Re: [rules-users] Continuous Planning values for task planning

Hi Geoffrey, Thanks for your reply. other task forces occupies the user at that time)? Math.max((endTime of task before B), (endTime of task A + 7 minutes))? task B starts 8 minutes after task A and the user doing no task that last minute. Yes, the starting time of B = Math.max((endTime of task before B), (endTime of task A + 7mins)) as long as it is smaller than (endTime of task A + 8mins). Yes, it is pointless to investigate the solutions where task B starts 8 minutes after task A and the user doing no task that last minute. The 8 minute is just a constraint that the task in between tasks A and B cannot take longer than 7:59s. I am thinking that maybe instead of using time itself as the planning variable, we would use time just to determine the Hard and Soft scores. So if Task B is scheduled after Task A + 8mins by the solver, then it inflicts on the hard score. Similarly if Task B is scheduled before Task A + 7 mins. Does my reasoning make sense in any way? thanks, Josef On 24 July 2012 20:46, Geoffrey De Smet <ge0ffrey.spam(a)gmail.com&gt; wrote: > > Op 23-07-12 16:26, Josef Bajada schreef: > > Hi Geoffrey, > > Well I want to leave 'space' between tasks in the situations where there > are hard constraints that require me to put this space. > > This makes the chaining technique harder to model, but I wouldn't write it > off yet. > > > As a simple example: > > Task A: Put pasta in boiling water (duration 40 seconds) > Task B: Take pasta out of boiling water (duration 50 seconds, cannot start > before 7 mins after Task A finishes, cannot start after 8 mins after Task A > finishes) > > other task forces occupies the user at that time)? > Math.max((endTime of task before B), (endTime of task A + 7 minutes))? > If we can say that, it's pointless to investigate the solutions where task > B starts 8 minutes after task A and the user doing no task that last minute. > If we can say that, then chaining can calculate the the starting time of a > task on the fly differently. > > Task C: Chop vegetables (duration 2 minutes). > > This will evidently leave some gaps. The ideal result from the solver > should be: > > Task A: at time 0 (ends at 40s) > Task C: at time 41s (ends at 2:41) > Task B: at time 7:40 > > There is a gap between C and B which is OK. > > If another Task is added to the story: > Task D: Prepare sauce (duration 7 minutes) > > I would want the following result: > > Task A: at time 0 (ends at 40s) > Task D: at time 41s (ends 7:41s) > Task B: at time 8:42s (ends 9:32s) > Task C: at time 9:33s (ends 11:33s) > > Task C can actually take place before Task A too. > > I still need to read and understand the chaining functionality properly. > Do you think it would allow me to achieve the above? > > I don't know. > But using continuous variables in a search problem such as this that > smells discrete with discrete constraints (A must start before B, ...), > could blow up the search space unnecessarily. > > If you want to look into using continuous variables: the support for it is > limited currently. > you can reuse the Drools Planner metaheuristic algorithms (including > termination, score, ...), but there's no decent generic move factory > support for continuous variables yet. > So you 'll have to write a custom MoveFactory that creates a limited > subset of moves. > Also, construction heuristics can't handle continuous variables yet, so > you 'll have to write a custom SolutionIntializer. > There are examples with a custom MoveFactory and a custom > SolutionIntializer where you can copy paste from, but none with continuous > variables at the moment. > > thanks, > > Josef > > > > On 22 July 2012 20:05, Geoffrey De Smet <ge0ffrey.spam(a)gmail.com&gt; wrote: > >> Presuming that you don't want to leave space between tasks, you can >> design your model differently by using the "chained" functionality: >> it will be far more efficient and the planning variable won't be >> continuous. >> >> Let's presume you're scheduling Tasks to Persons. >> >> @PlanningEntity >> class Task implements TaskOrPerson { >> >> ... >> >> @PlanningVariable(chained = true) >> @ValueRanges({ >> @ValueRange(type = ValueRangeType.FROM_SOLUTION_PROPERTY, >> solutionProperty = "taskList"), >> @ValueRange(type = ValueRangeType.FROM_SOLUTION_PROPERTY, >> solutionProperty = "personList", >> excludeUninitializedPlanningEntity = true)}) >> public TaskOrPerson getPreviousTaskOrPerson() { >> return previousTaskOrPerson; >> } >> >> public int getDuration() { >> return duration; >> } >> >> public int getStartingTime() { >> int startingTime = 0; >> TaskOrPerson taskOrPerson = getPreviousTaskOrPerson(); >> while (taskOrPerson instanceof Task) { // Every chain is >> guarantee to end up with an anchor (= Person) >> startingTime += ((Task) taskOrPerson).getDuration(); >> taskOrPerson = ((Task) >> taskOrPerson).getPreviousTaskOrPerson() >> } >> return startingTime; >> } >> >> } >> >> class Person implements TaskOrPerson { >> >> } >> >> For a good example, take a look at the VehicleRouting example. >> For more info about chaining, in the manual see section 4.3.4.2.6. Chained >> >> http://docs.jboss.org/drools/release/5.4.0.Final/drools-planner-docs/html... >> >> Op 22-07-12 18:00, Josef Bajada schreef: >> >> Hi, >> >> I am new to Drools and Drools Planner, so apologies if I am asking >> anything obvious. >> >> My objective is to implement a simple (for now) planner which schedules >> tasks according to 2 main criteria: >> - Their duration (in seconds) >> - Their dependencies on other tasks (e.g. Hard Constraint that Task B has >> to start between 180 and 200 seconds after Task A finishes). >> >> Since there are gaps between dependent tasks as part of the hard >> constraints other tasks can be fitted in between dependent tasks. >> So the Solver needs to find the optimal start time for each task that >> satisfies the hard constraints, and in the shortest total timeline possible >> to complete all tasks (soft constraint). >> >> The main problem I am finding is that this start time, which is >> essentially the planning variable is a continuous variable. >> Chapter 4 of the Drools documentation mentions very briefly (Section >> 4.3.4.1) that planning variables can be continuous, but there does not >> seem to be any more details about how to achieve this. >> >> Even if the planning variable was discrete (say bins of 5 second >> intervals), there is no upper bound as such. >> >> How is it best to handle such planning variables in Drools Planner? >> >> thanks, >> josef >> >> >> >> >> _______________________________________________ >> rules-users mailing listrules-users@lists.jboss.orghttps://lists.jboss.org/mailman/listinfo/rules-users >> >> >> -- >> With kind regards, >> Geoffrey De Smet >> >> >> _______________________________________________ >> rules-users mailing list >> rules-users(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/rules-users >> >> > > > _______________________________________________ > rules-users mailing listrules-users@lists.jboss.orghttps://lists.jboss.org/mailman/listinfo/rules-users > > > -- > With kind regards, > Geoffrey De Smet > > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > >