예제 #1
0
void seleciona_propagandas(int n, double C, double V[N], double P[N], double w[N][N], int S[N], double *UpperBound, long maxtime) {
	GRBVar y[N][N];
	GRBVar x[N];

	int seed=0;
	GRBEnv env = GRBEnv();
	GRBModel model = GRBModel(env);
	model.getEnv().set(GRB_IntParam_Seed, seed);
	model.set(GRB_StringAttr_ModelName, "Alocacao Propaganda"); // prob. name
	model.set(GRB_IntAttr_ModelSense, GRB_MAXIMIZE); // is a minimization problem  

	for(int i = 0; i < n; i++) {
		char name[100];
		sprintf(name,"x_%d",i);
		x[i] = model.addVar(0.0, 1.0, V[i],GRB_BINARY, name); 
	}

	for( int i = 0; i < n; i++) {

		for(int j = i+1; j < n; j++) {
			char name[100];
			sprintf(name,"y_%d_%d",i, j);
			y[i][j] = model.addVar(0.0, 1.0, w[i][j], GRB_BINARY, name); 
		}
	}
	
	model.update();
	
	GRBLinExpr expr;
	for(int i = 0; i < n; i++) {
		expr += (x[i] * P[i]);
	}
	model.addConstr(expr <= C);
	model.update();
	
	for(int i = 0; i < n; i++) {
		
		for(int j =i+1; j < n; j++) {
			model.addConstr(y[i][j] <= x[i]);
			model.addConstr(y[i][j] <= x[j]);
			model.addConstr(x[i] + x[j] <= (y[i][j] + 1));
		}
	}
	model.update();
	
	model.write("model.lp");
	
	model.optimize();
	
	*UpperBound = model.get(GRB_DoubleAttr_ObjVal);
	
}
int monitoramento_em_grafo_bipartido( ListGraph &g, NodeName &vname, ListGraph::NodeMap<double> &custo, ListGraph::NodeMap<int> &solucao)
{
  int seed=0;
  GRBEnv env = GRBEnv();
  GRBModel model = GRBModel(env);
  model.getEnv().set(GRB_IntParam_Seed, seed);
  model.set(GRB_StringAttr_ModelName, "Monitoramento em Grafo Bipartido"); // prob. name
  model.set(GRB_IntAttr_ModelSense, GRB_MINIMIZE); // is a minimization problem
  // ------------------------------------------------------
  // Construa o modelo daqui para baixo
  // ------------------------------------------------------

  // Exemplos de como voce pode declarar variaveis indexadas nos vertices ou nas arestas.
  // Nao necessariamente voce precisa dos dois tipos
  // ListGraph::NodeMap<GRBVar> x(g); // variables for each node
  // ListGraph::EdgeMap<GRBVar> y(g); // variables for each edge
  ListGraph::NodeMap<GRBVar> x(g); // variables for each node
  ListGraph::EdgeMap<GRBVar> y(g); // variables for each edge
  int name = 0;
  char namme[100];
  for(ListGraph::NodeIt v(g); v != INVALID; ++v) {
    sprintf(namme,"PC_%s",vname[v].c_str());
    x[v] = model.addVar(0.0, 1.0, custo[v],GRB_CONTINUOUS,namme); }
  model.update();
  try {
    for(ListGraph::EdgeIt e(g); e != INVALID; ++e) {
      //Para cada aresta, um dos lados e 1
      GRBLinExpr expr;
      expr += x[g.u(e)];
      expr += x[g.v(e)];
      model.addConstr(expr >= 1);
    }
    model.update();
    // ------------------------------------------------------
    // Construa o modelo daqui para cima
    // ------------------------------------------------------
    //model.write("model.lp"); system("cat model.lp");
    model.optimize();
    for (ListGraph::NodeIt v(g); v!=INVALID; ++v) {
      if (x[v].get(GRB_DoubleAttr_X)>1-EPS) solucao[v] = 1;
      else solucao[v] = 0;
      //solucao[v] = 1;
    }
    return(1);

  } catch (...) {cout << "Error during callback..." << endl; return(0);}
}
예제 #3
0
void solve(const Instance &inst, bool print_inst = false, bool pyout = false) {
    Arcflow afg(inst);
    char vtype = inst.vtype;
    GRBEnv* env = new GRBEnv();
    GRBModel model = GRBModel(*env);
    model.set(GRB_StringAttr_ModelName, "flow");

    model.getEnv().set(GRB_IntParam_OutputFlag, 1);
    model.getEnv().set(GRB_IntParam_Threads, 1);
    model.getEnv().set(GRB_IntParam_Presolve, 1);
    // model.getEnv().set(GRB_IntParam_Method, 0);
    model.getEnv().set(GRB_IntParam_Method, 2);
    model.getEnv().set(GRB_IntParam_MIPFocus, 1);
    // model.getEnv().set(GRB_IntParam_RINS, 1);
    model.getEnv().set(GRB_DoubleParam_Heuristics, 1);
    model.getEnv().set(GRB_DoubleParam_MIPGap, 0);
    model.getEnv().set(GRB_DoubleParam_MIPGapAbs, 1-1e-5);
    // model.getEnv().set(GRB_DoubleParam_ImproveStartTime, 60);
    // model.getEnv().set(GRB_DoubleParam_ImproveStartGap, 1);

    vector<Arc> As(afg.A);
    sort(all(As));
    map<Arc, GRBVar> va;
    int lastv = afg.Ts[0]-1;
    for (int i = 0; i < inst.nbtypes; i++) {
        lastv = min(lastv, afg.Ts[i]-1);
    }
    for (int i = 0; i < 3; i++) {
        for (const Arc &a : As) {
            if (i == 1 && a.u != afg.S) {
                continue;
            }
            if (i == 2 && a.v <= lastv) {
                continue;
            }
            if (i == 0 && (a.u == afg.S || a.v > lastv)) {
                continue;
            }

            if (a.label == afg.LOSS || inst.relax_domains) {
                va[a] = model.addVar(
                    0.0, inst.n, 0, vtype);
            } else {
                va[a] = model.addVar(
                    0.0, inst.items[a.label].demand, 0, vtype);
            }
        }
    }
    model.update();

    for (int i = 0; i < inst.nbtypes; i++) {
        GRBVar &feedback = va[Arc(afg.Ts[i], afg.S, afg.LOSS)];
        feedback.set(GRB_DoubleAttr_Obj, inst.Cs[i]);
        if (inst.Qs[i] >= 0) {
            feedback.set(GRB_DoubleAttr_UB, inst.Qs[i]);
        }
    }

    vector<vector<Arc>> Al(inst.nsizes);
    vector<vector<Arc>> in(afg.NV);
    vector<vector<Arc>> out(afg.NV);

    for (const Arc &a : As) {
        if (a.label != afg.LOSS) {
            Al[a.label].push_back(a);
        }
        out[a.u].push_back(a);
        in[a.v].push_back(a);
    }

    for (int i = 0; i < inst.m; i++) {
        GRBLinExpr lin = 0;
        for (int it = 0; it < inst.nsizes; it++) {
            if (inst.items[it].type == i) {
                for (const Arc &a : Al[it]) {
                    lin += va[a];
                }
            }
        }
        if (inst.ctypes[i] == '>' || inst.relax_domains) {
            model.addConstr(lin >= inst.demands[i]);
        } else {
            model.addConstr(lin == inst.demands[i]);
        }
    }

    for (int u = 0; u < afg.NV; u++) {
        GRBLinExpr lin = 0;
        for (const Arc &a : in[u]) {
            lin += va[a];
        }
        for (const Arc &a : out[u]) {
            lin -= va[a];
        }
        model.addConstr(lin == 0);
    }

    Al.clear();
    in.clear();
    out.clear();

    double pre = TIMEDIF(afg.tstart);
    model.optimize();
    printf("Preprocessing time: %.2f seconds\n", pre);
    double tg = model.get(GRB_DoubleAttr_Runtime);
    printf("Gurobi run time: %.2f seconds\n", tg);
    printf("Total run time: %.2f seconds\n", tg+pre);

    if (inst.vtype == 'I') {
        map<Arc, int> flow;
        for (const auto &a : va) {
            double x = a.second.get(GRB_DoubleAttr_X);
            int rx = static_cast<int>(round(x));
            assert(x - rx <= EPS);
            if (rx > 0) {
                int u = a.first.u;
                int v = a.first.v;
                int lbl = a.first.label;
                Arc a(u, v, lbl);
                flow[a] = rx;
            }
        }
        ArcflowSol solution(inst, flow, afg.S, afg.Ts, afg.LOSS, true);
        solution.print_solution(print_inst, pyout);
    }
    free(env);
}
예제 #4
0
int main(int argc, char *argv[]) 
{
  int k,found;
  Digraph g;  // graph declaration
  string digraph_kpaths_filename, source_node_name, target_node_name;
  DiNodeName vname(g);  // name of graph nodes
  Digraph::NodeMap<double> px(g),py(g);  // xy-coodinates for each node
  Digraph::NodeMap<int> vcolor(g);// color of nodes
  Digraph::ArcMap<int> ecolor(g); // color of edges
  ArcWeight lpvar(g);    // used to obtain the contents of the LP variables
  ArcWeight weight(g);   // edge weights
  Digraph::ArcMap<GRBVar> x(g); // binary variables for each arc
  vector <DiNode> V;
  DiNode source,target;
  int seed=0;
  srand48(1);

  // uncomment one of these lines to change default pdf reader, or insert new one
  //set_pdfreader("open");    // pdf reader for Mac OS X
  //set_pdfreader("xpdf");    // pdf reader for Linux
  set_pdfreader("evince");  // pdf reader for Linux
  //set_pdfreader("open -a Skim.app");
  // double cutoff;   // used to prune non promissing branches (of the B&B tree)
  if (argc!=5) {cout<<endl<<"Usage: "<< argv[0]<<"  <digraph_kpaths_filename>  <source_node_name>  <target_node_name>  <k>"<< endl << endl;
    cout << "Example:      " << argv[0] << " digr_triang_sparse_100 12 50 5" << endl << endl;
    exit(0);}

  digraph_kpaths_filename = argv[1];
  source_node_name = argv[2];
  target_node_name = argv[3];
  k = atoi(argv[4]);

  GRBEnv env = GRBEnv();
  GRBModel model = GRBModel(env);
  model.getEnv().set(GRB_IntParam_Seed, seed);
  model.set(GRB_StringAttr_ModelName, "Oriented k-Paths with GUROBI"); // prob. name
  model.set(GRB_IntAttr_ModelSense, GRB_MINIMIZE); // is a minimization problem

  ReadListDigraph(digraph_kpaths_filename,g,vname,weight,px,py,0);
  found=0;
  for (DiNodeIt v(g);v!=INVALID;++v)
    if(vname[v]==source_node_name){source=v;found=1;break;}
  if (!found) {cout<<"Could not find source node "<<source_node_name<<endl;exit(0);}
  found=0;
  for (DiNodeIt v(g);v!=INVALID;++v)
    if(vname[v]==target_node_name){target=v;found=1;break;}
  if (!found) {cout<<"Could not find target node "<<target_node_name<<endl;exit(0);}
    
  kPaths_Instance T(g,vname,px,py,weight,source,target,k);
  
  //for (DiNodeIt v(g);v!=INVALID;++v){ if(v==T.V[0])vcolor[v]=RED; else vcolor[v]=BLUE;}
  //for (int i=1;i<T.nt;i++) vcolor[T.V[i]] = MAGENTA;
  //for (ArcIt e(g); e != INVALID; ++e) ecolor[e] = BLUE;
  //ViewListDigraph(g,vname,px,py,vcolor,ecolor,"Triangulated graph");
  
  // Generate the binary variables and the objective function
  // Add one binary variable for each edge and set its cost in the objective function
  for (Digraph::ArcIt e(g); e != INVALID; ++e) {
    char name[100];
    sprintf(name,"X_%s_%s",vname[g.source(e)].c_str(),vname[g.target(e)].c_str());
    x[e] = model.addVar(0.0, 1.0, weight[e],GRB_CONTINUOUS,name); }
  model.update(); // run update to use model inserted variables
  try {
    //if (time_limit >= 0) model.getEnv().set(GRB_DoubleParam_TimeLimit,time_limit);
    //model.getEnv().set(GRB_DoubleParam_ImproveStartTime,10); //try better sol. aft. 10s
    // if (cutoff > 0) model.getEnv().set(GRB_DoubleParam_Cutoff, cutoff );
    //model.write("model.lp"); system("cat model.lp");

    // Add degree constraint for each node (sum of solution edges incident to a node is 2)
    for (Digraph::NodeIt v(g); v!=INVALID; ++v) {
      GRBLinExpr exprin, exprout;
      for (Digraph::InArcIt e(g,v); e != INVALID; ++e) exprin += x[e];
      for (Digraph::OutArcIt e(g,v); e != INVALID; ++e) exprout += x[e];

      if (v==source)      model.addConstr(exprout - exprin == k );
      else if (v==target) model.addConstr(exprin - exprout == k );
      else                model.addConstr(exprin - exprout == 0 );
    }

    model.optimize();

    double soma=0.0;
    for (DiNodeIt v(g);v!=INVALID;++v) vcolor[v]=BLUE; // all nodes BLUE
    vcolor[source]=RED; // change the colors of the source node
    vcolor[target]=RED; // and the target node to RED
    for (Digraph::ArcIt e(g); e!=INVALID; ++e) {
      lpvar[e] = x[e].get(GRB_DoubleAttr_X);
      if (lpvar[e] > 1.0 - EPS) soma += weight[e];
    }
    cout << "kPaths Tree Value = " << soma << endl;

    //-----------------------------------------------------------------
    // By Lucas Prado Melo: coloring paths by bfs
    bool ok = true;
    for(int i=0; i < k && ok; i++) {
      queue<DiNode> q;
      Digraph::NodeMap<Arc> pre(g, INVALID);
      q.push(source);
      while (!q.empty()) {
        DiNode cur = q.front();
        q.pop();
        for(Digraph::OutArcIt e(g, cur); e!=INVALID; ++e) {
          DiNode nxt = g.runningNode(e);
          if (pre[nxt] == INVALID && ecolor[e] == NOCOLOR && lpvar[e] > 1.0 - EPS) {
            pre[nxt] = e;
            q.push(nxt);
          }
        }
      }
      if (pre[target] == INVALID) ok = false;
      else {
        DiNode x = target;
        while (x != source) {
          ecolor[pre[x]] = 3+i%6; // use colors 3(RED) to 8(CYAN), see myutils.h
          x = g.oppositeNode(x, pre[x]);
        }
      }
    }
    if (!ok) {cout << "Nao eh possivel encontrar os " << k << " caminhos!" << endl;}
    for(Digraph::ArcIt e(g); e!=INVALID; ++e) {
      if (lpvar[e] > 1.0 - EPS && ecolor[e] == NOCOLOR ) {
        cout << "Alguma(s) aresta(s) nao pertencem a qualquer caminho!" << endl;
        break;
      }
    }
    for(Digraph::ArcIt e(g); e!=INVALID; ++e) {
      if (lpvar[e] < 1.0-EPS && lpvar[e] > EPS) {
        ecolor[e] = GRAY;
      }
    }
    for(Digraph::ArcIt e(g); e!=INVALID; ++e) {
      if (lpvar[e] < 1.0-EPS && lpvar[e] > EPS) {
        cout << "Alguma(s) aresta(s) possuem valor fracionario! (marcadas com cor cinza claro)" << endl;
        break;
      }
    }
    //-----------------------------------------------------------------


    cout << "kPaths Tree Value = " << soma << endl;
    ViewListDigraph(g,vname,px,py,vcolor,ecolor,
	"minimum kPaths cost in graph with "+IntToString(T.nnodes)+
	" nodes and "+IntToString(k)+" paths: "+DoubleToString(soma));
  } catch (...) {cout << "Error during callback..." << endl; }
  return 0;
}
예제 #5
0
int main(int argc,char *argv[]) {
  srand48(1);
  if (argc!=2) {cout<<endl<<"Usage: "<< argv[0]<<"  <filename>"<< endl << endl;
    cout << "Example:      " << argv[0] << " arq1.in" << endl << endl; exit(0);}
	
  ifstream ifile;
  ifile.open(argv[1]);  if (!ifile) return(false);  

  int n, m;
  ifile >> n; ifile >> m;
  vector<double> jobsize(n);
  vector<double> machinespeed(m);
  for(int i=0; i<n; i++) ifile >> jobsize[i];
  for(int i=0; i<m; i++) ifile >> machinespeed[i];
  ifile.close();

  cout << endl;
  cout << "Numero de tarefas: " << n << endl;
  cout << "Tamanho das tarefas" << endl;
  for(int i=0; i<n; i++)
    cout << "T_" << i << ": " << jobsize[i] << endl;
  cout << "Velocidade das maquinas" << endl;
  for(int i=0; i<m; i++)
    cout << "M_" << i << ": " << machinespeed[i] << endl;
  cout << endl << endl;
  
  try {
/*--------------------------------------------------------------------------------- */	
/*--------------------------- ALTERE DAQUI PARA ABAIXO ---------------------------- */
/*--------------------------------------------------------------------------------- */	

    // Voce deve atualizar esta variavel com valores 0 e 1 de tal forma que
    // tarefa_maquina[i][j] = 1 SE_E_SOMENTE_SE a tarefa i foi escalonada na maq. j
    vector<vector<int> > tarefa_maquina(n, vector<int>(m));

    // mais abaixo eh feito um escalonamento aleatorio.
    // Nao se esqueca de alterar a geracao do escalonamento aleatorio para o
    // escalonamento obtido pelo seu programa linear inteiro


    // cabecalho comum para os programas lineares (descomente)
     int seed=0;
     GRBEnv env = GRBEnv();
     GRBModel model = GRBModel(env);
     model.getEnv().set(GRB_IntParam_Seed, seed);
     model.set(GRB_StringAttr_ModelName, "Escalonamento de Tarefas"); // prob. name
     model.set(GRB_IntAttr_ModelSense, GRB_MINIMIZE); // is a minimization problem  

	GRBVar min;
	
	GRBVar x[m][n];

	min = model.addVar(0, 30000, 1 , GRB_CONTINUOUS, "min");

	
	int i,j;
	for(i=0;i<m;i++){
		for(j=0;j<n;j++) {
			char name[100];
			sprintf(name,"I%dM%d",i,j);
			x[i][j] = model.addVar(0, 1, 0 , GRB_BINARY, name);	
		}
	}
		
	model.update();

	//cada tarefa em 1 máquina
	
	for (int i=0; i<n; i++){
		GRBLinExpr sum2;
      		for (int j=0; j<m; j++){
			sum2= sum2 + x[j][i];
		}
		model.addConstr(sum2 == 1);
	}	

	//min eh pior caso
	for(int j=0; j<m; j++){
		GRBLinExpr sum3;
		for (i=0; i<n ; i++) {
			sum3 = sum3 + jobsize[i]*x[j][i]/ machinespeed[j];
		}
		model.addConstr(min >= sum3);
	}

	model.update();
	model.write("model.lp");
	system("cat model.lp");

	model.optimize();
	// Verifica se obteve solucao otima
	if (model.get(GRB_IntAttr_Status) != GRB_OPTIMAL) {
       cout << "Erro, sistema impossivel" << endl;
       exit(1);
	}
    for (int i=0; i<n; i++){
      for (int j=0; j<m; j++){
	if(x[j][i].get(GRB_DoubleAttr_X)>0.999)
		tarefa_maquina[i][j] = 1; 
	else
		tarefa_maquina[i][j] = 0; 
	}
	}
 

	  
/*--------------------------------------------------------------------------------- */	
/*--------------------------- ALTERE DAQUI PARA CIMA ------------------------------ */
/*--------------------------------------------------------------------------------- */	

    cout << "\n\n";
      double makespan=0;
      cout << "Escalonamento obtido das tarefas nas maquinas\n";
      cout << "Notacao para tarefas : T_id(tamanho_original)\n";
      cout << "Notacao para maquinas: M_id(velocidade)\n\n";
      
      for (int j=0; j<m; j++) {
	double tmaq=0.0;
	cout << "M_"<<j<<"("<< machinespeed[j] << ") : ";
	for(int i=0; i<n; i++) {
	  if (tarefa_maquina[i][j] == 1) {
	    cout << "T_" << i << "(" << jobsize[i] << ") ";
	    tmaq += jobsize[i] / machinespeed[j];
	  }
	}
	cout << endl << "Tempo gasto pela maquina M_" <<j << ": " << tmaq << endl<<endl;
	if (tmaq>makespan) makespan = tmaq;
      }
      cout << "\nTempo para completar todas as tarefas: " << makespan << "s\n\n";
      //  } else  cout << "No solution" << "\n";
  }
  // catch (GRBException e) {
  //   cout << "Error code = " << e.getErrorCode() << endl;
  //   cout << e.getMessage() << endl;
  // }
  catch (...) {
    cout << "Exception during optimization" << endl;
  }
  return 0;
}
예제 #6
0
// ATENÇÃO: Não modifique a assinatura deste método.
bool brach_and_bound999999(TSP_Data_R &tsp, const vector<DNode> &terminais, const vector<DNode> &postos,
                           const DNode source,
                           int delta, int maxTime, vector<DNode> &sol, double &lbound){
    // Converte o TSP direcionado para um nao direcionado com duas arestas
    ListGraph graph;
    EdgeValueMap weights(graph);

    // Adiciona os nos
    for (ListDigraph::NodeIt u(tsp.g); u!=INVALID; ++u)
    {
        Node v = graph.addNode();
    }

    // Adiciona as arestas
    for (ListDigraph::ArcIt ait(tsp.g); ait!=INVALID; ++ait)
    {
        // pega os dois nos incidentes
        Arc a(ait);
        DNode u = tsp.g.source(a);
        DNode v = tsp.g.target(a);

        // cria a mesma aresta no grafo não direcionado
        Node gu = graph.nodeFromId(tsp.g.id(u));
        Node gv = graph.nodeFromId(tsp.g.id(v));

        // insere a aresta no grafo nao direcionado
        Edge e = graph.addEdge(gu, gv);
        
        // Atribui pesos as arestas
        weights[e] = tsp.weight[a];
    }

    NodeStringMap nodename(graph);
    NodePosMap posicaox(graph);
    NodePosMap posicaoy(graph);

    TSP_Data utsp(graph, nodename, posicaox, posicaoy, weights);

    // utiliza o convertido
    ListGraph::EdgeMap<GRBVar> x(graph);
    GRBEnv env = GRBEnv();
    GRBModel model = GRBModel(env);

    // TODO: [Opcional] Comente a linha abaixo caso não queira inserir cortes durante a execução do B&B
    model.getEnv().set(GRB_IntParam_LazyConstraints, 1);

    model.getEnv().set(GRB_IntParam_Seed, 0);
    model.set(GRB_StringAttr_ModelName, "TSPR - TSP with Refueling"); // name to the problem
    model.set(GRB_IntAttr_ModelSense, GRB_MINIMIZE); // is a minimization problem

    // Add one binary variable for each arc and also sets its cost in the objective function
    for (EdgeIt e(utsp.g); e!=INVALID; ++e) {
        char name[100];
        
        Edge edge(e);
        unsigned uid = utsp.g.id(utsp.g.u(edge));
        unsigned vid = utsp.g.id(utsp.g.v(edge));

        sprintf(name,"x_%s_%s",tsp.vname[tsp.g.nodeFromId(uid)].c_str(),tsp.vname[tsp.g.nodeFromId(vid)].c_str());
        x[e] = model.addVar(0.0, 1.0, utsp.weight[e],GRB_BINARY,name);
    }
    model.update(); // run update to use model inserted variables

    // converte os terminais e os postos
    vector<Node> uterminais;
    for (auto t : terminais)
    {
        unsigned tid = tsp.g.id(t);
        uterminais.push_back(utsp.g.nodeFromId(tid));
    }

    NodeBoolMap upostos(utsp.g, false);
    for (auto p: postos)
    {
        unsigned pid = tsp.g.id(p);
        // upostos.push_back(utsp.g.nodeFromId(pid));
        upostos[utsp.g.nodeFromId(pid)] = true;
    }

    // Adicione restrições abaixo

    // (1) Nós terminais devem ser visitados exatamente uma vez
    for (auto v : uterminais) {
        GRBLinExpr expr = 0;
        for (IncEdgeIt e(utsp.g,v); e!=INVALID; ++e){
            expr += x[e];
        }
        model.addConstr(expr == 2 );
    }

    // (3) Nó source sempre presente no início do caminho
    Node usource = utsp.g.nodeFromId(tsp.g.id(source));
    GRBLinExpr expr = 0;
    for (IncEdgeIt e(utsp.g,usource); e!=INVALID; ++e){
        expr += x[e];
    }
    model.addConstr(expr >= 1 );

    try {
        model.update(); // Process any pending model modifications.
        //if (maxTime >= 0) model.getEnv().set(GRB_DoubleParam_TimeLimit,maxTime);

        subtourelim cb = subtourelim(utsp , x, usource, upostos, delta);
        model.setCallback(&cb);

        // TODO: [Opcional] Pode-se utilizar o valor de uma solução heurística p/ acelerar o algoritmo B&B (cutoff value).
        //cutoff = tsp.BestCircuitValue-MY_EPS;
        double cutoff = 0.0;
        if (cutoff > MY_EPS) model.getEnv().set(GRB_DoubleParam_Cutoff, cutoff );
        model.update(); // Process any pending model modifications.
        model.optimize();

        // Obtém o status da otimização
        int status = model.get(GRB_IntAttr_Status);
        if(status == GRB_INFEASIBLE || status == GRB_INF_OR_UNBD){
            cout << "Modelo inviavel ou unbounded." << endl;
            return false;
        }

        // Limitante inferior e superior do modelo
        //lbound = model.get(GRB_DoubleAttr_ObjBoundC);

        if( model.get(GRB_IntAttr_SolCount) <= 0 ){
            cout << "Modelo nao encontrou nenhuma solucao viavel no tempo. LowerBound = " << lbound << endl;
            return false;
        }
        else if (status == GRB_OPTIMAL){
            if(verbose) cout << "O modelo foi resolvido ate a otimalidade." << endl;
        }
        else {
            if(verbose) cout << "O modelo encontrou uma solucao sub-otima (i.e. nao ha garantia de otimalidade)." << endl;
        }

        double custo_solucao = model.get(GRB_DoubleAttr_ObjVal);
        
        int uncovered=0;
        EdgeBoolMap cover(utsp.g, false);
        for (EdgeIt e(utsp.g); e!=INVALID; ++e)
        {
            if (BinaryIsOne(x[e].get(GRB_DoubleAttr_X)))
            {
                cover[e] = true;
                uncovered++;
            }
        }
        sol.push_back(tsp.g.nodeFromId(utsp.g.id(usource)));        
        convertSol(x, sol, tsp, utsp, usource, cover, uncovered);

        // Calculo manual do custo da solução (deve ser igual ao ObjVal do Gurobi).
        double soma=0.0;
        ArcName aname(tsp.g);
        vector<Arc> edgesSol;
        ArcColorMap acolor(tsp.g);
        // if( verbose ) cout << "####### " << endl << "Edges of Solution (B&B):" << endl;
        // for (EdgeIt e(utsp.g); e!=INVALID; ++e){
        //     if (BinaryIsOne(x[e].get(GRB_DoubleAttr_X))){ // Note que se este método serve para variáveis binárias, p/ inteiras terá de usar outro método.
        //         soma += utsp.weight[e];
        //         edgesSol.push_back(tsp.g.arcFromId(utsp.g.id(e)));
        //         if( verbose) cout << "(" << tsp.vname[tsp.g.nodeFromId(utsp.g.id(utsp.g.u(e)))] << "," << tsp.vname[tsp.g.nodeFromId(utsp.g.id(utsp.g.v(e)))] << ")" << endl;
        //         acolor[tsp.g.arcFromId(utsp.g.id(e))] = BLUE;
        //     }
        // }
        // if( verbose ) cout << "####### " << endl;
        if( verbose ) cout << "####### " << endl << "Edges of Solution (B&B):" << endl;
        DNode u = sol[0];
        for (int i=1; i<sol.size(); i++) 
        {
            DNode v = sol[i];
            soma += tsp.AdjMatD.Cost(u,v);
            if ( verbose ) cout << "(" << tsp.vname[u] << "," << tsp.vname[v] << ")" << endl;
            u = v;
        }
        if( verbose ) cout << "####### " << endl;

        if( verbose ) cout << "Custo calculado pelo B&B = "<< soma << " / " << custo_solucao << endl;
        if( verbose ){
            cout << "Caminho encontrado a partir do vértice de origem (" << tsp.vname[source] << "): ";
            for(auto node : sol){
                cout << tsp.vname[node] << " ";
            } // Obs: O caminho é gerado a partir do nó source, se o conjunto de arestas retornado pelo B&B for desconexo, o caminho retornado por 'path_search' será incompleto.
            cout << endl << "Custo calculado da solucao (caminho a partir do no origem) = " << solutionCost(tsp, sol) << endl;
            ostringstream out;
            out << "TSP with Refueling B&B, cost= " << custo_solucao;
            ViewListDigraph(tsp.g, tsp.vname, tsp.posx, tsp.posy, tsp.vcolor, acolor, out.str());
        }
        return true;
    }
    catch(GRBException e) {
        cerr << "Gurobi exception has been thrown." << endl;
        cerr << "Error code = " << e.getErrorCode() << endl;
        cerr << e.getMessage();
    }
    catch (...) {
        cout << "Model is infeasible"  << endl;
        return false;
    }
    return false;
}
예제 #7
0
int main(int argc, char *argv[])
{
	GRBEnv* env = 0;
	GRBVar* covered = 0; // we want to maximize demand covered
	GRBVar* facility = 0;
	int max_n_Facilities = 10;

	try
	{
		const string filename = "/Users/katarzyna/Dropbox/matlab/2015-05 PKITS/aij_matrix.txt";

		std::vector<std::vector<long int> > aij_matrix;
		readMatrix_aij(filename, aij_matrix);

		std::cout << "matrix size "<< aij_matrix.size() <<" x "<< aij_matrix[0].size() << std::endl;

		// Model
		env = new GRBEnv();
		GRBModel model = GRBModel(*env);
		model.set(GRB_StringAttr_ModelName, "minimize number of facilities");

		// Demand coverage decision variable, covered[i] == 1 if demand is covered
		covered = model.addVars(aij_matrix.size(), GRB_BINARY);
		model.update();

		// Facility open variables: facility[j] == 1 if facility j is open.
		facility = model.addVars(aij_matrix.size(), GRB_BINARY);
		model.update();


		// Set the objective to maximize the demand covered
		for (unsigned int i = 0; i < aij_matrix.size(); ++i)
		{
			ostringstream vname;
			vname << "Demand " << i;
			covered[i].set(GRB_DoubleAttr_Obj, 1);
			covered[i].set(GRB_StringAttr_VarName, vname.str());
		}

		for (unsigned int i = 0; i < aij_matrix.size(); ++i)
		{
			ostringstream vname;
			vname << "Open " << i;
			facility[i].set(GRB_DoubleAttr_Obj, 0);
			facility[i].set(GRB_StringAttr_VarName, vname.str());
		}

		// The objective is to maximize the total demand covered
		model.set(GRB_IntAttr_ModelSense, 0);

		// Update model
		model.update();

		// Constraints

		// If demand i is covered by at least one station, then covered[i] == 1
		for (unsigned int i = 0; i < aij_matrix.size(); ++i)
		{
			GRBLinExpr demand_is_covered = 0;
			for (unsigned int j = 0; j < aij_matrix.size(); ++j)
			{
				demand_is_covered += aij_matrix[i][j] * facility[j];
			}
			ostringstream cname;
			cname << "Demand_i_is_covered " << i;
			model.addConstr(demand_is_covered >= covered[i], cname.str());
		}

		// We allow no more than n facilities
		GRBLinExpr facilities_to_open = 0;
		for (unsigned int j = 0; j < aij_matrix.size(); ++j) {
			facilities_to_open += facility[j];
		}

		ostringstream vname;
		vname << "Max facility... ";
		model.addConstr(facilities_to_open <= max_n_Facilities);

		model.update();

		// Solve
		model.optimize();

		model.write("/Users/katarzyna/Dropbox/matlab/2015-05 PKITS/output.lp");

		// Print solution
		cout << "\nTOTAL COSTS: " << model.get(GRB_DoubleAttr_ObjVal) << endl;
		cout << "SOLUTION:" << endl;
		int sum_d = 0;
		for (unsigned int i = 0; i < aij_matrix.size(); ++i)
		{
			if (covered[i].get(GRB_DoubleAttr_X) == 1.0)
			{
				//cout << "Demand " << i << " covered." << endl;
				sum_d += 1;
			}
		}

		int sum_f = 0;
		for (unsigned int i = 0; i < aij_matrix.size(); ++i)
		{
			if (facility[i].get(GRB_DoubleAttr_X) == 1.0)
			{
				cout << "Facility " << i << " is opened." << endl;
				sum_f += 1;
			}
		}
		cout << sum_f << " facilities is open." << endl;
		cout << sum_d << " customers is covered." << endl;


	} catch (GRBException e)
	{
		cout << "Error code = " << e.getErrorCode() << endl;
		cout << e.getMessage() << endl;
	} catch (...)
	{
		cout << "Exception during optimization" << endl;
	}
}
예제 #8
0
int main(int argc,char *argv[]) {
  srand48(1);
  if (argc!=2) {cout<<endl<<"Usage: "<< argv[0]<<"  <filename>"<< endl << endl;
    cout << "Example:      " << argv[0] << " arq1.in" << endl << endl; exit(0);}
	
  ifstream ifile;
  ifile.open(argv[1]);  if (!ifile) return(false);  

  int n, m;
  ifile >> n; ifile >> m;
  vector<double> jobsize(n);
  vector<double> machinespeed(m);
  for(int i=0; i<n; i++) ifile >> jobsize[i];
  for(int i=0; i<m; i++) ifile >> machinespeed[i];
  ifile.close();

  cout << endl;
  cout << "Numero de tarefas: " << n << endl;
  cout << "Tamanho das tarefas" << endl;
  for(int i=0; i<n; i++)
    cout << "T_" << i << ": " << jobsize[i] << endl;
  cout << "Velocidade das maquinas" << endl;
  for(int i=0; i<m; i++)
    cout << "M_" << i << ": " << machinespeed[i] << endl;
  cout << endl << endl;
  
  try {
/*--------------------------------------------------------------------------------- */	
/*--------------------------- ALTERE DAQUI PARA ABAIXO ---------------------------- */
/*--------------------------------------------------------------------------------- */	

    // Voce deve atualizar esta variavel com valores 0 e 1 de tal forma que
    // tarefa_maquina[i][j] = 1 SE_E_SOMENTE_SE a tarefa i foi escalonada na maq. j
    vector<vector<int> > tarefa_maquina(n, vector<int>(m));

    // mais abaixo eh feito um escalonamento aleatorio.
    // Nao se esqueca de alterar a geracao do escalonamento aleatorio para o
    // escalonamento obtido pelo seu programa linear inteiro

    
    // cabecalho comum para os programas lineares (descomente)
     int seed=0;
     GRBEnv env = GRBEnv();
     GRBModel model = GRBModel(env);
     model.getEnv().set(GRB_IntParam_Seed, seed);
     model.set(GRB_StringAttr_ModelName, "Escalonamento de Tarefas"); // prob. name
     model.set(GRB_IntAttr_ModelSense, GRB_MINIMIZE); // is a minimization problem  

    // Lembretes e sintaxes de alguns comandos:
    // GRBVar = nome do tipo das variaveis do Gurobi
    //
     //vector<GRBVar> x[m];
     double TP[m][n];
     GRBVar max = model.addVar(0,10000,1,GRB_CONTINUOUS,"max");
    // Para inserir uma variavel:
    // <variavel_do_tipo_GRBVar> =
    //            model.addVar(<lower_bound>,
    //                         <upper_bound> , 
    //                         <valor_na_funcao_objetivo>,
    //                         <GRB_CONTINUOUS ou GRB_BINARY GRB_INTEGER>
    //                         <string_do_nome_da_variavel>);
    //
    // Este comando deve ser executado depois de inserir todas as variaveis e antes de
    // inserir as restricoes.
     model.update();
    //
    // Para declarar variavel que armazena expressoes
     // for(int i = 0; i<n; i++) { //para cada maquina
     //   GRBLinExpr expr;
     //   for(int j = 0; j<m;j++) { //para cada tarefa
     // 	 expr+=x[m*i+j];
     //   }
     //   model.addConstr(expr >= 0);
     // }
    //
    // Para inserir uma restricao linear:
    // model.addConstr( <restricao_linear> );
    //
    // Comando para escrever o modelo produzido em um arquivo texto (apenas para debugar)
     model.update(); //Tem que dar update de novo pra ver as restricoes
     model.write("model.lp"); system("cat model.lp");
    //
    // Depois que construiu seu programa linear / linear inteiro, execute este comando
    // para resolver o programa linear
     model.optimize();
    //
    // Verifica se obteve solucao otima
     if (model.get(GRB_IntAttr_Status) != GRB_OPTIMAL) {
       cout << "Erro, sistema impossivel" << endl;
       exit(1);
     }
    //
    // Para obter o valor da variavel do programa linear/linear inteiro
    // deve ser executado apos o model.optimize()
    // 	<variavel_do_tipo_GRBVar>.get(GRB_DoubleAttr_X)

    
    // Faz um escalonamento aleatorio.
    // Remova esta parte e coloque o escalonamento
    // gerado pelo seu programa linear inteiro.
    for (int i=0; i<n; i++) 
      for (int j=0; j<m; j++)
	tarefa_maquina[i][j] = 0; // deixa cada maq. sem atribuicao
    // for (int i=0; i<n; i++)
    //   for (int j=0; j<m; j++)
    // 	//if(x[j][i].get(GRB_DoubleAttr_X) >= 0.999) {
    // 	//  cout << j << "  " << i << endl;
    // 	  tarefa_maquina[i][j] = 1;
    // 	}
	  
/*--------------------------------------------------------------------------------- */	
/*--------------------------- ALTERE DAQUI PARA CIMA ------------------------------ */
/*--------------------------------------------------------------------------------- */	

    cout << "\n\n";
      double makespan=0;
      cout << "Escalonamento obtido das tarefas nas maquinas\n";
      cout << "Notacao para tarefas : T_id(tamanho_original)\n";
      cout << "Notacao para maquinas: M_id(velocidade)\n\n";
      
      for (int j=0; j<m; j++) {
	double tmaq=0.0;
	cout << "M_"<<j<<"("<< machinespeed[j] << ") : ";
	for(int i=0; i<n; i++) {
	  if (tarefa_maquina[i][j] == 1) {
	    cout << "T_" << i << "(" << jobsize[i] << ") ";
	    tmaq += jobsize[i] / machinespeed[j];
	  }
	}
	cout << endl << "Tempo gasto pela maquina M_" <<j << ": " << tmaq << endl<<endl;
	if (tmaq>makespan) makespan = tmaq;
      }
      cout << "\nTempo para completar todas as tarefas: " << makespan << "s\n\n";
      //  } else  cout << "No solution" << "\n";
  }
  // catch (GRBException e) {
  //   cout << "Error code = " << e.getErrorCode() << endl;
  //   cout << e.getMessage() << endl;
  // }
  catch (...) {
    cout << "Exception during optimization" << endl;
  }
  return 0;
}
예제 #9
0
int
main(int argc,
     char *argv[])
{
  GRBEnv* env = 0;
  GRBVar* nutrition = 0;
  GRBVar* buy = 0;
  try
  {

    // Nutrition guidelines, based on
    // USDA Dietary Guidelines for Americans, 2005
    // http://www.health.gov/DietaryGuidelines/dga2005/
    const int nCategories = 4;
    string Categories[]   = { "calories",    "protein",  "fat", "sodium" };
    double minNutrition[] = {       1800,           91,     0,        0 };
    double maxNutrition[] = {       2200, GRB_INFINITY,    65,     1779 };

    // Set of foods
    const int nFoods = 9;
    string Foods[] = { "hamburger", "chicken", "hot dog", "fries", "macaroni", "pizza", "salad", "milk", "ice cream" };
    double cost[]  = { 2.49,             2.89,      1.50,    1.89,       2.09,    1.99,    2.49,   0.89,       1.59 };

    // Nutrition values for the foods
    double nutritionValues[][nCategories] = {
                      { 410, 24, 26,  730 },   // hamburger
                      { 420, 32, 10, 1190 },   // chicken
                      { 560, 20, 32, 1800 },   // hot dog
                      { 380,  4, 19,  270 },   // fries
                      { 320, 12, 10,  930 },   // macaroni
                      { 320, 15, 12,  820 },   // pizza
                      { 320, 31, 12, 1230 },   // salad
                      { 100,  8, 2.5, 125 },   // milk
                      { 330,  8, 10,  180 }    // ice cream
                    };

    // Model
    env = new GRBEnv();
    GRBModel model = GRBModel(*env);
    model.set(GRB_StringAttr_ModelName, "diet");

    // Create decision variables for the nutrition information,
    // which we limit via bounds
    nutrition = model.addVars(minNutrition, maxNutrition, 0, 0, Categories, nCategories);

    // Create decision variables for the foods to buy
    buy = model.addVars(0, 0, cost, 0, Foods, nFoods);

    // The objective is to minimize the costs
    model.set(GRB_IntAttr_ModelSense, 1);

    // Update model to integrate new variables
    model.update();

    // Nutrition constraints
    for (int i = 0; i < nCategories; ++i)
    {
      GRBLinExpr ntot = 0;
      for (int j = 0; j < nFoods; ++j)
      {
        ntot += nutritionValues[j][i] * buy[j];
      }
      model.addConstr(ntot == nutrition[i], Categories[i]);
    }

    // Solve
    model.optimize();
    printSolution(model, nCategories, nFoods, buy, nutrition);

    // Add constraint
    cout << "\nAdding constraint: at most 6 servings of dairy" << endl;
    model.addConstr(buy[7] + buy[8] <= 6.0, "limit_dairy");

    // Solve
    model.optimize();
    printSolution(model, nCategories, nFoods, buy, nutrition);

  }
  catch (GRBException e)
  {
    cout << "Error code = " << e.getErrorCode() << endl;
    cout << e.getMessage() << endl;
  }
  catch (...)
  {
    cout << "Exception during optimization" << endl;
  }

  delete[] nutrition;
  delete[] buy;
  delete env;
  return 0;
}
예제 #10
0
파일: gg_afg.cpp 프로젝트: j0rdm4n/vpsolver
void solve(Instance inst, bool hsol = false){    
    clock_t t0 = CURTIME;
    
    ArcflowMKP graph(inst);    
    const vector<Item> &items = inst.items;   
    
    GRBEnv* env = new GRBEnv();
    GRBModel master = GRBModel(*env);    
    master.set(GRB_StringAttr_ModelName, "GG");
    master.getEnv().set(GRB_IntParam_OutputFlag, 0);
    master.getEnv().set(GRB_IntParam_Threads, 1);          
    master.getEnv().set(GRB_IntParam_Method, 0); 

    GRBConstr rows[inst.m];
    for(int i = 0; i < inst.m; i++){
        GRBLinExpr lin = 0;
        rows[i] = master.addConstr(lin >= items[i].demand);
    }
    master.update();
        
    vector<GRBVar> vars;
    for(int i = 0; i < inst.m; i++){        
        GRBColumn col = GRBColumn();        
        col.addTerm(1, rows[i]);
        vars.push_back(master.addVar(0, GRB_INFINITY, 1, GRB_CONTINUOUS, col));
    }    
    
    printf("m: %d\n", inst.m);
    vector<double> values(inst.m);
    for(int itr = inst.m; ; itr++){
        master.optimize();
        printf("%d: %.6f (%.2fs)\n", itr, master.get(GRB_DoubleAttr_ObjVal), TIMEDIF(t0));        
        for(int i = 0; i < inst.m; i++)
            values[i] = rows[i].get(GRB_DoubleAttr_Pi);            

        vector<int_pair> sol = graph.knapsack(values, 1+EPSILON);
        if(sol.empty()) break;
        
        GRBColumn col = GRBColumn();        
        ForEach(itr, sol) col.addTerm(itr->second, rows[itr->first]);
        
        vars.push_back(master.addVar(0, GRB_INFINITY, 1, GRB_CONTINUOUS, col));
        master.update();
    }
        
    printf("zlp: %.6f\n", master.get(GRB_DoubleAttr_ObjVal));
    printf("nvars: %d\n", master.get(GRB_IntAttr_NumVars));
    printf("time: %.2fs\n", TIMEDIF(t0));
    
    if(hsol){ // find an heuristic solution if hsol = true
        ForEach(itr, vars)
            itr->set(GRB_CharAttr_VType, GRB_INTEGER);
        
        master.getEnv().set(GRB_IntParam_OutputFlag, 1);
        master.getEnv().set(GRB_IntParam_Threads, 1);
        //master.getEnv().set(GRB_IntParam_Presolve, 1);       
        //master.getEnv().set(GRB_IntParam_Method, 2);
        master.getEnv().set(GRB_IntParam_MIPFocus, 1);
        master.getEnv().set(GRB_DoubleParam_Heuristics, 1);
        master.getEnv().set(GRB_DoubleParam_MIPGap, 0);
        master.getEnv().set(GRB_DoubleParam_MIPGapAbs, 1-1e-5);  
        
        master.optimize();
        printf("Total run time: %.2f seconds\n", TIMEDIF(t0));
    }
    
    free(env);
}
예제 #11
0
int
main(int argc,
     char *argv[])
{
  GRBEnv* env = 0;
  GRBConstr* c = 0;
  GRBVar* v = 0;
  GRBVar** x = 0;
  GRBVar* slacks = 0;
  GRBVar* totShifts = 0;
  GRBVar* diffShifts = 0;
  int xCt = 0;
  try
  {

    // Sample data
    const int nShifts = 14;
    const int nWorkers = 7;

    // Sets of days and workers
    string Shifts[] =
      { "Mon1", "Tue2", "Wed3", "Thu4", "Fri5", "Sat6",
        "Sun7", "Mon8", "Tue9", "Wed10", "Thu11", "Fri12", "Sat13",
        "Sun14" };
    string Workers[] =
      { "Amy", "Bob", "Cathy", "Dan", "Ed", "Fred", "Gu" };

    // Number of workers required for each shift
    double shiftRequirements[] =
      { 3, 2, 4, 4, 5, 6, 5, 2, 2, 3, 4, 6, 7, 5 };

    // Worker availability: 0 if the worker is unavailable for a shift
    double availability[][nShifts] =
      { { 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1 },
        { 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0 },
        { 0, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1 },
        { 0, 1, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1 },
        { 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1 },
        { 1, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1 },
        { 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 } };

    // Model
    env = new GRBEnv();
    GRBModel model = GRBModel(*env);
    model.set(GRB_StringAttr_ModelName, "assignment");

    // Assignment variables: x[w][s] == 1 if worker w is assigned
    // to shift s. This is no longer a pure assignment model, so we must
    // use binary variables.
    x = new GRBVar*[nWorkers];
    for (int w = 0; w < nWorkers; ++w)
    {
      x[w] = model.addVars(nShifts);
      xCt++;
      model.update();
      for (int s = 0; s < nShifts; ++s)
      {
        ostringstream vname;
        vname << Workers[w] << "." << Shifts[s];
        x[w][s].set(GRB_DoubleAttr_UB, availability[w][s]);
        x[w][s].set(GRB_CharAttr_VType, GRB_BINARY);
        x[w][s].set(GRB_StringAttr_VarName, vname.str());
      }
    }

    // Slack variables for each shift constraint so that the shifts can
    // be satisfied
    slacks = model.addVars(nShifts);
    model.update();
    for (int s = 0; s < nShifts; ++s)
    {
      ostringstream vname;
      vname << Shifts[s] << "Slack";
      slacks[s].set(GRB_StringAttr_VarName, vname.str());
    }

    // Variable to represent the total slack
    GRBVar totSlack = model.addVar(0, GRB_INFINITY, 0, GRB_CONTINUOUS,
                                   "totSlack");

    // Variables to count the total shifts worked by each worker
    totShifts = model.addVars(nWorkers);
    model.update();
    for (int w = 0; w < nWorkers; ++w)
    {
      ostringstream vname;
      vname << Workers[w] << "TotShifts";
      totShifts[w].set(GRB_StringAttr_VarName, vname.str());
    }

    // Update model to integrate new variables
    model.update();

    GRBLinExpr lhs;

    // Constraint: assign exactly shiftRequirements[s] workers
    // to each shift s
    for (int s = 0; s < nShifts; ++s)
    {
      lhs = 0;
      lhs += slacks[s];
      for (int w = 0; w < nWorkers; ++w)
      {
        lhs += x[w][s];
      }
      model.addConstr(lhs == shiftRequirements[s], Shifts[s]);
    }

    // Constraint: set totSlack equal to the total slack
    lhs = 0;
    for (int s = 0; s < nShifts; ++s)
    {
      lhs += slacks[s];
    }
    model.addConstr(lhs == totSlack, "totSlack");

    // Constraint: compute the total number of shifts for each worker
    for (int w = 0; w < nWorkers; ++w) {
      lhs = 0;
      for (int s = 0; s < nShifts; ++s) {
        lhs += x[w][s];
      }
      ostringstream vname;
      vname << "totShifts" << Workers[w];
      model.addConstr(lhs == totShifts[w], vname.str());
    }

    // Objective: minimize the total slack
    GRBLinExpr obj = 0;
    obj += totSlack;
    model.setObjective(obj);

    // Optimize
    int status = solveAndPrint(model, totSlack, nWorkers, Workers, totShifts);
    if (status != GRB_OPTIMAL)
    {
      return 1;
    }

    // Constrain the slack by setting its upper and lower bounds
    totSlack.set(GRB_DoubleAttr_UB, totSlack.get(GRB_DoubleAttr_X));
    totSlack.set(GRB_DoubleAttr_LB, totSlack.get(GRB_DoubleAttr_X));

    // Variable to count the average number of shifts worked
    GRBVar avgShifts =
      model.addVar(0, GRB_INFINITY, 0, GRB_CONTINUOUS, "avgShifts");

    // Variables to count the difference from average for each worker;
    // note that these variables can take negative values.
    diffShifts = model.addVars(nWorkers);
    model.update();
    for (int w = 0; w < nWorkers; ++w) {
      ostringstream vname;
      vname << Workers[w] << "Diff";
      diffShifts[w].set(GRB_StringAttr_VarName, vname.str());
      diffShifts[w].set(GRB_DoubleAttr_LB, -GRB_INFINITY);
    }

    // Update model to integrate new variables
    model.update();

    // Constraint: compute the average number of shifts worked
    lhs = 0;
    for (int w = 0; w < nWorkers; ++w) {
      lhs += totShifts[w];
    }
    model.addConstr(lhs == nWorkers * avgShifts, "avgShifts");

    // Constraint: compute the difference from the average number of shifts
    for (int w = 0; w < nWorkers; ++w) {
      lhs = 0;
      lhs += totShifts[w];
      lhs -= avgShifts;
      ostringstream vname;
      vname << Workers[w] << "Diff";
      model.addConstr(lhs == diffShifts[w], vname.str());
    }

    // Objective: minimize the sum of the square of the difference from the
    // average number of shifts worked
    GRBQuadExpr qobj;
    for (int w = 0; w < nWorkers; ++w) {
      qobj += diffShifts[w] * diffShifts[w];
    }
    model.setObjective(qobj);

    // Optimize
    status = solveAndPrint(model, totSlack, nWorkers, Workers, totShifts);
    if (status != GRB_OPTIMAL)
    {
      return 1;
    }

  }
  catch (GRBException e)
  {
    cout << "Error code = " << e.getErrorCode() << endl;
    cout << e.getMessage() << endl;
  }
  catch (...)
  {
    cout << "Exception during optimization" << endl;
  }

  delete[] c;
  delete[] v;
  for (int i = 0; i < xCt; ++i) {
    delete[] x[i];
  }
  delete[] x;
  delete[] slacks;
  delete[] totShifts;
  delete[] diffShifts;
  delete env;
  return 0;
}
예제 #12
0
int
main(int argc,
     char *argv[])
{
  GRBEnv* env = 0;
  GRBVar* open = 0;
  GRBVar** transport = 0;
  int transportCt = 0;
  try
  {

    // Number of plants and warehouses
    const int nPlants = 5;
    const int nWarehouses = 4;

    // Warehouse demand in thousands of units
    double Demand[] = { 15, 18, 14, 20 };

    // Plant capacity in thousands of units
    double Capacity[] = { 20, 22, 17, 19, 18 };

    // Fixed costs for each plant
    double FixedCosts[] = { 12000, 15000, 17000, 13000, 16000 };

    // Transportation costs per thousand units
    double TransCosts[][nPlants] = {
                                     { 4000, 2000, 3000, 2500, 4500 },
                                     { 2500, 2600, 3400, 3000, 4000 },
                                     { 1200, 1800, 2600, 4100, 3000 },
                                     { 2200, 2600, 3100, 3700, 3200 }
                                   };

    // Model
    env = new GRBEnv();
    GRBModel model = GRBModel(*env);
    model.set(GRB_StringAttr_ModelName, "facility");

    // Plant open decision variables: open[p] == 1 if plant p is open.
    open = model.addVars(nPlants, GRB_BINARY);
    model.update();
    int p;
    for (p = 0; p < nPlants; ++p)
    {
      ostringstream vname;
      vname << "Open" << p;
      open[p].set(GRB_DoubleAttr_Obj, FixedCosts[p]);
      open[p].set(GRB_StringAttr_VarName, vname.str());
    }

    // Transportation decision variables: how much to transport from a plant p to a warehouse w
    transport = new GRBVar* [nWarehouses];
    int w;
    for (w = 0; w < nWarehouses; ++w)
    {
      transport[w] = model.addVars(nPlants);
      transportCt++;
      model.update();
      for (p = 0; p < nPlants; ++p)
      {
        ostringstream vname;
        vname << "Trans" << p << "." << w;
        transport[w][p].set(GRB_DoubleAttr_Obj, TransCosts[w][p]);
        transport[w][p].set(GRB_StringAttr_VarName, vname.str());
      }
    }

    // The objective is to minimize the total fixed and variable costs
    model.set(GRB_IntAttr_ModelSense, 1);

    // Update model to integrate new variables
    model.update();

    // Production constraints
    // Note that the right-hand limit sets the production to zero if
    // the plant is closed
    for (p = 0; p < nPlants; ++p)
    {
      GRBLinExpr ptot = 0;
      for (w = 0; w < nWarehouses; ++w)
      {
        ptot += transport[w][p];
      }
      ostringstream cname;
      cname << "Capacity" << p;
      model.addConstr(ptot <= Capacity[p] * open[p], cname.str());
    }

    // Demand constraints
    for (w = 0; w < nWarehouses; ++w)
    {
      GRBLinExpr dtot = 0;
      for (p = 0; p < nPlants; ++p)
      {
        dtot += transport[w][p];
      }
      ostringstream cname;
      cname << "Demand" << w;
      model.addConstr(dtot == Demand[w], cname.str());
    }

    // Guess at the starting point: close the plant with the highest
    // fixed costs; open all others

    // First, open all plants
    for (p = 0; p < nPlants; ++p)
    {
      open[p].set(GRB_DoubleAttr_Start, 1.0);
    }

    // Now close the plant with the highest fixed cost
    cout << "Initial guess:" << endl;
    double maxFixed = -GRB_INFINITY;
    for (p = 0; p < nPlants; ++p)
    {
      if (FixedCosts[p] > maxFixed)
      {
        maxFixed = FixedCosts[p];
      }
    }
    for (p = 0; p < nPlants; ++p)
    {
      if (FixedCosts[p] == maxFixed)
      {
        open[p].set(GRB_DoubleAttr_Start, 0.0);
        cout << "Closing plant " << p << endl << endl;
        break;
      }
    }

    // Use barrier to solve root relaxation
    model.getEnv().set(GRB_IntParam_Method, GRB_METHOD_BARRIER);

    // Solve
    model.optimize();

    // Print solution
    cout << "\nTOTAL COSTS: " << model.get(GRB_DoubleAttr_ObjVal) << endl;
    cout << "SOLUTION:" << endl;
    for (p = 0; p < nPlants; ++p)
    {
      if (open[p].get(GRB_DoubleAttr_X) == 1.0)
      {
        cout << "Plant " << p << " open:" << endl;
        for (w = 0; w < nWarehouses; ++w)
        {
          if (transport[w][p].get(GRB_DoubleAttr_X) > 0.0001)
          {
            cout << "  Transport " << transport[w][p].get(GRB_DoubleAttr_X) << " units to warehouse " << w << endl;
          }
        }
      }
      else
      {
        cout << "Plant " << p << " closed!" << endl;
      }
    }

  }
  catch (GRBException e)
  {
    cout << "Error code = " << e.getErrorCode() << endl;
    cout << e.getMessage() << endl;
  }
  catch (...)
  {
    cout << "Exception during optimization" << endl;
  }

  delete[] open;
  for (int i = 0; i < transportCt; ++i) {
    delete[] transport[i];
  }
  delete[] transport;
  delete env;
  return 0;
}
int main(int argc, char *argv[]) {

	// do we want to force integer solution?
	// if false, we solve a linear program without the integrity constraint
	bool integer_solution = false;
	// if objective_min_N is true then we solve the problem which minimizes total
	// number of vehicles in the simulation.
	// Otherwise, we minimize number of rebalancing trips
	bool objective_min_N = true;

	GRBEnv* env = 0; //< gurobi env
	GRBVar** rij = 0; // number of empty vehicles traveling between stations
	GRBVar** vi = 0; // number of vehicles available at station i

	// stations coordinates
	std::vector<std::vector<double> > stations;
	// distances or cost of traveling between the stations
	// internal vector stores "to where" and external vector stores "from where"
	std::vector<std::vector<double> > cost;
	// origin counts, size of n_rebalancing_periods x n_stations
	std::vector<std::vector<double> > origin_counts;
	// destination counts, size of n_rebalancing_periods x n_stations
	std::vector<std::vector<double> > dest_counts;
	// counts of vehicles in transit to each station, size of n_rebalancing_periods x n_stations
	std::vector<std::vector<double> > in_transit_counts;
	// cost of one idle vehicle in the system, when objective minimizes # vehicles, then set cost to 1,
	// when objective minimizes number of rebalancing vehicles then set cost to a huge number
	// (to make sure that this is always more expensive that rebalancing as it adds more vehicles to the system)
	double cost_of_veh = 1.0;
	double rebalancing_cost = 1.0;
	// what constraints do you want to take into account

	// input and output files declaration
	// simple_model
	//	bool simple_model = true;
	//	const string stationsFile = "/home/kasia/Dropbox/matlab/2015-09_FleetSizeEstimation/sampleFiles/stationsXY.txt";
	//	const string costMatrixFile = "/home/kasia/Dropbox/matlab/2015-09_FleetSizeEstimation/sampleFiles/costM3x3TT.txt";
	//	const string originCountsFile = "/home/kasia/Dropbox/matlab/2015-09_FleetSizeEstimation/sampleFiles/origCounts3x3TT.txt";
	//	const string destinationCountsFile = "/home/kasia/Dropbox/matlab/2015-09_FleetSizeEstimation/sampleFiles/destCounts3x3TT.txt";
	//	const string inTransitCountsFile = "/home/kasia/Dropbox/matlab/2015-09_FleetSizeEstimation/sampleFiles/inTransit3x3TT.txt";
	//	const string modelOutput = "rebalancing_formulation_simple.lp";
	//	const string solutionOutput = "rebalancing_solution_simple.sol";

	//	// simmobility files
	//		// ubuntu
	bool simple_model = false;
	const string stationsFile = "/home/kasia/Dropbox/matlab/2016-03-Demand_generation/facility_location/stations_ecbd34.txt";
	const string costMatrixFile = "/home/kasia/Dropbox/matlab/2015-09_FleetSizeEstimation/RebTimeInSecs34Stations.txt";
	const string originCountsFile = "/home/kasia/Dropbox/matlab/2015-09_FleetSizeEstimation/origCounts_rebEvery900_stations34.txt";
	const string destinationCountsFile = "/home/kasia/Dropbox/matlab/2015-09_FleetSizeEstimation/destCounts_rebEvery900_stations34.txt";
	const string inTransitCountsFile = "/home/kasia/Dropbox/matlab/2015-09_FleetSizeEstimation/inTransitReb900Stations34";
	const string modelOutput = "formulation_rebalancing.lp";
	const string solutionOutput = "rebalancing_solution.sol";

	// mac
	//		stationsFile = "/Users/katarzyna/Dropbox/matlab/2016-03-Demand_generation/facility_location/stations_ecbd34.txt";
	//		costMatrixFile = "/Users/katarzyna/Dropbox/matlab/2015-09_FleetSizeEstimation/RebTime34Stations.txt";
	//		originCountsFile = "/Users/katarzyna/Dropbox/matlab/2015-09_FleetSizeEstimation/origCounts_rebEvery900_stations34.txt";
	//		destinationCountsFile = "/Users/katarzyna/Dropbox/matlab/2015-09_FleetSizeEstimation/destCounts_rebEvery900_stations34.txt";


	//readFiles(stationsFile, stations);
	readFiles(costMatrixFile, cost);
	readFiles(originCountsFile, origin_counts);
	readFiles(destinationCountsFile, dest_counts);
	readFiles(inTransitCountsFile, in_transit_counts);

	//round cost of traveling between stations to be a multiple of the rebalancing period
	int reb_period = 1;
	if(!simple_model) {
		reb_period = 900; // in minutes, output from costOfRebalancing.m is in secs
	}

	int rounded_cost[cost.size()][cost.size()];
	for (unsigned int i = 0; i < cost.size(); i++){
		for (unsigned int j = 0; j < cost[0].size(); j++){
			if (i != j) {
				// cost in seconds from the beginning of the simulation
				rounded_cost[i][j] = roundUp((int)cost[i][j], reb_period);
				//std::cout << "roundUp((int)cost[" << i <<"][" << j << "] = " << rounded_cost[i][j] << std::endl;
			} else {
				rounded_cost[i][j] = 99999999; // 0
			}
		}
	}

	try {
		// number of stations in the network
		const int nStations = cost.size();
		const int nStSquare = pow (nStations, 2);
		//number of rebalancing periods = number of rows in the origin and destination counts, size of the first vector
		const int nRebPeriods = origin_counts.size();

		/***********************************************************************************
		 * Station matrix
		 ***********************************************************************************/
		// station matrix to access the elements of cost/rebalancing vectors
		// matrix form stores the indices of the cost vector i.e., for 3 stations [[0,1,2],[3,4,5],[6,7,8]]
		int stationMatrix [nStations][nStations];
		int indxCounter = 0;
		for(int i = 0; i < nStations; ++i) {
			for (int k = 0; k < nStations; ++k) {
				stationMatrix[i][k] = indxCounter;
				//std::cout << "stationMatrix["<< i<< "][" << k << "] = " << indxCounter << endl;
				indxCounter++;
			}
		}

		/***********************************************************************************
		 * Model
		 ***********************************************************************************/
		env = new GRBEnv();
		GRBModel model = GRBModel(*env);
		model.set(GRB_StringAttr_ModelName, "rebalancing");

		/***********************************************************************************
		 * Decision variables
		 ***********************************************************************************/
		int station;
		int time_;
		div_t divresult;
		// Number of vehicles available (idle) at each period of time and each station
		vi = new GRBVar* [nRebPeriods];
		// Number of empty vehicles traveling between stations
		rij = new GRBVar* [nRebPeriods];
		for ( time_ = 0; time_ < nRebPeriods; ++time_) {
			if (integer_solution) {
				vi[time_] = model.addVars(nStations, GRB_INTEGER);
				rij[time_] = model.addVars(nStSquare, GRB_INTEGER);
			} else {
				vi[time_] = model.addVars(nStations);
				rij[time_] = model.addVars(nStSquare);
			}
			model.update();
		}

		// Objective: minimize number of rebalancing trips
		if (!objective_min_N) {
			for ( time_ = 0; time_ < nRebPeriods; ++time_) {

				for (station = 0; station < nStations; ++station) {
					ostringstream cname;
					cname << "v_ti," << time_ << "," << station << ",0";

					// not minimized in the objective
					vi[time_][station].set(GRB_DoubleAttr_Obj, 0.0);
					vi[time_][station].set(GRB_StringAttr_VarName, cname.str());

				}
			}
			model.update();

			for ( time_ = 0; time_ < nRebPeriods; ++time_) {

				for(int depSt = 0; depSt < nStations; ++depSt){
					// std::cout << "departure station: " << depSt << std::endl;
					for (int arrSt = 0; arrSt < nStations; ++arrSt) {

						int idx = stationMatrix[depSt][arrSt];
						ostringstream vname;
						vname << "r_tij," << time_ << "," << depSt << ","<< arrSt;
						//std::cout << "nEmptyVhsTime." << time_ << "." << depSt << "."<< arrSt << "."<< idx << std::endl;

						if (depSt == arrSt) {
							// origin == destination
							// this variable should not exist because we do not send vehicles within the same station
							rij[time_][idx].set(GRB_DoubleAttr_Obj, 0.0);
							rij[time_][idx].set(GRB_StringAttr_VarName, vname.str());
							continue;
						}
						// std::cout << "nEmptyVhsTime." << time_ << ".indx." << station << ".from."<< divresult.quot << ".to." << divresult.rem << std:: endl;

						rij[time_][idx].set(GRB_DoubleAttr_Obj, rebalancing_cost * rounded_cost[depSt][arrSt]); // rebalancing_cost
						rij[time_][idx].set(GRB_StringAttr_VarName, vname.str());
					}
				}
			}
		} else { // Objective: minimize the total number of vehicles at time_ == 0
			// integer constraint relaxed
			ostringstream cname;
			ostringstream vname;
			for ( time_ = 0; time_ < nRebPeriods; ++time_) {

				for(int depSt = 0; depSt < nStations; ++depSt){
					cname.str("");
					cname.clear();
					cname << "v_ti," << time_ <<"," << depSt << ",0";
					if (time_ != 0) {
						cost_of_veh = 0.0;
					} else {
						cost_of_veh = 1.0;
					}
					vi[time_][depSt].set(GRB_DoubleAttr_Obj, cost_of_veh);
					vi[time_][depSt].set(GRB_StringAttr_VarName, cname.str());

					model.update();

					for (int arrSt = 0; arrSt < nStations; ++arrSt) {
						vname.str("");
						vname.clear();
						vname << "r_tij," << time_ << "," << depSt << ","<< arrSt;
						// std::cout << "Adding variable: r_tij," << time_ << "," << depSt << ","<< arrSt << " =  \n" << std::flush;
						int idx = stationMatrix[depSt][arrSt];

						if (depSt == arrSt) {
							rij[time_][idx].set(GRB_DoubleAttr_Obj, 0.0);
							rij[time_][idx].set(GRB_StringAttr_VarName, vname.str());
							// std::cout << "vname = " << vname.str() << "\n" << std::flush;
							// std::cout << "vname after clear= " << vname.str() << "\n" << std::flush;
							// std::cout << "Added variable: r_tij," << time_ << "," << depSt << ","<< arrSt << " = 0.0\n" << std::flush;
							continue;
						}

						if (time_ != 0) {
							rebalancing_cost = 0.0;
						} else {
							rebalancing_cost = 1.0;
						}

						int travel_time = (int) (rounded_cost[arrSt][depSt]/reb_period);
						// divresult.rem is start time of the arriving trips
						divresult = div (nRebPeriods + time_ - travel_time, nRebPeriods);

						// to prevent overwriting if there is sth already assigned to this variable
						if (rij[divresult.rem][idx].get(GRB_DoubleAttr_Obj) > 0) {

							if (travel_time > 1) {
								for (int k = 1; k < travel_time; ++k) {
									divresult = div (nRebPeriods + time_ - travel_time + k, nRebPeriods);
									// to prevent overwriting if there is sth already assigned to this variable
									if (rij[divresult.rem][idx].get(GRB_DoubleAttr_Obj) > 0) {
										continue;
									}
									rij[divresult.rem][idx].set(GRB_DoubleAttr_Obj, rebalancing_cost);
									vname.str("");
									vname.clear();
									vname << "r_tij," << divresult.rem << "," << depSt << ","<< arrSt;
									rij[divresult.rem][idx].set(GRB_StringAttr_VarName, vname.str());
									//std::cout << "Added variable: r_tij," << divresult.rem << "," << depSt << ","<< arrSt << " = " << rebalancing_cost << "\n" << std::flush;
								}
							}
							continue;
						}

						rij[divresult.rem][idx].set(GRB_DoubleAttr_Obj, rebalancing_cost);
						vname.str("");
						vname.clear();
						vname << "r_tij," << divresult.rem << "," << depSt << ","<< arrSt;
						rij[divresult.rem][idx].set(GRB_StringAttr_VarName, vname.str());
						//std::cout << "Added variable: r_tij," << divresult.rem << "," << depSt << ","<< arrSt << " = " << rebalancing_cost << "\n" << std::flush;

						if (travel_time > 1) {
							for (int k = 1; k < travel_time; ++k) {
								divresult = div (nRebPeriods + time_ - travel_time + k, nRebPeriods);
								// to prevent overwriting if there is sth already assigned to this variable
								if (rij[divresult.rem][idx].get(GRB_DoubleAttr_Obj) > 0) {
									continue;
								}
								rij[divresult.rem][idx].set(GRB_DoubleAttr_Obj, rebalancing_cost);
								vname.str("");
								vname.clear();
								vname << "r_tij," << divresult.rem << "," << depSt << ","<< arrSt;
								rij[divresult.rem][idx].set(GRB_StringAttr_VarName, vname.str());
								//std::cout << "Added variable: r_tij," << divresult.rem << "," << depSt << ","<< arrSt << " = " << rebalancing_cost << "\n" << std::flush;
							}
						}
					}
				}
			}
		}
		model.update();

		/***********************************************************************************
		 * Objective function
		 ***********************************************************************************/
		// The objective is to minimize the number of vehicles traveling in the network (and cost associated with it)
		// Optimization sense:  The default +1.0 value indicates that the objective is to minimize the
		// objective. Setting this attribute to -1 changes the sense to maximization
		model.set(GRB_IntAttr_ModelSense, 1);
		model.update();

		/***********************************************************************************
		 * Constraint 1: The number of vehicles must be sufficient to serve the demand
		 ***********************************************************************************/
		// This constraint is set to ensure that the number of vehicles available at each station i
		// is sufficient to serve the demand within this station.
		// If there is not enough vehicles, then we do rebalancing to make sure we can serve the trips
		for ( time_ = 0; time_ < nRebPeriods; ++time_) {
			// Current demand
			int booking_requests[nStations];
			for (int i = 0; i < nStations; ++i) {
				// booking_requests = departing_vehicles - arriving_vehicles (how many more vehicles do we need)
				booking_requests[i] = origin_counts[time_][i] - dest_counts[time_][i];
				// std::cout << origin_counts[time_][i] << " - " << dest_counts[time_][i] << " = " << dem_curr[i] << std::endl;
			}

			GRBLinExpr reb_dep = 0;
			GRBLinExpr reb_arr = 0;

			for(int depSt = 0; depSt < nStations; ++depSt){
				// std::cout << "departure station: " << depSt << std::endl;
				for (int arrSt = 0; arrSt < nStations; ++arrSt) {

					if (depSt != arrSt) {
						int idx = stationMatrix[depSt][arrSt];
						int idx2 = stationMatrix[arrSt][depSt];
						reb_dep += rij[time_][idx];
						// std::cout << "rounded_cost = " << (int)rounded_cost[depSt][arrSt]/reb_period -1 << std::endl;
						// cost is expressed in the number of reb periods, i.e., 1,2,3,...nRebPeriods
						int travel_cost = (int) (rounded_cost[depSt][arrSt]/reb_period); // maybe ceil would be better than just int
						// ceil version of the above line
						// int travel_cost = (int) ceil((rounded_cost[depSt][arrSt]/reb_period));
						if (travel_cost > time_) {
							int dep_time = nRebPeriods + time_ - travel_cost;
							reb_arr += rij[dep_time][idx2];
						} else {
							int dep_time = time_ - travel_cost;
							reb_arr += rij[dep_time][idx2];
						}
					}
				}
				ostringstream cname;
				cname << "demand_ti" << time_ << "." << depSt;
				model.addConstr(vi[time_][depSt] + reb_arr - reb_dep >= booking_requests[depSt], cname.str());

				//std::cout << "Constraint 1 demand: " << time_  << "." << depSt << std::endl;
				reb_arr.clear();
				reb_dep.clear();
			}
		}
		model.update();
		std::cout << "Constraint set 1 added." << std::endl;

		/***********************************************************************************
		 * Constraint 2: Constant number of vehicles over time
		 ***********************************************************************************/
		// This constraint is set to ensure that the total number of vehicles in the system does not change
		// over time
		// the total number of vehicles in the system is equal to the sum of the vehicles owned by each station
		// vehicles owned by station i: available_veh + cust_arriving + cust_in_transit_to_station + empty_arr + empty_in_transit

		int cust_balance_at[nStations];
		int cust_vhs_at_t[time_];
		for ( time_ = 0; time_ < nRebPeriods; ++time_) {
			cust_vhs_at_t[time_] = 0;
			for (int i = 0; i < nStations; ++i) {
				// vhs_owned is the number of vehicles owned by station i
				// this number does not account for rebalancing vehicles
				// vhs_owned = arriving_costomers + in_transit_to_station
				cust_balance_at[i] = dest_counts[time_][i] + in_transit_counts[time_][i];
				// std::cout << "vhs_owned[" << i << "] = " << vhs_owned[i] << std::endl;
				cust_vhs_at_t[time_] += cust_balance_at[i];
			}
			if (time_ == 0) { // one print function to validate the above loop
				std::cout << "cust_vhs_at_t[" << time_ << "] = " << cust_vhs_at_t[time_] << std::endl;
			}
		}

		GRBLinExpr idle_veh = 0; // Gurobi Linear Expression, total number of idle vehicles now
		GRBLinExpr reb_arr = 0; // Gurobi Linear Expression, total number of rebalancing vehicles arriving and in transit to station i

		GRBLinExpr idle_veh_prev = 0; // Gurobi Linear Expression, total number of idle vehicles at previous interval
		GRBLinExpr reb_arr_prev = 0; // Gurobi Linear Expression, total number of rebalancing vehicles arriving and in transit to station i at previous time

		for ( time_ = 0; time_ < nRebPeriods; ++time_) {
			std::cout << "time_ = " << time_ << std::endl;

			// adding variables at current time t
			for(int i = 0; i < nStations; ++i) {
				// idle vehicles at station i at time t
				idle_veh += vi[time_][i];

				for(int j = 0; j < nStations; ++j) {
					if (i != j) {

						// travel_time is expressed in the number of reb periods, i.e., 1,2,3,...nRebPeriods
						// travel_time for trips arriving to i from j
						int travel_time = (int) (rounded_cost[j][i]/reb_period);
						// index of vehicles arriving at i from j (departed from j to i travel_time ago)
						int idx_arr = stationMatrix[j][i];
						// divresult.rem is start time of the arriving trips
						divresult = div (nRebPeriods + time_ - travel_time, nRebPeriods);
						// std::cout << "Current time = " << time_ << ", travel_time = " << travel_time << ", divresult.rem = " << divresult.rem << ", idx_arr = "<< idx_arr << std::endl;
						reb_arr += rij[divresult.rem][idx_arr];
						// empty trips in transit (not arriving yet)
						// if tt > 1 -> all trips started after divresult.rem and before time_
						if (travel_time > 1) {
							for (int k = 1; k < travel_time; ++k) {
								divresult = div (nRebPeriods + time_ - travel_time + k, nRebPeriods);
								// std::cout << "if travel_time > 1 => " << time_ << ", travel_time = " << travel_time << ", divresult.rem = " << divresult.rem << ", idx_arr = "<< idx_arr << std::endl;
								reb_arr += rij[divresult.rem][idx_arr];
							}
						}
					}
				}
			}

			// adding variables at time (t-1)
			for(int i = 0; i < nStations; ++i) {
				// idle vehicles at station i at time (t - 1)
				divresult = div (nRebPeriods + time_ - 1, nRebPeriods);
				idle_veh_prev += vi[divresult.rem][i];

				for(int j = 0; j < nStations; ++j) {
					if (i != j) {

						// travel_time is expressed in the number of reb periods, i.e., 1,2,3,...nRebPeriods
						// travel_time for trips arriving to i from j
						int travel_time = (int) (rounded_cost[j][i]/reb_period);
						// index of vehicles arriving at i from j (departed from j to i travel_time ago)
						int idx_arr = stationMatrix[j][i];
						// divresult.rem is start time of the arriving trips
						divresult = div (nRebPeriods + time_ - 1 - travel_time, nRebPeriods);
						// std::cout << "Previous time = " << nRebPeriods + time_ - 1 << ", travel_time = " << travel_time << ", divresult.rem = " << divresult.rem << ", idx_arr = "<< idx_arr << std::endl;
						reb_arr_prev += rij[divresult.rem][idx_arr];
						// empty trips in transit (not arriving yet)
						// if tt > 1 -> all trips started after divresult.rem and before time_
						if (travel_time > 1) {
							for (int k = 1; k < travel_time; ++k) {
								divresult = div (nRebPeriods + time_ - 1 - travel_time + k, nRebPeriods);
								reb_arr_prev += rij[divresult.rem][idx_arr];
							}
						}
					}
				}
			}

			// add constraints
			ostringstream cname;
			cname << "supply_t" << time_ ;

			// total number of vehicles at time t == total number of vehicles at time (t-1)
			divresult = div (nRebPeriods + time_ - 1, nRebPeriods);
			model.addConstr(idle_veh + reb_arr + cust_vhs_at_t[time_] == idle_veh_prev + reb_arr_prev + cust_vhs_at_t[divresult.rem], cname.str());
			model.update();

			idle_veh.clear();
			idle_veh_prev.clear();
			reb_arr.clear();
			reb_arr_prev.clear();

		} // end constraints loop: for ( time_ = 0; time_ < nRebPeriods; ++time_)
		std::cout << "Constraint set 2 added." << std::endl;

		/***********************************************************************************
		 * Constraint 3: Flow conservation at station i
		 ***********************************************************************************/
		// This constraint is set to ensure that the number of vehicles available at station i at time t
		// is equal to the number of vehicles available at this station in previous time interval
		// plus whatever has arrived minus whatever has departed
		for ( time_ = 0; time_ < nRebPeriods; ++time_) {
			// Current demand
			int dem_curr[nStations];
			for (int i = 0; i < nStations; ++i) {
				// current demand = arriving_vehicles - departing_vehicles
				dem_curr[i] = dest_counts[time_][i] - origin_counts[time_][i];
				// std::cout << origin_counts[time_][i] << " - " << dest_counts[time_][i] << " = " << dem_curr[i] << std::endl;
			}

			GRBLinExpr reb_dep = 0;
			GRBLinExpr reb_arr = 0;

			for(int depSt = 0; depSt < nStations; ++depSt){
				// std::cout << "departure station: " << depSt << std::endl;
				for (int arrSt = 0; arrSt < nStations; ++arrSt) {

					if (depSt != arrSt) {
						int idx = stationMatrix[depSt][arrSt];
						int idx2 = stationMatrix[arrSt][depSt];
						reb_dep += rij[time_][idx];
						// std::cout << "rounded_cost = " << (int)rounded_cost[depSt][arrSt]/reb_period -1 << std::endl;
						int travel_cost = (int) (rounded_cost[depSt][arrSt]/reb_period);
						if (travel_cost > time_) {
							int dep_time = nRebPeriods + time_ - travel_cost;
							reb_arr += rij[dep_time][idx2];
						} else {
							int dep_time = time_ - travel_cost;
							reb_arr += rij[dep_time][idx2];
						}
					}
				}
				ostringstream cname;
				cname << "flow_ti" << time_ << "." << depSt;
				if (time_ != nRebPeriods - 1) {
					model.addConstr(vi[time_ + 1][depSt] ==
							vi[time_][depSt] + reb_arr - reb_dep + dem_curr[depSt], cname.str());
				} else {
					// if we are in the last interval then we compare against the first interval of the next day
					// here: vi(t=0) == vi(t=Tp)
					model.addConstr(vi[0][depSt] ==
							vi[time_][depSt] + reb_arr - reb_dep + dem_curr[depSt], cname.str());
				}
				//std::cout << "Constraint 1 vi @: " << time_  << "." << depSt << std::endl;
				reb_arr.clear();
				reb_dep.clear();
			}
		}
		model.update();
		std::cout << "Constraint set 3 added." << std::endl;
		/***********************************************************************************
		 * Solve the problem and print solution to the console and to the file
		 ***********************************************************************************/
		model.optimize();
		model.write(modelOutput);

		int total_demand = 0;
		int dem_curr[nStations];
		for (int i = 0; i < nStations; ++i) {
			dem_curr[i] = dest_counts[0][i] + in_transit_counts[0][i];
			total_demand += dem_curr[i];
		}

		double numOfVeh = model.get(GRB_DoubleAttr_ObjVal) + total_demand; //plus rebalancing counts

		cout << "\nTOTAL NUMBER OF VEHICLES: " << numOfVeh << std::endl;
		cout << "\nTOTAL NUMBER OF AVAILABLE VEH AT TIME 0: " << model.get(GRB_DoubleAttr_ObjVal) << std::endl;
		//		cout << "SOLUTION:" << endl;
		//
		//		for (time_ = 0; time_ < nRebPeriods; ++time_){
		//
		//			for(int depSt = 0; depSt < nStations; ++depSt){
		//				for (int arrSt = 0; arrSt < nStations; ++arrSt) {
		//					if(depSt != arrSt) {
		//						int idx = stationMatrix[depSt][arrSt];
		//						cout << "At time " << time_ << ", rebalancing from station " << depSt <<
		//								" to station " << arrSt << " send "  <<
		//								empty_veh[time_][idx].get(GRB_DoubleAttr_X) << " vehicles." << std::endl;
		//					}
		//				}
		//			}
		//		}
		//
		//		for (time_ = 0; time_ < nRebPeriods; ++time_){
		//			for(int arrSt = 0; arrSt < nStations; ++arrSt){
		//				cout << "At time " << time_ << " at station " << arrSt <<
		//						" number of available vehicles: " << vhs_st_i[time_][arrSt].get(GRB_DoubleAttr_X) << std::endl;
		//			}
		//			cout << "At time " << time_ << " number of vehicles in transit: "
		//					<< in_transit[time_].get(GRB_DoubleAttr_X) << std::endl;
		//		}

		model.write(solutionOutput);

	} catch(GRBException e) {
		cout << "Error code = " << e.getErrorCode() << std::endl;
		cout << e.getMessage() << std::endl;
	} catch(...) {
		cout << "Exception during optimization" << std::endl;
	}
	return 0;
}
예제 #14
0
int main(int argc, char *argv[]) 
{
  Digraph g;  // graph declaration
  string digraph_matching_filename;
  DiNodeName vname(g);  // name of graph nodes
  Digraph::NodeMap<double> px(g),py(g);  // xy-coodinates for each node
  Digraph::NodeMap<int> vcolor(g);// color of nodes
  Digraph::ArcMap<int> ecolor(g); // color of edges
  ArcWeight lpvar(g);    // used to obtain the contents of the LP variables
  ArcWeight weight(g);   // edge weights
  srand48(1);


  // uncomment one of these lines to change default pdf reader, or insert new one
  //set_pdfreader("open");    // pdf reader for Mac OS X
  //set_pdfreader("xpdf");    // pdf reader for Linux
  //set_pdfreader("evince");  // pdf reader for Linux

      
  // double cutoff;   // used to prune non promissing branches (of the B&B tree)
  if (argc!=2) {
    cout<<endl<<"Usage: "<< argv[0]<<" <digraph_matching_filename>"<<endl<<endl;
    cout << "Example:      " << argv[0] << " digr_bipartite_100_10" << endl << endl;
    exit(0);}

  digraph_matching_filename = argv[1];
  ReadListDigraph(digraph_matching_filename,g,vname,weight,px,py,0);
  //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

  GRBEnv env = GRBEnv();
  GRBModel model = GRBModel(env);
  model.set(GRB_IntAttr_ModelSense, GRB_MAXIMIZE); // is a maximization problem

  /* LPI variables */
  Digraph::ArcMap<GRBVar> x(g); // variable for connections, 1=connected, 0=not connected
  
  GRBLinExpr expressao;
  for (Digraph::ArcIt e(g); e != INVALID; ++e) {
    x[e] = model.addVar(0.0, 1.0, weight[e], GRB_CONTINUOUS);
    // Exercise: Using bipartite graphs, explain why we can use continuous
    // variables and still obtain integer solutions
  }
  model.update();
  
  for (Digraph::NodeIt v(g); v!=INVALID; ++v) {
    GRBLinExpr exprin, exprout;
    int n_arcs_in=0,n_arcs_out=0;
    // for each node, the number of arcs leaving is at most 1
    // remember: the graph is bipartite, with arcs going from one part to the other
    for (Digraph::InArcIt e(g,v); e != INVALID; ++e) {exprin += x[e]; n_arcs_in++;}
    if (n_arcs_in > 0)  {model.addConstr(exprin  <= 1 ); vcolor[v] = BLUE;}
    
    // for each node, the number of arcs entering is at most 1 
    for (Digraph::OutArcIt e(g,v); e != INVALID; ++e) {exprout += x[e]; n_arcs_out++;}
    if (n_arcs_out > 0) {model.addConstr(exprout <= 1 ); vcolor[v] = RED;}
  }
  //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  try {
    model.optimize();
    double soma=0.0;
    int cor=0;
    for (Digraph::ArcIt e(g); e!=INVALID; ++e) {
      lpvar[e] = x[e].get(GRB_DoubleAttr_X);
      if (lpvar[e] > 1.0 - EPS) { soma += weight[e]; ecolor[e] = (cor % 8) + 2; cor++; }
      else ecolor[e] = NOCOLOR; }
    cout << "Maximum Bipartite Matching = " << soma << endl;

    // Esta rotina precisa do programa neato/dot do Graphviz 
    ViewListDigraph(g,vname,px,py,vcolor,ecolor,
    "maximum weighted matching in graph with "+IntToString(countNodes(g))+
    	    " nodes:"+DoubleToString(soma));
  } catch(GRBException e) {
    cerr << "Nao foi possivel resolver o PLI." << endl;
    cerr << "Codigo de erro = " << e.getErrorCode() << endl;
    cerr << e.getMessage();
  }
  return 0;
}
int main(int argc, char *argv[]) 
{
  int time_limit;
  char name[1000];
  double cutoff=0.0;
  ListGraph g;
  EdgeWeight lpvar(g);
  EdgeWeight weight(g);
  NodeName vname(g);
  ListGraph::NodeMap<double> posx(g),posy(g);
  string filename;

  int seed=1;


  // uncomment one of these lines to change default pdf reader, or insert new one
  //set_pdfreader("open");    // pdf reader for Mac OS X
  //set_pdfreader("xpdf");    // pdf reader for Linux
  //set_pdfreader("evince");  // pdf reader for Linux

  srand48(seed);
  time_limit = 3600; // solution must be obtained within time_limit seconds
  if (argc!=2) {cout<< endl << "Usage: "<< argv[0]<<" <graph_filename>"<<endl << endl <<
      "Example: " << argv[0] << " gr_berlin52" << endl <<
      "         " << argv[0] << " gr_att48" << endl << endl; exit(0);}
  
  else if (!FileExists(argv[1])) {cout<<"File "<<argv[1]<<" does not exist."<<endl; exit(0);}
  filename = argv[1];
  
  // Read the graph
  if (!ReadListGraph(filename,g,vname,weight,posx,posy)) 
    {cout<<"Error reading graph file "<<argv[1]<<"."<<endl;exit(0);}

  TSP_Data tsp(g,vname,posx,posy,weight); 
  ListGraph::EdgeMap<GRBVar> x(g);
  GRBEnv env = GRBEnv();
  GRBModel model = GRBModel(env);
#if GUROBI_NEWVERSION
  model.getEnv().set(GRB_IntParam_LazyConstraints, 1);
  model.getEnv().set(GRB_IntParam_Seed, seed);
#else
  model.getEnv().set(GRB_IntParam_DualReductions, 0); // Dual reductions must be disabled when using lazy constraints
#endif
  model.set(GRB_StringAttr_ModelName, "Undirected TSP with GUROBI"); // name to the problem
  model.set(GRB_IntAttr_ModelSense, GRB_MINIMIZE); // is a minimization problem
  
  // Add one binary variable for each edge and also sets its cost in the objective function
  for (ListGraph::EdgeIt e(g); e!=INVALID; ++e) {
    sprintf(name,"x_%s_%s",vname[g.u(e)].c_str(),vname[g.v(e)].c_str());
    x[e] = model.addVar(0.0, 1.0, weight[e],GRB_BINARY,name);
  }
  model.update(); // run update to use model inserted variables

  // Add degree constraint for each node (sum of solution edges incident to a node is 2)
  for (ListGraph::NodeIt v(g); v!=INVALID; ++v) {
    GRBLinExpr expr;
    for (ListGraph::IncEdgeIt e(g,v); e!=INVALID; ++e) expr += x[e];
    //aqui model.addConstr(expr == 2 ); what? ignorou!
    model.addConstr(expr == 2 );

  }

  try {
    model.update(); // Process any pending model modifications.
    if (time_limit >= 0) model.getEnv().set(GRB_DoubleParam_TimeLimit,time_limit);

    subtourelim cb = subtourelim(tsp , x);
    model.setCallback(&cb);
    
    tsp.max_perturb2opt_it = 200; //1000; // number of iterations used in heuristic TSP_Perturb2OPT
    TSP_Perturb2OPT(tsp);
    if (tsp.BestCircuitValue < DBL_MAX) cutoff = tsp.BestCircuitValue-BC_EPS; // 
    // optimum value for gr_a280=2579, gr_xqf131=566.422, gr_drilling198=15808.652
    if (cutoff > 0) model.getEnv().set(GRB_DoubleParam_Cutoff, cutoff );
    model.update(); // Process any pending model modifications.
    model.optimize();

    double soma=0.0;
    for (ListGraph::EdgeIt e(g); e!=INVALID; ++e) {
      lpvar[e] = x[e].get(GRB_DoubleAttr_X);
      if (lpvar[e] > 1-BC_EPS ) {
	soma += weight[e];
	if (
	    (vname[g.u(e)] == "243")||(vname[g.v(e)] == "243") ||
	    (vname[g.u(e)] == "242")||(vname[g.v(e)] == "242")
	    ) {
	  cout << "Achei, x("<< vname[g.u(e)] << " , " << vname[g.v(e)] << " = " << lpvar[e] <<"\n";
	}
      }
    }

    cout << "Solution cost = "<< soma << endl;
    Update_Circuit(tsp,x); // Update the circuit in x to tsp circuit variable (if better)
    ViewTspCircuit(tsp);

  }catch (...) {
    if (tsp.BestCircuitValue < DBL_MAX) {
      cout << "Heuristic obtained optimum solution"  << endl;
      ViewTspCircuit(tsp);
      return 0;
    }else {
      cout << "Graph is infeasible"  << endl;
      return 1;
    }
  }
}
int main(int argc, char *argv[]) 
{
  int nt;
  Digraph g;  // graph declaration
  string digraph_steiner_filename;
  DiNodeName vname(g);  // name of graph nodes
  Digraph::NodeMap<double> px(g),py(g);  // xy-coodinates for each node
  Digraph::NodeMap<int> vcolor(g);// color of nodes
  Digraph::ArcMap<int> ecolor(g); // color of edges
  ArcWeight lpvar(g);    // used to obtain the contents of the LP variables
  ArcWeight weight(g);   // edge weights
  Digraph::ArcMap<GRBVar> x(g); // binary variables for each arc
  vector <DiNode> V;
  int seed=0;
  srand48(1);

  // uncomment one of these lines to change default pdf reader, or insert new one
  //set_pdfreader("open");    // pdf reader for Mac OS X
  //set_pdfreader("xpdf");    // pdf reader for Linux
  //set_pdfreader("evince");  // pdf reader for Linux

    
  // double cutoff;   // used to prune non promissing branches (of the B&B tree)
  if (argc!=2) {cout<< endl << "Usage: "<< argv[0]<<"  <digraph_steiner_filename>"<< endl << endl;
    cout << "Examples:      " << argv[0] << " gr_berlin52.steiner" << endl;
    cout << "               " << argv[0] << " gr_usa48.steiner" << endl << endl;
    exit(0);}

  digraph_steiner_filename = argv[1];

  //int time_limit = 3600; // solution must be obtained within time_limit seconds
  GRBEnv env = GRBEnv();
  GRBModel model = GRBModel(env);
  model.getEnv().set(GRB_IntParam_LazyConstraints, 1);
  model.getEnv().set(GRB_IntParam_Seed, seed);
  model.set(GRB_StringAttr_ModelName, "Oriented Steiner Tree with GUROBI"); // prob. name
  model.set(GRB_IntAttr_ModelSense, GRB_MINIMIZE); // is a minimization problem

  ReadListDigraphSteiner(digraph_steiner_filename,g,vname,weight,px,py,1,nt,V); 
  Steiner_Instance T(g,vname,px,py,weight,nt,V);
  //for (DiNodeIt v(g);v!=INVALID;++v){ if(v==T.V[0])vcolor[v]=RED; else vcolor[v]=BLUE;}
  //for (int i=1;i<T.nt;i++) vcolor[T.V[i]] = MAGENTA;
  //for (ArcIt e(g); e != INVALID; ++e) ecolor[e] = BLUE;
  //ViewListDigraph(g,vname,px,py,vcolor,ecolor,"Triangulated graph");
  
  // Generate the binary variables and the objective function
  // Add one binary variable for each edge and set its cost in the objective function
  for (Digraph::ArcIt e(g); e != INVALID; ++e) {
    char name[100];
    sprintf(name,"X_%s_%s",vname[g.source(e)].c_str(),vname[g.target(e)].c_str());
    x[e] = model.addVar(0.0, 1.0, weight[e],GRB_BINARY,name); }
  model.update(); // run update to use model inserted variables
  try {
    //if (time_limit >= 0) model.getEnv().set(GRB_DoubleParam_TimeLimit,time_limit);
    //model.getEnv().set(GRB_DoubleParam_ImproveStartTime,10); //try better sol. aft. 10s
    // if (cutoff > 0) model.getEnv().set(GRB_DoubleParam_Cutoff, cutoff );

    ConnectivityCuts cb = ConnectivityCuts(T , x);
    model.setCallback(&cb);
    model.update();
    //model.write("model.lp"); system("cat model.lp");
    model.optimize();

    double soma=0.0;
    for (DiNodeIt v(g);v!=INVALID;++v) vcolor[v]=BLUE; // all nodes BLUE
    for (int i=0;i<T.nt;i++) vcolor[T.V[i]]=MAGENTA; // change terminals to MAGENTA
    vcolor[T.V[0]]=RED; // change root to RED
    for (Digraph::ArcIt e(g); e!=INVALID; ++e) {
      lpvar[e] = x[e].get(GRB_DoubleAttr_X);
      if (lpvar[e] > 1.0 - EPS) { soma += weight[e]; ecolor[e] = RED; }
      else ecolor[e] = NOCOLOR; }
    cout << "Steiner Tree Value = " << soma << endl;
    ViewListDigraph(g,vname,px,py,vcolor,ecolor,
	"Steiner Tree cost in graph with "+IntToString(T.nnodes)+
	" nodes and "+IntToString(T.nt)+" terminals: "+DoubleToString(soma));
  } catch (...) {cout << "Error during callback..." << endl; }
  return 0;
}
int main(int argc, char *argv[]) 
{
  int time_limit;
  char name[1000];
  ListGraph g;
  EdgeWeight lpvar(g);
  EdgeWeight weight(g);
  NodeName vname(g);
  ListGraph::NodeMap<double> posx(g),posy(g);
  string filename;
  int seed=1;


  // uncomment one of these lines to change default pdf reader, or insert new one
  //set_pdfreader("open");    // pdf reader for Mac OS X
  //set_pdfreader("xpdf");    // pdf reader for Linux
  //set_pdfreader("evince");  // pdf reader for Linux

  srand48(seed);
  time_limit = 3600; // solution must be obtained within time_limit seconds
  if (argc!=2) {cout<< endl << "Usage: "<< argv[0]<<" <graph_filename>"<<endl << endl <<
      "Example: " << argv[0] << " gr_berlin52" << endl <<
      "         " << argv[0] << " gr_att48" << endl << endl; exit(0);}
  
  else if (!FileExists(argv[1])) {cout<<"File "<<argv[1]<<" does not exist."<<endl; exit(0);}
  filename = argv[1];
  
  // Read the graph
  if (!ReadListGraph(filename,g,vname,weight,posx,posy)) 
    {cout<<"Error reading graph file "<<argv[1]<<"."<<endl;exit(0);}

  TSP_Data tsp(g,vname,posx,posy,weight); 
  ListGraph::EdgeMap<GRBVar> x(g);
  GRBEnv env = GRBEnv();
  GRBModel model = GRBModel(env);
#if GUROBI_NEWVERSION
  model.getEnv().set(GRB_IntParam_LazyConstraints, 1);
  model.getEnv().set(GRB_IntParam_Seed, seed);
#else
  model.getEnv().set(GRB_IntParam_DualReductions, 0); // Dual reductions must be disabled when using lazy constraints
#endif
  model.set(GRB_StringAttr_ModelName, "Emparelhamento perfeito with GUROBI");
  // name to the problem
  model.set(GRB_IntAttr_ModelSense, GRB_MAXIMIZE); // is a minimization problem
  
  // Add one binary variable for each edge and also sets its cost in
  //the objective function
  for (ListGraph::EdgeIt e(g); e!=INVALID; ++e) {
    sprintf(name,"x_%s_%s",vname[g.u(e)].c_str(),vname[g.v(e)].c_str());
    x[e] = model.addVar(0.0, 1.0, weight[e],GRB_BINARY,name);
  }
  model.update(); // run update to use model inserted variables

  // Add degree constraint for each node (sum of solution edges incident to a node is 2)
  for (ListGraph::NodeIt v(g); v!=INVALID; ++v) {
    GRBLinExpr expr;
    for (ListGraph::IncEdgeIt e(g,v); e!=INVALID; ++e) expr += x[e];
    //aqui model.addConstr(expr == 2 ); what? ignorou!
    model.addConstr(expr == 1);
  }

  try {
    model.update(); // Process any pending model modifications.
    if (time_limit >= 0) model.getEnv().set(GRB_DoubleParam_TimeLimit,time_limit);

    model.update(); // Process any pending model modifications.
    model.write("model.lp");
    system("cat model.lp");

    model.optimize();

    double soma=0.0;
    int i = 0;
    for (ListGraph::EdgeIt e(g); e!=INVALID; ++e) {
      lpvar[e] = x[e].get(GRB_DoubleAttr_X);
      if (lpvar[e] > 1-BC_EPS ) {
	soma += weight[e];
	cout << "Achei, x("<< vname[g.u(e)] << " , " << vname[g.v(e)] << ") = " << lpvar[e] <<"\n";
	tsp.BestCircuit[i] = g.u(e);
	tsp.BestCircuit[i+1] = g.v(e);
	i = i+2;
	
      }
    }

    cout << "Solution cost = "<< soma << endl;
    ViewTspCircuit(tsp);

  }catch (...) {
    if (tsp.BestCircuitValue < DBL_MAX) {
      cout << "Heuristic obtained optimum solution"  << endl;
      ViewTspCircuit(tsp);
      return 0;
    }else {
      cout << "Graph is infeasible"  << endl;
      return 1;
    }
  }
}