11:36 p.m.
I am solving a resource allocation problem using the Planner and have run
into a few issues with the use of Local Search.
The objective is to assign tasks to a set of resources. Each task has a
start and end time and NO task should overlap each other for the same
resource. There are other rules for preference and mandate of certain tasks
to certain resources.
I am using the FIRST_FIT construction heuristic which works fine.
I have implemented a Resource Change Move which assigns a new planning
variable to my planning entity. There seem to be issues with this phase.
**Problem** -
1. While looking at the solution created at the end of the local search
phase AND comparing to the moves output in the log file. I see that there
are several instances where the log file shows a move BUT the output
solution has the entity still on the previous planning variable.
This is happening only towards the end of the phase (about last 8 steps) of
the time terminated phase.
2. I have a rule in the DRL score file which prevents overlap of allocations
of the task for the same resource. I have instances where the construction
heuristic violated this constraint. The local search solver then moved one
of the overlapping entity to another resource. However the final output
shows the constraint still EXISTS between the two entities (even though the
overlap is no longer present). As a result even though the constraints are
actually removed, the score is NOT going down as the planner constraints
still exist.
The rule used by me is as follows (Allocation is the planning entity and
resource is the variable) -
rule "noOverlapAllocations"
when
$allocation1 : Allocation($id : id, $resource : resource, $task :
task, resource != null)
$allocation2 : Allocation(id > $id, resource == $resource,
isOverlap($task), $id2 : id)
then
insertLogical(new IntConstraintOccurrence("overlapAllocation",
ConstraintType.NEGATIVE_HARD, 1, $allocation1, $allocation2));
end
Please help me resolve these issues.
Thanks
Vikram
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3:59 a.m.
Op 16-04-12 06:36, duggal schreef:
I am solving a resource allocation problem using the Planner and have
run
into a few issues with the use of Local Search.
The objective is to assign tasks to a set of resources. Each task has a
start and end time and NO task should overlap each other for the same
resource. There are other rules for preference and mandate of certain tasks
to certain resources.
I am using the FIRST_FIT construction heuristic which works fine.
Tip: FIRST_FIT is
good, FIRST_FIT_DECREASING is usually better.
I have implemented a Resource Change Move which assigns a new
planning
variable to my planning entity. There seem to be issues with this phase.
If you
upgrade to 5.4.0.CR1, you can use the generic change move and
generic swap move
http://docs.jboss.org/drools/release/5.4.0.CR1/drools-planner-docs/html_s...
**Problem** -
1. While looking at the solution created at the end of the local search
phase AND comparing to the moves output in the log file. I see that there
are several instances where the log file shows a move BUT the output
solution has the entity still on the previous planning variable.
This is happening only towards the end of the phase (about last 8 steps) of
the time terminated phase.
This sounds like a genuine bug.
Could you copy paste some logging output to show the issue more clearly?
Can you check if 5.4.0.CR1 still has the issue and create a jira:
https://issues.jboss.org/browse/JBRULES
2. I have a rule in the DRL score file which prevents overlap of
allocations
of the task for the same resource. I have instances where the construction
heuristic violated this constraint. The local search solver then moved one
of the overlapping entity to another resource. However the final output
shows the constraint still EXISTS between the two entities (even though the
overlap is no longer present). As a result even though the constraints are
actually removed, the score is NOT going down as the planner constraints
still exist.
The rule used by me is as follows (Allocation is the planning entity and
resource is the variable) -
rule "noOverlapAllocations"
when
$allocation1 : Allocation($id : id, $resource : resource, $task :
task, resource != null)
$allocation2 : Allocation(id> $id, resource == $resource,
isOverlap($task), $id2 : id)
then
insertLogical(new IntConstraintOccurrence("overlapAllocation",
ConstraintType.NEGATIVE_HARD, 1, $allocation1, $allocation2));
end
Please help me resolve these issues.
Smells like a memory corruption in
drools-core. There is one fixed for
5.4.0.CR1, so
First turn on <environmentMode>TRACE</...> and see what it outputs.
http://docs.jboss.org/drools/release/5.4.0.CR1/drools-planner-docs/html_s...
Then upgrade to knowledge-api, drools-core and drools-compiler 5.4.0.CR1.
It's best to upgrade planner too, but you 'll need to follow this:
https://github.com/droolsjbpm/drools-planner/blob/master/drools-planner-d...
Thanks
Vikram
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With kind regards,
Geoffrey De Smet
12:45 a.m.
> 1. While looking at the solution created at the end of the local
search
> phase AND comparing to the moves output in the log file. I see that there
> are several instances where the log file shows a move BUT the output
> solution has the entity still on the previous planning variable.
> This is happening only towards the end of the phase (about last 8 steps)
> of
> the time terminated phase.
This sounds like a genuine bug.
Could you copy paste some logging output to show the issue more clearly?
Can you check if 5.4.0.CR1 still has the issue and create a jira:
https://issues.jboss.org/browse/JBRULES
I have upgraded to 5.4.0CR1 (both planner
and drools) and tried both the
generic change move and my custom implementation.
I still have instances where the log (DEBUG) shows tasks moved to new
resources, but the final (best) solution shows the task still on a previous
resource.
Before I create a JIRA for this, I want to show you a sample log output
describing the issue -
To read the planning entity string below: [<entity id> <resource string>
<task string> <start time> <end time>]
where <resource string>:
[<resource id> <resource name>]
and <task string>:
[<task id> <task name>]
2012-04-20 08:28:05,411 [main] DEBUG DefaultGreedyFitSolverPhase - Step
index (816), time spend (36875), score (-110hard/32200soft), initialized
planning entity ([817 [49 W502] [19664 TASK817] 19Mar12.03:00 19Mar12.05:00
]).
...
2012-04-20 08:28:12,005 [main] INFO DefaultGreedyFitSolverPhase - Phase
constructionHeuristic ended: step total (974), time spend (43469), best
score (-183hard/38700soft)
2012-04-20 08:28:12,536 [main] DEBUG DefaultLocalSearchSolverPhase -
Step index (0), time spend (44000), score (-183hard/38700soft), best
score (-183hard/38700soft), accepted move size (800) for picked step ([817
[49 W502] [19664 TASK817] 19Mar12.03:00 19Mar12.05:00 ] => [102 W140]).
...
2012-04-20 08:30:01,974 [main] DEBUG DefaultLocalSearchSolverPhase -
Step index (566), time spend (153438), score (-175hard/39900soft), best
score (-175hard/39900soft), accepted move size (800) for picked step ([817
[102 W140] [19664 TASK817] 19Mar12.03:00 19Mar12.05:00 ] => [94 W132])
...
2012-04-20 08:30:15,880 [main] DEBUG DefaultLocalSearchSolverPhase -
Step index (637), time spend (167344), score (-175hard/39900soft), best
score (-175hard/39900soft), accepted move size (800) for picked step ([817
[94 W132] [19664 TASK817] 19Mar12.03:00 19Mar12.05:00 ] => [481 608]).
...
You can see that task817 was assigned to resource W502 by the construction
heuristic. Local search (Tabu) then moved this to resource W140, next to
W132 and finally to 608.
When I read the best solution obtained at the end of the local search (time
terminated), then TASK817 is showing as assigned to W140.
What is strange is that the log file shows a successful move W140-->W132 and
ALSO W132-->608. Why did W132-->608 succeed if the task was still left on
W140?
> However the final output
> shows the constraint still EXISTS between the two entities (even though
> the
> overlap is no longer present). As a result even though the constraints
> are
> actually removed, the score is NOT going down as the planner constraints
> still exist.
> The rule used by me is as follows (Allocation is the planning entity and
> ...
Smells like a memory corruption in drools-core. There is one fixed for
5.4.0.CR1, so
First turn on <environmentMode>TRACE</...> and see what it outputs.
Then upgrade to knowledge-api, drools-core and drools-compiler 5.4.0.CR1.
On
upgrading to 5.4.0CR1, I am facing a new issue in determining which
constraints are broken and hence unable to verify if my original issue is
fixed.
I am using the Drools Score Director and use the GUI hack to determine the
list of constraints met during solving. However the iterator returned is
empty even though I know that a lot of rules are met -
(Iterator<ConstraintOccurrence>) workingMemory.iterateObjects(new
ClassObjectFilter(ConstraintOccurrence.class));
Note that the workingMemory instance is not null, just the iterator returned
has no entries.
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9:10 a.m.
Op 20-04-12 07:45, duggal schreef:
>> 1. While looking at the solution created at the end of the
local search
>> phase AND comparing to the moves output in the log file. I see that there
>> are several instances where the log file shows a move BUT the output
>> solution has the entity still on the previous planning variable.
>> This is happening only towards the end of the phase (about last 8 steps)
>> of
>> the time terminated phase.
> This sounds like a genuine bug.
> Could you copy paste some logging output to show the issue more clearly?
> Can you check if 5.4.0.CR1 still has the issue and create a jira:
> https://issues.jboss.org/browse/JBRULES
I have upgraded to 5.4.0CR1 (both planner and drools) and tried both the
generic change move and my custom implementation.
I still have instances where the log (DEBUG) shows tasks moved to new
resources, but the final (best) solution shows the task still on a previous
resource.
Before I create a JIRA for this, I want to show you a sample log output
describing the issue -
To read the planning entity string below: [<entity id> <resource string>
<task string> <start time> <end time>]
where<resource string>:
[<resource id> <resource name>]
and<task string>:
[<task id> <task name>]
2012-04-20 08:28:05,411 [main] DEBUG DefaultGreedyFitSolverPhase - Step
index (816), time spend (36875), score (-110hard/32200soft), initialized
planning entity ([817 [49 W502] [19664 TASK817] 19Mar12.03:00 19Mar12.05:00
]).
...
2012-04-20 08:28:12,005 [main] INFO DefaultGreedyFitSolverPhase - Phase
constructionHeuristic ended: step total (974), time spend (43469), best
score (-183hard/38700soft)
2012-04-20 08:28:12,536 [main] DEBUG DefaultLocalSearchSolverPhase -
Step index (0), time spend (44000), score (-183hard/38700soft), best
score (-183hard/38700soft), accepted move size (800) for picked step ([817
[49 W502] [19664 TASK817] 19Mar12.03:00 19Mar12.05:00 ] => [102 W140]).
...
2012-04-20 08:30:01,974 [main] DEBUG DefaultLocalSearchSolverPhase -
Step index (566), time spend (153438), score (-175hard/39900soft), best
score (-175hard/39900soft), accepted move size (800) for picked step ([817
[102 W140] [19664 TASK817] 19Mar12.03:00 19Mar12.05:00 ] => [94 W132])
...
2012-04-20 08:30:15,880 [main] DEBUG DefaultLocalSearchSolverPhase -
Step index (637), time spend (167344), score (-175hard/39900soft), best
score (-175hard/39900soft), accepted move size (800) for picked step ([817
[94 W132] [19664 TASK817] 19Mar12.03:00 19Mar12.05:00 ] => [481 608]).
...
You can see that task817 was assigned to resource W502 by the construction
heuristic. Local search (Tabu) then moved this to resource W140, next to
W132 and finally to 608.
When I read the best solution obtained at the end of the local search (time
terminated), then TASK817 is showing as assigned to W140.
What is strange is that the log file shows a successful move W140-->W132 and
ALSO W132-->608. Why did W132-->608 succeed if the task was still left on
W140?
See your jira: https://issues.jboss.org/browse/JBRULES-3471
"The last solution is not necessarily the best solution.
Planner reminders the best solution it encounters, but when it hits a
local optima, it will need to do a few steps that have worse solution to
get out of it and find a better local optima.
The log clearly says ", best score", not ", new best score", so
that's
normal that that step move isn't in the best solution (unless later a
new best solution is found and no other step move has undone that step
move)."
>> However the final output
>> shows the constraint still EXISTS between the two entities (even though
>> the
>> overlap is no longer present). As a result even though the constraints
>> are
>> actually removed, the score is NOT going down as the planner constraints
>> still exist.
>> The rule used by me is as follows (Allocation is the planning entity and
>> ...
> Smells like a memory corruption in drools-core. There is one fixed for
> 5.4.0.CR1, so
> First turn on<environmentMode>TRACE</...> and see what it outputs.
> Then upgrade to knowledge-api, drools-core and drools-compiler 5.4.0.CR1.
On upgrading to 5.4.0CR1, I am facing a new issue in determining which
constraints are broken and hence unable to verify if my original issue is
fixed.
It's probably because of this change:
[MAJOR] An uninitialized planning entity should be allowed to be put
into the working memory
without causing a NullPointerException because a planning variable is
still null.
Before in *.java:
@PlanningEntity(...)
public class Lecture ... {
@PlanningVariable(...)
public Period getPeriod() {
return period;
}
...
public Day getDay() {
return period.getDay();
}
public int getTimeslotIndex() {
return period.getTimeslot().getTimeslotIndex();
}
...
}
After in *.java:
@PlanningEntity(...)
public class Lecture ... {
@PlanningVariable(...)
public Period getPeriod() {
return period;
}
...
public Day getDay() {
if (period == null) {
return null;
}
return period.getDay();
}
public int getTimeslotIndex() {
if (period == null) {
return Integer.MIN_VALUE;
}
return period.getTimeslot().getTimeslotIndex();
}
...
}
I am using the Drools Score Director and use the GUI hack to
determine the
list of constraints met during solving. However the iterator returned is
empty even though I know that a lot of rules are met -
(Iterator<ConstraintOccurrence>) workingMemory.iterateObjects(new
ClassObjectFilter(ConstraintOccurrence.class));
Note that the workingMemory instance is not null, just the iterator returned
has no entries.
Call scoreDirector.calcluateScore() first.
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With kind regards,
Geoffrey De Smet
4601
days inactive
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duggal -
Geoffrey De Smet