/*
* (non-Javadoc)
*
* @see net.sf.javailp.Solver#solve(net.sf.javailp.Problem)
*/
public Result solve(Problem problem) {
Map<IloNumVar, Object> numToVar = new HashMap<IloNumVar, Object>();
Map<Object, IloNumVar> varToNum = new HashMap<Object, IloNumVar>();
try {
IloCplex cplex = new IloCplex();
initWithParameters(cplex);
for (Object variable : problem.getVariables()) {
VarType varType = problem.getVarType(variable);
Number lowerBound = problem.getVarLowerBound(variable);
Number upperBound = problem.getVarUpperBound(variable);
double lb = (lowerBound != null ? lowerBound.doubleValue() : Double.NEGATIVE_INFINITY);
double ub = (upperBound != null ? upperBound.doubleValue() : Double.POSITIVE_INFINITY);
final IloNumVarType type;
switch (varType) {
case BOOL:
type = IloNumVarType.Bool;
break;
case INT:
type = IloNumVarType.Int;
break;
default: // REAL
type = IloNumVarType.Float;
break;
}
IloNumVar num = cplex.numVar(lb, ub, type);
numToVar.put(num, variable);
varToNum.put(variable, num);
}
for (Constraint constraint : problem.getConstraints()) {
IloLinearNumExpr lin = cplex.linearNumExpr();
Linear linear = constraint.getLhs();
convert(linear, lin, varToNum);
double rhs = constraint.getRhs().doubleValue();
switch (constraint.getOperator()) {
case LE:
cplex.addLe(lin, rhs);
break;
case GE:
cplex.addGe(lin, rhs);
break;
default: // EQ
cplex.addEq(lin, rhs);
}
}
if (problem.getObjective() != null) {
IloLinearNumExpr lin = cplex.linearNumExpr();
Linear objective = problem.getObjective();
convert(objective, lin, varToNum);
if (problem.getOptType() == OptType.MIN) {
cplex.addMinimize(lin);
} else {
cplex.addMaximize(lin);
}
}
for (Hook hook : hooks) {
hook.call(cplex, varToNum);
}
if (!cplex.solve()) {
cplex.end();
return null;
}
final Result result;
if (problem.getObjective() != null) {
Linear objective = problem.getObjective();
result = new ResultImpl(objective);
} else {
result = new ResultImpl();
}
for (Entry<Object, IloNumVar> entry : varToNum.entrySet()) {
Object variable = entry.getKey();
IloNumVar num = entry.getValue();
VarType varType = problem.getVarType(variable);
double value = cplex.getValue(num);
if (varType.isInt()) {
int v = (int) Math.round(value);
result.putPrimalValue(variable, v);
} else {
result.putPrimalValue(variable, value);
}
}
cplex.end();
return result;
} catch (IloException e) {
e.printStackTrace();
}
return null;
}
