Originally posted by: lushengshao

today, i used cplex to solve my model, and wanted to conduct sensitivity analysis about the coefficient of variables in the objective and the RHS.when i wrote my program according to the java reference, the following error information was shown. here is the errors.

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Concert exception caught 'ilog.cplex.CpxException: CPLEX Error 1217: No solution exists.
' caught
ilog.cplex.CpxException: CPLEX Error 1217: No solution exists.

at ilog.cplex.CplexI.CALL(CplexI.java:3754)
at ilog.cplex.CplexI._boundsa(CplexI.java:4983)
at ilog.cplex.CplexI.getBoundSA(CplexI.java:2999)
at ilog.cplex.IloCplex.getBoundSA(IloCplex.java:8138)
at ilog.cplex.IloCplex.getBoundSA(IloCplex.java:8086)
at trial.Test_Continuous1.main(Test_Continuous1.java:122)

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and part of my program which is java code related to the sensitivity analysis is also listed here.

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double[] llbound = new double[T];
double[] lubound = new double[T];
double[] ulbound = new double[T];
double[] uubound = new double[T];
for (int i = 0; i < I; i++){
for(int j = 0; j < J; j++){
cplex.getBoundSA(llbound,lubound,ulbound,uubound,var_SPcaigou[i][j]);
for(int t = 0; t < T; t++){
System.out.println("SA:SPcaigoubound value=" + llbound[t]);
}
}
}

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please give me some help. thanks a lot.
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#DecisionOptimization

Originally posted by: SystemAdmin

Did you invoke cplex.solve() prior to this point? If so, did you check that a feasible solution was found?

/Paul

Mathematicians are like Frenchmen: whenever you say something to them, they translate it into their own language, and at once it is something entirely different. (Goethe)
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: lushengshao

yes, i have invoked cplex.solve() method, and got not only feasible but opitmal solution. by the way, the type of my mathematics program question is MIP, i want to know whether the cplex does not support this kind of question type. and what i should do? thanks a million.
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Originally posted by: SystemAdmin

Sensitivity analysis applies to LPs, not directly to MILPs. After solving the MILP, invoke cplex.solveFixed() and then invoke cplex.getBoundSA (for just the continuous variables).

/Paul

Mathematicians are like Frenchmen: whenever you say something to them, they translate it into their own language, and at once it is something entirely different. (Goethe)
#CPLEXOptimizers
#DecisionOptimization