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package samples.integer;
import samples.AbstractProblem;
import solver.Solver;
import solver.constraints.IntConstraintFactory;
import solver.search.strategy.IntStrategyFactory;
import solver.variables.IntVar;
import solver.variables.Task;
import solver.variables.VariableFactory;
import util.ESat;
/**
* @author Gregy4
*/
public class CumulativeSample2 extends AbstractProblem {
public static int NUM_OF_TASKS = 1000;
public static int HORIZON = 20000;
IntVar[] starts, ends;
IntVar maxEnd;
@Override
public void createSolver(){
solver = new Solver("schedule");
}
@Override
public void buildModel(){
// build variables
starts = new IntVar[NUM_OF_TASKS];
ends = new IntVar[NUM_OF_TASKS];
IntVar duration = VariableFactory.fixed(10, solver);
maxEnd = VariableFactory.bounded("maxEnd", 0, HORIZON, solver);
IntVar[] res = new IntVar[NUM_OF_TASKS];
Task[] tasks = new Task[NUM_OF_TASKS];
for (int iTask=0; iTask < NUM_OF_TASKS; ++iTask) {
starts[iTask] = VariableFactory.bounded("start" + iTask, 0, HORIZON, solver);
ends[iTask] = VariableFactory.bounded("ends" + iTask, 0, HORIZON, solver);
tasks[iTask] = VariableFactory.task(starts[iTask], duration, ends[iTask]);
res[iTask] = VariableFactory.fixed(1 , solver);
}
// post a cumulative constraint
solver.post(IntConstraintFactory.cumulative(tasks, res, VariableFactory.fixed(1, solver), false));
// maintain makespan
solver.post(IntConstraintFactory.maximum(maxEnd, ends));
// add precedences
int prevIdx = -1;
for (int iTask=999; iTask >= 0; --iTask) {
if (prevIdx != -1) {
if (iTask % 2 == 0 || iTask % 3 == 0) {
solver.post(IntConstraintFactory.arithm(starts[iTask], ">=", ends[prevIdx]));
}
}
prevIdx = iTask;
}
}
@Override
public void configureSearch(){
solver.set(IntStrategyFactory.lexico_LB(starts));
}
@Override
public void solve(){
solver.findSolution();
}
@Override
public void prettyOut(){
if (solver.isFeasible() == ESat.TRUE) {
System.out.println("solution found");
}
}
public static void main(String[] args){
new CumulativeSample2().execute(args);
}
}