Hi Geoffrey,<div><br></div><div>Well I want to leave 'space' between tasks in the situations where there are hard constraints that require me to put this space.</div><div><br></div><div>As a simple example:</div><div>
<br></div><div>Task A: Put pasta in boiling water (duration 40 seconds)</div><div>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)</div>
<div>Task C: Chop vegetables (duration 2 minutes).</div><div><br></div><div>This will evidently leave some gaps. The ideal result from the solver should be:</div><div><br></div><div>Task A: at time 0 (ends at 40s)</div><div>
Task C: at time 41s (ends at 2:41)</div><div>Task B: at time 7:40</div><div><br></div><div>There is a gap between C and B which is OK. </div><div><br></div><div>If another Task is added to the story:</div><div><div>Task D: Prepare sauce (duration 7 minutes)</div>
</div><div><br></div><div>I would want the following result:</div><div><br></div><div>Task A: at time 0 (ends at 40s)</div><div>Task D: at time 41s (ends 7:41s)</div><div>Task B: at time 8:42s (ends 9:32s)</div><div>Task C: at time 9:33s (ends 11:33s)</div>
<div><br></div><div>Task C can actually take place before Task A too. </div><div><br></div><div>I still need to read and understand the chaining functionality properly. Do you think it would allow me to achieve the above?</div>
<div><br></div><div>thanks,</div><div><br></div><div>Josef</div><div><br></div><div><br><br><div class="gmail_quote">On 22 July 2012 20:05, Geoffrey De Smet <span dir="ltr"><<a href="mailto:ge0ffrey.spam@gmail.com" target="_blank">ge0ffrey.spam@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
Presuming that you don't want to leave space between tasks, you can
design your model differently by using the "chained" functionality:<br>
it will be far more efficient and the planning variable won't be
continuous.<br>
<br>
Let's presume you're scheduling Tasks to Persons.<br>
<br>
@PlanningEntity<br>
class Task implements TaskOrPerson {<br>
<br>
...<br>
<br>
@PlanningVariable(chained = true)<br>
@ValueRanges({<br>
@ValueRange(type =
ValueRangeType.FROM_SOLUTION_PROPERTY, solutionProperty =
"taskList"),<br>
@ValueRange(type =
ValueRangeType.FROM_SOLUTION_PROPERTY, solutionProperty =
"personList",<br>
excludeUninitializedPlanningEntity = true)})<br>
public TaskOrPerson getPreviousTaskOrPerson() {<br>
return previousTaskOrPerson;<br>
}<br>
<br>
public int getDuration() {<br>
return duration;<br>
}<br>
<br>
public int getStartingTime() {<br>
int startingTime = 0;<br>
TaskOrPerson taskOrPerson = getPreviousTaskOrPerson();<br>
while (taskOrPerson instanceof Task) { // Every chain is
guarantee to end up with an anchor (= Person)<br>
startingTime += ((Task) taskOrPerson).getDuration();<br>
taskOrPerson = ((Task)
taskOrPerson).getPreviousTaskOrPerson()<br>
}<br>
return startingTime;<br>
}<br>
<br>
}<br>
<br>
class Person implements TaskOrPerson {<br>
<br>
}<br>
<br>
For a good example, take a look at the VehicleRouting example.<br>
For more info about chaining, in the manual see section 4.3.4.2.6.
Chained<br>
<a href="http://docs.jboss.org/drools/release/5.4.0.Final/drools-planner-docs/html_single/index.html" target="_blank">http://docs.jboss.org/drools/release/5.4.0.Final/drools-planner-docs/html_single/index.html</a><br>
<br>
<div>Op <a href="tel:22-07-12%2018" value="+35622071218" target="_blank">22-07-12 18</a>:00, Josef Bajada
schreef:<br>
</div>
<blockquote type="cite"><div><div class="h5">Hi,
<div><br>
</div>
<div>I am new to Drools and Drools Planner, so apologies if I am
asking anything obvious.</div>
<div><br>
</div>
<div>My objective is to implement a simple (for now) planner which
schedules tasks according to 2 main criteria:</div>
<div>- Their duration (in seconds)</div>
<div>- Their dependencies on other tasks (e.g. Hard Constraint
that Task B has to start between 180 and 200 seconds after Task
A finishes).</div>
<div><br>
</div>
<div>Since there are gaps between dependent tasks as part of the
hard constraints other tasks can be fitted in between dependent
tasks.</div>
<div>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).</div>
<div><br>
</div>
<div>The main problem I am finding is that this start time, which
is essentially the planning variable is a continuous variable. </div>
<div>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.</div>
<div><br>
</div>
<div>Even if the planning variable was discrete (say bins of 5
second intervals), there is no upper bound as such.</div>
<div><br>
</div>
<div>How is it best to handle such planning variables in Drools
Planner?</div>
<div><br>
</div>
<div>thanks,<br>
josef</div>
<div><br>
</div>
<div><br>
</div>
<br>
<fieldset></fieldset>
<br>
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<br>
<pre cols="72">--
With kind regards,
Geoffrey De Smet</pre>
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