使用流控制更改一些數據並在 CPLEX 中解析

Question

我未能在每次迭代中更改 due_time 的值。 如何更改我的代碼？

ct9: // due time 
forall(k in orders, j in orders_nodes[k]:j in k.dest) 
    arrival_time[k][j]<=due_time;



main {
    thisOplModel.generate();
    var new_due = 25;
    
    while( new_due <50)
    {  ...

    new_due ++;
    thisOplModel.ct9.UB = new_due;
    }
 }

CPLEX 告訴我 ct9 的 UB 未定義。 ct9右側的due_time是UB嗎？

我也試過thisOplModel.due_time ++; 但失敗了。 你有什么主意嗎？

Answer 1

改寫

 // due time 
 forall(k in orders, j in orders_nodes[k]) 
     ct9: if (j in k.dest) arrival_time[k][j]<=due_time;

加上而不是

thisOplModel.ct9.UB 

你應該索引 ct9

thisOplModel.ct9[k][j].UB = new_due;

流控制和使優化變得簡單中的增量更改的小例子

int nbKids=300;
float costBus40=500;
float costBus30=400;
 
dvar int+ nbBus40;
dvar int+ nbBus30;
 
minimize
 costBus40*nbBus40  +nbBus30*costBus30;
 
subject to
{
 ctKids:40*nbBus40+nbBus30*30>=nbKids;
}

execute
{
writeln("nbBus40 = ",nbBus40);
writeln("nbBus30 = ",nbBus30);
}

main
{
thisOplModel.generate();

cplex.solve();
thisOplModel.postProcess();

//now 350 kids instead of 300
writeln("now 350 kids instead of 300");
    
thisOplModel.ctKids.LB=350;

cplex.solve();
thisOplModel.postProcess();


// no more than 4 buses 40 seats
writeln("no more than 4 buses 40 seats");

thisOplModel.nbBus40.UB=4;

cplex.solve();
thisOplModel.postProcess();

// change the objective so that cost for 40 seats is 450
// and remove the limit on the number of buses 40 seats

writeln("change the objective so that cost for 40 seats is 450");
writeln("and remove the limit on the number of buses 40 seats");    

thisOplModel.nbBus40.UB=1000;
cplex.setObjCoef(thisOplModel.nbBus40,450);
cplex.setObjCoef(thisOplModel.nbBus30,400);

cplex.solve();
thisOplModel.postProcess();

 


}

這使

nbBus40 = 6
nbBus30 = 2
now 350 kids instead of 300
nbBus40 = 8
nbBus30 = 1
no more than 4 buses 40 seats
nbBus40 = 2
nbBus30 = 9
change the objective so that cost for 40 seats is 450
and remove the limit on the number of buses 40 seats
nbBus40 = 8
nbBus30 = 1

對於您的循環，請參見

int nbKids=300;
float costBus40=500;
float costBus30=400;

range r=1..4;
 
dvar int+ nbBus40[i in r][j in r];
dvar int+ nbBus30[i in r][j in r];
 
minimize
 sum(i,j in r)(costBus40*nbBus40[i][j]  +nbBus30[i][j]*costBus30);
 
subject to
{
 forall(i,j in r)ctKids: if (i!=j) 40*nbBus40[i][j]+nbBus30[i][j]*30>=nbKids;
}

execute
{
writeln("nbBus40 = ",nbBus40);
writeln("nbBus30 = ",nbBus30);
}

main
{
thisOplModel.generate();

cplex.solve();
thisOplModel.postProcess();

//now 350 kids instead of 300
writeln("now 350 kids instead of 300");
    
for(i in thisOplModel.r) for(j in thisOplModel.r) if (i!=j) thisOplModel.ctKids[i][j].LB=350;

cplex.solve();
thisOplModel.postProcess();






 


}

Answer 2

謝謝你的分享。 我仍然無法更改 ct9 的上行，CPLEX 告訴我索引是可變的。 索引 k 和 j 在數據文檔中給出。 你知道為什么嗎？

或者我認為我們可以更改每個訂單的到期時間，而不是更改 ct9 的上行。 然后我寫了這些代碼。 我習慣了 output 第一單的到期時間。 是的。 它改變了，但目標沒有改變。 增加到期時間時，目標應該更小：當我將 ct9 的騎行側更改為等於和小於 45 時，目標應該更小。比如：

ct9:// due time 
forall(k in orders, j in k.dest) 
arrival_time[k][j]<=45;

你知道如何更正這些代碼嗎？

主要的 {

    var ofile = new IloOplOutputFile("due time and threshold.txt");
    var new_due = 40;
    var due_max = 45; 

    writeln("due time changes from  "+ new_due+" to  "+due_max);

    
    while( new_due <= due_max )
    {           
        ofile.writeln("For due time = "+new_due);
        ofile.writeln("**************************************");
        
        thisOplModel.generate();
        cplex.solve()
        thisOplModel.postProcess();
        
        
        if (cplex.getCplexStatus())
        {
            for (var k in thisOplModel.orders)
            {
                                                    
               ofile.writeln(" *  for order "+ k.no+"    "+k.volume);     
                for( var s in thisOplModel.services)
                    {                   
                    for( var a in thisOplModel.orders_arcs[k])
                        { if (thisOplModel.x[k][a][s]>0 && a==s.a)
                            { 
                            ofile.writeln(" via arc  "+ a +" by  "+ s.keynumb);
            
                             }  
                        }
                     }                                                                       
                 
                 ofile.writeln("    ");     
                 ofile.writeln("    ");   
             }   
             writeln("objective is "+thisOplModel.WH_income+"    ");    
             writeln("    ");     
                     
         }
         else
        { 
            writeln("No solution"); 
            writeln(cplex.getCplexStatus());
            break;
        }
        
        new_due ++;
        
        for (var k=1; k<=thisOplModel.N_order;k++)
        {   
            temp_order = Opl.item(thisOplModel.orders,k-1); 
            temp_order.due_time = new_due;
            if (k==1)
            {writeln("new due time for next iteration is "+temp_order.due_time);
             writeln("    "); }
        }   
        
    
    }