/* -*- C++ -*-

 *

 * This file is a part of LEMON, a generic C++ optimization library

 *

 * Copyright (C) 2003-2006

 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

 * (Egervary Research Group on Combinatorial Optimization, EGRES).

 *

 * Permission to use, modify and distribute this software is granted

 * provided that this copyright notice appears in all copies. For

 * precise terms see the accompanying LICENSE file.

 *

 * This software is provided "AS IS" with no warranty of any kind,

 * express or implied, and with no claim as to its suitability for any

 * purpose.

 *

 */

#include<iostream>

#include<lemon/lp_soplex.h>

#include <soplex/soplex.h>

///\file

///\brief Implementation of the LEMON-SOPLEX lp solver interface.

namespace lemon {

  LpSoplex::LpSoplex() : LpSolverBase() {

    rows.setIdHandler(relocateIdHandler);

    cols.setIdHandler(relocateIdHandler);

    soplex = new soplex::SoPlex;

    solved = false;

  }

  LpSoplex::~LpSoplex() {

    delete soplex;

  }

  LpSolverBase &LpSoplex::_newLp() {

    LpSoplex* newlp = new LpSoplex();

    return *newlp;

  }

  LpSolverBase &LpSoplex::_copyLp() {

    LpSoplex* newlp = new LpSoplex();

    ((soplex::SPxLP&)*(newlp->soplex)) = *soplex;

    return *newlp;

  }

  int LpSoplex::_addCol() {

    soplex::LPCol col;

    col.setLower(-soplex::infinity);

    col.setUpper(soplex::infinity);

    soplex->addCol(col);

    colNames.push_back(std::string());

    primal_value.push_back(0.0);

    solved = false;

    return soplex->nCols() - 1;

  }

  int LpSoplex::_addRow() {

    soplex::LPRow row;

    row.setLhs(-soplex::infinity);

    row.setRhs(soplex::infinity);

    soplex->addRow(row);

    dual_value.push_back(0.0);

    solved = false;

    return soplex->nRows() - 1;

  }

  void LpSoplex::_eraseCol(int i) {

    soplex->removeCol(i);

    colNames[i] = colNames.back();

    colNames.pop_back();

    primal_value[i] = primal_value.back();

    primal_value.pop_back();

    solved = false;

  }

  void LpSoplex::_eraseRow(int i) {

    soplex->removeRow(i);

    dual_value[i] = dual_value.back();

    dual_value.pop_back();

    solved = false;

  }

  void LpSoplex::_getColName(int col, std::string &name) {

    name = colNames[col]; 

  }

  void LpSoplex::_setColName(int col, const std::string &name) {

    colNames[col] = name; 

  }

  void LpSoplex::_setRowCoeffs(int i, ConstRowIterator b, ConstRowIterator e) {

    for (int j = 0; j < soplex->nCols(); ++j) {

      soplex->changeElement(i, j, 0.0);

    }

    for(ConstRowIterator it = b; it != e; ++it) {

      soplex->changeElement(i, it->first, it->second);

    }

    solved = false;

  }

  void LpSoplex::_getRowCoeffs(int i, RowIterator b) {

    const soplex::SVector& vec = soplex->rowVector(i);

    for (int k = 0; k < vec.size(); ++k) {

      *b = std::make_pair(vec.index(k), vec.value(k));

      ++b;

    }

  }

  void LpSoplex::_setColCoeffs(int j, ConstColIterator b, ConstColIterator e) {

    for (int i = 0; i < soplex->nRows(); ++i) {

      soplex->changeElement(i, j, 0.0);

    }

    for(ConstColIterator it = b; it != e; ++it) {

      soplex->changeElement(it->first, j, it->second);

    }

    solved = false;

  }

  void LpSoplex::_getColCoeffs(int i, ColIterator b) {

    const soplex::SVector& vec = soplex->colVector(i);

    for (int k = 0; k < vec.size(); ++k) {

      *b = std::make_pair(vec.index(k), vec.value(k));

      ++b;

    }

  }

  void LpSoplex::_setCoeff(int i, int j, Value value) {

    soplex->changeElement(i, j, value);

    solved = false;

  }

  LpSoplex::Value LpSoplex::_getCoeff(int i, int j) {

    return soplex->rowVector(i)[j];

  }

  void LpSoplex::_setColLowerBound(int i, Value value) {

    soplex->changeLower(i, value != -INF ? value : -soplex::infinity); 

    solved = false;

  }

  LpSoplex::Value LpSoplex::_getColLowerBound(int i) {

    double value = soplex->lower(i);

    return value != -soplex::infinity ? value : -INF;

  }

  void LpSoplex::_setColUpperBound(int i, Value value) {

    soplex->changeUpper(i, value != INF ? value : soplex::infinity); 

    solved = false;

  }

  LpSoplex::Value LpSoplex::_getColUpperBound(int i) {

    double value = soplex->upper(i);

    return value != soplex::infinity ? value : INF;

  }

  void LpSoplex::_setRowBounds(int i, Value lb, Value ub) {

    soplex->changeRange(i, lb != -INF ? lb : -soplex::infinity,

                        ub != INF ? ub : soplex::infinity);

    solved = false;

  }

  void LpSoplex::_getRowBounds(int i, Value &lower, Value &upper) {

    lower = soplex->lhs(i);

    if (lower == -soplex::infinity) lower = -INF;

    upper = soplex->rhs(i);

    if (upper == -soplex::infinity) upper = INF;

  }

  void LpSoplex::_setObjCoeff(int i, Value obj_coef) {

    soplex->changeObj(i, obj_coef);

    solved = false;

  }

  LpSoplex::Value LpSoplex::_getObjCoeff(int i) {

    return soplex->obj(i);

  }

  void LpSoplex::_clearObj() {

    for (int i = 0; i < soplex->nCols(); ++i) {

      soplex->changeObj(i, 0.0);

    }

    solved = false;

  }

  LpSoplex::SolveExitStatus LpSoplex::_solve() {

    soplex::SPxSolver::Status status = soplex->solve();

    soplex::Vector pv(primal_value.size(), &primal_value[0]);

    soplex->getPrimal(pv);

    soplex::Vector dv(dual_value.size(), &dual_value[0]);

    soplex->getDual(dv);

    switch (status) {

    case soplex::SPxSolver::OPTIMAL:

    case soplex::SPxSolver::INFEASIBLE:

    case soplex::SPxSolver::UNBOUNDED:

      solved = true;

      return SOLVED;

    default:

      return UNSOLVED;

    }

  }

  LpSoplex::Value LpSoplex::_getPrimal(int i) {

    return primal_value[i];

  }

  LpSoplex::Value LpSoplex::_getDual(int i) {

    return dual_value[i];

  }

  LpSoplex::Value LpSoplex::_getPrimalValue() {

    return soplex->objValue();

  }

  bool LpSoplex::_isBasicCol(int i) {

    return soplex->getBasisColStatus(i) == soplex::SPxSolver::BASIC;

  }  

  LpSoplex::SolutionStatus LpSoplex::_getPrimalStatus() {

    if (!solved) return UNDEFINED;

    switch (soplex->status()) {

    case soplex::SPxSolver::OPTIMAL:

      return OPTIMAL;

    case soplex::SPxSolver::UNBOUNDED:

      return INFINITE;

    case soplex::SPxSolver::INFEASIBLE:

      return INFEASIBLE;

    default:

      return UNDEFINED;

    }

  }

  LpSoplex::SolutionStatus LpSoplex::_getDualStatus() {

    if (!solved) return UNDEFINED;

    switch (soplex->status()) {

    case soplex::SPxSolver::OPTIMAL:

      return OPTIMAL;

    case soplex::SPxSolver::UNBOUNDED:

      return INFEASIBLE;

    default:

      return UNDEFINED;

    }

  }

  LpSoplex::ProblemTypes LpSoplex::_getProblemType() {

    if (!solved) return UNKNOWN;

    switch (soplex->status()) {

    case soplex::SPxSolver::OPTIMAL:

      return PRIMAL_DUAL_FEASIBLE;

    case soplex::SPxSolver::UNBOUNDED:

      return PRIMAL_FEASIBLE_DUAL_INFEASIBLE;

    default:

      return UNKNOWN;

    }

  }

  void LpSoplex::_setMax() {

    soplex->changeSense(soplex::SPxSolver::MAXIMIZE);

    solved = false;

  }

  void LpSoplex::_setMin() {

    soplex->changeSense(soplex::SPxSolver::MINIMIZE);

    solved = false;

  }

  bool LpSoplex::_isMax() {

    return soplex->spxSense() == soplex::SPxSolver::MAXIMIZE;

  }

} //namespace lemon