumn))
        std::cout << std::setw(6) << iColumn << " " << value << std::endl;
    }
    std::cout << "--------------------------------------" << std::endl;

    std::cout << std::resetiosflags(std::ios::fixed | std::ios::showpoint | std::ios::scientific);
  }
  return 0;
}