Calback in C++ : list of arguments
AnsweredI'm trying to use a callback to add a cut that equals a Gurobi expression, which sums a variable, at different times.
If I keep the expression in the list of callback arguments, I get an error message related to the arguments (they don't match!). Once I remove it (GRBQuadExpr) the optimization is done without running the callback.
I appreciate any help for which I thank you in advance!
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Could you please share a minimal reproducible example of your code describing the issue?
Please also post the exact error you get when trying to execute your code.
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Hallo Jaromil,
Please find below the instantiation of part of the callback, that will be applied at the solution node. After I commented Ecurrent expression, then the optimization runs, without running the callback.
class subproblem1 : public GRBCallback {
public:
int *Pwind;
int* t_D_f;
GRBVar** Pbss;
GRBVar** Pbssd;
GRBQuadExpr** Ecurrent;
subproblem1(int *xPwind,int *xt_D_f,GRBVar**xPbss,GRBVar**xPbssd){// numvars_sp1 = xnumvars;
Pwind = xPwind;
t_D_f = xt_D_f;
Pbss = xPbss;
Pbssd = xPbssd;
//Ecurrent = xEcurrent;
}
protected:void callback() {
try {
if (where == GRB_CB_MIPSOL) {// Query Zllower builds Zupper and compares its difference to epsilon tolerance
double zl = getDoubleInfo(GRB_CB_MIPSOL_OBJ);
int nodecnt = (int)getDoubleInfo(GRB_CB_MIPSOL_NODCNT); // solution at node .
double obj = getDoubleInfo(GRB_CB_MIPSOL_OBJ);
int solcnt = getIntInfo(GRB_CB_MIPSOL_SOLCNT);
int Kb = 0;
int kf = 0;
Kb= T - 1; //T is an extern const int variable//do something with the Gurobi expression to get the same Gurobi variables to count.
while (! Kb == 0) {
for (int bess = 0; bess < N_BESS; bess++) {p=Kb;
while (! p==Kb-6){
addCut(Ecurrent[bess][p] >= Ecurrent[bess][p-1]);
p -=1;
}
kf = p;
while (! kf==p+6){
addCut(Ecurrent[bess][kf] .>= Ecurrent[bess][kf + 1]);
kf +=1;
}Kb - = 1;
}
}
}}
} catch (GRBException e) {
cout << "Error number: " << e.getErrorCode() << endl;
cout << e.getMessage() << endl;
}
catch (...) {
cout << "Error during callback" << endl;
}}
};Thanks in advance!
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What is the exact error you get when you run with your callback?
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Hallo Jaromil,
I think we mismatch answers and questions please find above the piece of my callback.
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These conditions
while (! Kb == 0) {
...
while (! p==Kb-6){
...
while (! kf==p+6){look strange. Did you mean
while ( Kb != 0) {
...
while (p != Kb-6){
...
while (kf != p+6){or (equivalently)
while (! (Kb == 0)) {
...
while (! (p==Kb-6)){
...
while (! (kf==p+6)){Your current code might be misunderstood as \(\texttt{(!Kb) == 0}\).
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Could you also point me to which arguments don't match according to the error you see?
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The constructor
subproblem1(int *xPwind,int *xt_D_f,GRBVar**xPbss,GRBVar**xPbssd)
is missing an argument for \(\texttt{Ecurrent}\).
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Hallo Jaromil,
Yeah ... because if I join it then I get the error message about the list of arguments.
"subproblem1 cb = subproblem1(P_wind,t_D_f,Pbss,Pbssd,Ecurrent);
Severity Code Line Description Project File
Error (active) E0289 1626 no instance of constructor "subproblem1::subproblem1" matches the argument list "0 -
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Hi Alessandra,
The argument \(\texttt{GRBQuadExpr** Ecurrent}\) is missing in the constructor \(\texttt{subproblem1}\).
Does the following work?
class subproblem1 : public GRBCallback {
public:
int *Pwind;
int* t_D_f;
GRBVar** Pbss;
GRBVar** Pbssd;
GRBQuadExpr** Ecurrent;
subproblem1(int *xPwind, int *xt_D_f,GRBVar **xPbss, GRBVar **xPbssd, GRBQuadExpr **xEcurrent){
// numvars_sp1 = xnumvars;
Pwind = xPwind;
t_D_f = xt_D_f;
Pbss = xPbss;
Pbssd = xPbssd;
Ecurrent = xEcurrent;
}
protected:
...Best regards,
Jaromił0 -
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I already had noted my mistake but Thanks a lot!
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