private void Init()
{
horizon = factoryData.Horizon;
solver = new Solver("Factory Scheduling");
tasks = factoryData.getFlatTaskList();
taskTypes = factoryData.getTaskTypes();
taskStructures = new TaskAlternative[tasks.Length];
location2Task = new TaskAlternative[factoryData.NbWorkLocations][];
tool2Task = new List <IntervalVar> [factoryData.NbTools];
toolIntervalVar2TaskId = new List <int> [factoryData.NbTools];
tool2TransitionTimes = new List <IntVar> [factoryData.NbTools];
taskType2Tool = new List <Tool> [taskTypes.Length];
selectedTool = new List <IntVar>();
for (int tt = 0; tt < taskTypes.Length; tt++)
{
taskType2Tool[tt] = new List <Tool>();
}
foreach (Tool tool in factoryData.Tools)
{
foreach (int taskType in tool.TaskTypes)
{
taskType2Tool[taskType].Add(tool);
}
}
for (int d = 0; d < factoryData.NbWorkLocations; d++)
{
location2Task[d] = new TaskAlternative[factoryData.Locations[d].NbTasks];
}
for (int t = 0; t < factoryData.NbTools; t++)
{
tool2Task[t] = new List <IntervalVar>();
toolIntervalVar2TaskId[t] = new List <int>();
tool2TransitionTimes[t] = new List <IntVar>();
}
allToolSequences = new SequenceVar[factoryData.NbTools - 1];
startingTimes = new IntVar[factoryData.NbTools - 1][];
endTimes = new IntVar[factoryData.NbTools - 1][];
}
private void Model()
{
/* Building basic task data structures */
for (int i = 0; i < tasks.Length; i++)
{
/* Create a new set of possible IntervalVars & IntVar to decide
* which one (and only 1) is performed */
taskStructures[i] = new TaskAlternative(tasks[i]);
/* Container to use when posting constraints */
location2Task[tasks[i].LocationId][tasks[i].TaskPosition] = taskStructures[i];
/* Get task type */
int taskType = tasks[i].TaskType;
/* Possible tool for this task */
List <Tool> tools = taskType2Tool[taskType];
bool optional = tools.Count > 1;
/* List of boolean variables. If performedOnTool[t] == true then
* the task is performed on tool t */
List <IntVar> performedOnTool = new List <IntVar>();
for (int t = 0; t < tools.Count; t++)
{
/* Creating an IntervalVar. If tools.Count > 1 the intervalVar
* is *OPTIONAL* */
int toolId = tools[t].Id;
Debug.Assert(tasks[i].Durations.ContainsKey(toolId));
int duration = tasks[i].Durations[toolId];
string name = "J " + tasks[i].Id + " [" + toolId + "]";
IntervalVar intervalVar;
if (taskType == factoryData.Inspection)
{
/* We set a 0 time if the task is an inspection */
duration = 0;
intervalVar = solver.MakeFixedDurationIntervalVar(0, horizon, duration, optional, name);
IntVar start = intervalVar.SafeStartExpr(-1).Var();
intervalVar.SafeStartExpr(-1).Var().SetValues(factoryData.InspectionStarts);
}
else
{
intervalVar = solver.MakeFixedDurationIntervalVar(0, horizon, duration, optional, name);
}
taskStructures[i].Intervals.Add(intervalVar);
tool2Task[toolId].Add(intervalVar);
toolIntervalVar2TaskId[toolId].Add(i);
/* Collecting all the bool vars, even if they are optional */
performedOnTool.Add(intervalVar.PerformedExpr().Var());
}
/* Linking the bool var to a single integer variable: */
/* if alternativeToolVar == t <=> performedOnTool[t] == true */
string alternativeName = "J " + tasks[i].Id;
IntVar alternativeToolVar = solver.MakeIntVar(0, tools.Count - 1, alternativeName);
taskStructures[i].ToolVar = alternativeToolVar;
solver.Add(solver.MakeMapDomain(alternativeToolVar, performedOnTool.ToArray()));
Debug.Assert(performedOnTool.ToArray().Length == alternativeToolVar.Max() + 1);
selectedTool.Add(alternativeToolVar);
}
/* Creates precedences on a work Location in order to enforce a
* fully ordered set within the same location
*/
for (int d = 0; d < location2Task.Length; d++)
{
for (int i = 0; i < location2Task[d].Length - 1; i++)
{
TaskAlternative task1 = location2Task[d][i];
TaskAlternative task2 = location2Task[d][i + 1];
/* task1 must end before task2 starts */
/* Adding precedence for each possible alternative pair */
for (int t1 = 0; t1 < task1.Intervals.Count(); t1++)
{
IntervalVar task1Alternative = task1.Intervals[t1];
for (int t2 = 0; t2 < task2.Intervals.Count(); t2++)
{
IntervalVar task2Alternative = task2.Intervals[t2];
Constraint precedence = solver.MakeIntervalVarRelation(
task2Alternative, Solver.STARTS_AFTER_END, task1Alternative);
solver.Add(precedence);
}
}
}
}
/* Adds disjunctive constraints on unary resources, and creates
* sequence variables. */
for (int t = 0; t < factoryData.NbTools; t++)
{
string name = "Tool " + t;
if (!factoryData.Tools[t].CanPerformTaskType(factoryData.Inspection))
{
DisjunctiveConstraint ct = solver.MakeDisjunctiveConstraint(tool2Task[t].ToArray(), name);
solver.Add(ct);
allToolSequences[t] = ct.SequenceVar();
}
PostTransitionTimeConstraints(t, true);
}
/* Collecting all tasks end for makespan objective function */
List <IntVar> intervalEnds = new List <IntVar>();
for (int i = 0; i < tasks.Length; i++)
{
foreach (IntervalVar var in taskStructures[i].Intervals)
{
intervalEnds.Add(var.SafeEndExpr(-1).Var());
}
}
/* Objective: minimize the makespan (maximum end times of all tasks) */
makespan = solver.MakeMax(intervalEnds.ToArray()).Var();
objective = solver.MakeMinimize(makespan, 1);
}