Originally posted by: Ximenes

Hello,everyone,when I used C++ calling CPLEX to solve my MICQP, I got an error saying "using empty handle". I had checked the following code several times but still don't know the source error. So I want to get help from you.
//////////////////////////////////////////////////////////////////////
#include <ilcplex/ilocplex.h>

ILOSTLBEGIN

typedef IloArray<IloBoolVarArray> BoolVarMatrix;
int main(int argc, char** argv) {
IloEnv env;

try {
IloInt i, j, k;
IloInt nOrder;

const char* filename;
if (argc > 1)
filename = argv[1];
else
filename = "C:\\Users\\Ximenes\\Desktop\\5月31\\try.dat";
ifstream f(filename, ios::in);
if (!f) {
cerr << "No such file: " << filename << endl;
throw(1);
}

//C:\Users\Ximenes\Desktop\5月31

IloNum T;
IloNumArray P1(env);
IloNumArray P2(env);
IloNumArray R(env);

f >> T;
f >> P1;
f >> P2;
f >> R;

nOrder = R.getSize();
IloModel model(env);

// Create start variables
IloInt K;
BoolVarMatrix x(env, nOrder);
for (i = 0; i < nOrder; i++) {
x[i] = IloBoolVarArray(env, nOrder);
}

BoolVarMatrix z(env, nOrder);
for (i = 0; i < nOrder; i++) {
z[i] = IloBoolVarArray(env, nOrder);
}

IloBoolVarArray y(env,nOrder);
IloNumVarArray W(env,nOrder,0.0,T);
IloNumVarArray I(env,nOrder,0.0,T);

// 第1个约束
for (i = 0; i < nOrder; i++) {
IloExpr expr(env);
for(j=0;j<i;j++)
expr+=x[i][j];
for(j=i+1;j<nOrder;j++)
expr+=x[i][j];
model.add(expr==y[i]);
expr.end();
}
//第2个约束
for (j = 0; j < nOrder; j++) {
IloExpr expr(env);
for(i=0;i<j;i++)
expr+=x[i][j];
for(i=j+1;i<nOrder;i++)
expr+=x[i][j];
model.add(expr==y[j]);
expr.end();
}
//时间约束
IloExpr expr(env);
for(j=0;j<nOrder;j++) {
expr+=z[j][0]*P1[j];
expr+=P2[j]*y[j];
expr+=I[j];
}
model.add(expr<=T);
expr.end();

//W.I约束
for(k=0;k<nOrder-1;k++){
IloExpr expr(env);
for(j=0;j<nOrder;j++){
expr+=z[j][k]*P2[j];
expr-=z[j]k+1*P1[j];
}
expr+=W[k];
expr-=Wk+1;
expr+=I[k];
model.add(expr==0);
expr.end();
}

//Z约束
for(j=0;j<nOrder;j++){ //订单j最多可能被安排在一个位置
IloExpr expr(env);
for(k=0;k<nOrder;k++)
expr+=z[j][k];
model.add(expr<=1);
expr.end();
}

for(k=0;k<nOrder;k++){ //位置k最多被安排一个订单
IloExpr expr(env);
for(j=0;j<nOrder;j++)
expr+=z[j][k];
model.add(expr<=1);
expr.end();
}
for(j=0;j<nOrder;j++){//Z_jk≤y_j,j=1,2,…,n;k=1,2,…,K
for(k=0;k<nOrder;k++)
model.add(z[j][k]<=y[j]);
}

IloExpr expr1(env);//K等于y[j]连加的和，表示选择的订单数
for(j=0;j<nOrder;j++)
expr1+=y[j];
model.add(K==expr);
expr1.end();

// 最大化目标函数

IloExpr profitSum(env);
for (j = 0; j < nOrder; j++) {
profitSum +=R[j]*y[j];
}
model.add(IloMaximize(env, profitSum));
profitSum.end();

//计算及输出
IloCplex cplex(env);

cplex.extract(model);

cplex.setParam(IloCplex::MIPEmphasis, 4);

if (cplex.solve()) {
cout << " Optimal Value = " << cplex.getObjValue() << endl;
}
}
catch (IloException& ex) {
cerr << "Error: " << ex << endl;
}
catch (...) {
cerr << "Error" << endl;
}
env.end();
&IloAlgorithm::getStatus;
system("pause");
return 0;
}
/*

10
2, 3, 5
1, 3, 2
13，6, 7 */
/////////////////////////////////////////////////////////////////////////////////////
Thank you so much.
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

That is a lot of code to look through. Could you please tell us which is the exact statement that causes the error message?
The first thing I would try is to double check whether the values T, P1, P2, and R that your read from f are as expected. Just print out T and the arrays and double check that they contain the expected data.
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: Ximenes

Thank you for your considerate reply. I've found the source error. I had not define the bound of t][. To your suggestion of input of the data, I am sure it has no problem.
Now another problem arises. I can easily know the optimal value since the data is very simple since I take it for checking. But when I debug the revised code, the optimal is 0.
Can you help me?
Thank you in advance.
////////////////////////////////////////////////////////////////////////////////////////////////////
#include <ilcplex/ilocplex.h>

ILOSTLBEGIN

typedef IloArray<IloBoolVarArray> BoolVarMatrix;
typedef IloArray<IloIntVarArray> IntVarMatrix;

int main(int argc, char** argv) {
IloEnv env;

try {
IloInt i, j, k;
IloInt nOrder;

const char* filename;
if (argc > 1)
filename = argv[1];
else
filename = "C:\\Users\\Ximenes\\Desktop\\5月31\\try.dat";
ifstream f(filename, ios::in);
if (!f) {
cerr << "No such file: " << filename << endl;
throw(1);
}

//C:\Users\Ximenes\Desktop\5月31

IloNum T;
IloNumArray P1(env);
IloNumArray P2(env);
IloNumArray R(env);

f >> T;
f >> P1;
f >> P2;
f >> R;

nOrder = R.getSize();
IloModel model(env);

// Create start variables
BoolVarMatrix x(env, nOrder);
for (i = 0; i < nOrder; i++) {
x[i] = IloBoolVarArray(env, nOrder);
}

BoolVarMatrix z(env, nOrder);
for (i = 0; i < nOrder; i++) {
z[i] = IloBoolVarArray(env, nOrder);
}

IntVarMatrix t(env, nOrder);
for (i = 0; i < nOrder; i++) {
t[i] = IloIntVarArray(env, nOrder,0,1);
}

IloBoolVarArray y(env,nOrder);
IloNumVarArray W(env,nOrder,0.0,T);
IloNumVarArray I(env,nOrder-1,0.0,T);

// 第1个约束
for (i = 0; i < nOrder; i++) {
IloExpr expr(env);
for(j=0;j<i;j++)
expr+=x[i][j];
for(j=i+1;j<nOrder;j++)
expr+=x[i][j];
model.add(expr==y[i]);
expr.end();
}
//第2个约束
for (j = 0; j < nOrder; j++) {
IloExpr expr(env);
for(i=0;i<j;i++)
expr+=x[i][j];
for(i=j+1;i<nOrder;i++)
expr+=x[i][j];
model.add(expr==y[j]);
expr.end();
}

for(i=0;i<nOrder;i++){
for(j=0;j<nOrder;j++)
model.add(t[j][k]==(z[j][k]+y[j]/2));
}
//时间约束
IloInt last=nOrder-1;
IloExpr expr(env);
for(j=0;j<last;j++) {
expr+=t[j][0]*P1[j];
expr+=I[j];
expr+=P2[j]*y[j];
}
expr+=tlast[0]*P1last;
expr+=P2last*ylast;
model.add(expr<=T);
expr.end();

//W.I约束
for(k=0;k<last;k++){
IloExpr expr(env);
for(j=0;j<nOrder;j++){
expr+=t[j][k]*P2[j];
expr-=t[j]k+1*P1[j];
}
expr+=W[k];
expr-=Wk+1;
expr+=I[k];
model.add(expr==0);
expr.end();
}

//Z加和等于1约束
for(j=0;j<nOrder;j++){
IloExpr expr(env);
for(k=0;k<nOrder;k++)
expr+=z[j][k];
model.add(expr==1);
expr.end();
}

for(k=0;k<nOrder;k++){
IloExpr expr(env);
for(j=0;j<nOrder;j++)
expr+=z[j][k];
model.add(expr==1);
expr.end();
}
// 最大化目标函数

IloExpr profitSum(env);
for (j = 0; j < nOrder; j++) {
profitSum +=R[j]*y[j];
}
model.add(IloMaximize(env, profitSum));
profitSum.end();

//计算及输出
IloCplex cplex(env);

cplex.extract(model);

cplex.setParam(IloCplex::MIPEmphasis, 4);

if (cplex.solve()) {
cout << " Optimal Value = " << cplex.getObjValue() << endl;
}
}
catch (IloException& ex) {
cerr << "Error: " << ex << endl;
}
catch (...) {
cerr << "Error" << endl;
}
env.end();
system("pause");
return 0;
}
////////////////////////////////////////////////////////////////////////////////////////////////
The data is listed as follow.
10
2, 3, 5
1, 3, 2
3，6, 7
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

First thing you should do is to print out the model using one of the following lines:

std::cout << model << std::endl; cplex.exportModel(model, 
"model.lp");

The second line exports the model to file model.lp which is a human readable file format and can be read using any text editor. Then check whether the model looks as expected.
I see these lines in your code:

for(i=0;i<nOrder;i++)
{ 

for(j=0;j<nOrder;j++) model.add(t[j][k]==(z[j][k]+y[j]/2)); 
}

As far as I can see variable 'k' is never initialized before that block. So the value of 'k' is just random here. Doesn't your compiler warn about that? Maybe you only need to properly initialize 'k' to get the model right?
Some technical advice (feel free to ignore):
1. You should crank up the compiler's warning flags so that it warns you about using uninitialized values (like 'k' above).
2. In C++ you can write

for (

int i = ...) 
{ ... 
} 

for (

int i = ...) 
{ ... 
}

instead of

int i; 

for (i = ...) 
{ ... 
} 

for (i = ...) 
{ ... 
}

The first syntax is preferred as it limits the scope of variable 'i'. Had you used the first syntax you would have immediately noticed your error since there would not have been a 'k' variable defined.

I hope this helps.
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: Ximenes

Oh,thank you so much for your considerate reply, Daniel. I find it most useful of being informed by you with the two following lines:

std::cout << model << std::endl;
cplex.exportModel(model, "model.lp");

Because I didn't know that I can read the model extracted by CPLEX.

But when I post the two lines in the following position of the codes, it underlines red wavy lines "model, "model.lp". Can you tell me why?
Thank you so much.
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

> Oh,thank you so much for your considerate reply, Daniel. I find it most useful of being informed by you with the two following lines:
>
> std::cout << model << std::endl;
> cplex.exportModel(model, "model.lp");
>
> Because I didn't know that I can read the model extracted by CPLEX.
>
> But when I post the two lines in the following position of the codes, it underlines red wavy lines "model, "model.lp". Can you tell me why?
> Thank you so much.
>
Sorry, no clue. Is that considered an error? Is it possible that it performs spell checking on the string "model.lp"? That would of course fail as "model.lp" is not an English sentence.
Is your IloModel instance called 'model' or did you use a different name for that? Then you would have no 'model' variable to print and should adapt the code appropriately.
#CPLEXOptimizers
#DecisionOptimization