Drools Planner for purchasing optimization - good fit for problem?
by Schneider, Bill
I'm trying to understand whether Drools Planner is a good fit for a purchasing optimization problem.
The problem is something like this: there are X different items, each of which can be purchased from Y different vendors at different prices. The objective variable/function to minimize is the total amount purchased (sum(qty_i * price_i)).
Some vendor prices are conditional - only valid if you purchase more than some minimum threshold, or if you purchase more than some total quantity from that vendor. There are some additional constraints like dual-sourcing
- for some item x_i, exactly two vendors must be selected.
I feel like you *could* probably solve this problem in Drools Planner, but I'm not sure if it's the best way, or if a more traditional solver approach would be better. It feels more like a linear programming problem at its core, and I'm having a hard time figuring out where the boundary is - what kind of constraint would make the problem "non-convex" or "non-smooth" to the point where a local search (tabu, evolutionary etc.) is required?
Thanks for any help you can give.
--Bill
13 years, 10 months
2 problems with the keyword contains in HashMaps
by raffi
Hy.
I have problems, filtering data with the help of /contains/. I have a
HashMap with /long/-values as keys. In my rules I filter data in the
following way:
FilterCriteria(categories_slot1 contains $cid)
HashMap categories_slot1 is initialized with HashMap<Long, Double>. $cid is
set as long value in the corresponding class, too. Does this work in
general?
Second problem is that there is another HashMap with Strings as key values.
FilterCriteria(brands contains $brand)
The problem is, that /brands/-key value strings are not identical to $brand.
But $brand can contain the key value string. But contains only checks if
they are identical right?
Thanks
--
View this message in context: http://drools.46999.n3.nabble.com/2-problems-with-the-keyword-contains-in...
Sent from the Drools: User forum mailing list archive at Nabble.com.
13 years, 10 months
Unable to find implementation for BusinessRuleProvider
by John Peterson
Hi,
I've been experimenting with the Guided Rule Editor plug-in in Eclipse.
I've built a Drools Project using the default Hello World sample
application. I've created a new "Guided Rule" in my project called
"GuidedRule.brl" and get the associated "drools.package" with it. The
rule is simple:
WHEN
THEN
System.out.println("Rule has fired");
I build the knowledge base as follows:
private static KnowledgeBase readKnowledgeBase() throws
Exception {
KnowledgeBuilder kbuilder =
KnowledgeBuilderFactory.newKnowledgeBuilder();
kbuilder.add(ResourceFactory.newClassPathResource("SampleGuided.drl"),
ResourceType.BRL);
KnowledgeBuilderErrors errors = kbuilder.getErrors();
if (errors.size() > 0) {
for (KnowledgeBuilderError error: errors) {
System.err.println(error);
}
throw new IllegalArgumentException("Could not
parse knowledge.");
}
KnowledgeBase kbase =
KnowledgeBaseFactory.newKnowledgeBase();
kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());
return kbase;
}
The only line changed is adding the resource of type BRL.
When I try to run, I get the following error:
java.lang.RuntimeException: org.drools.compiler.DroolsParserException:
org.drools.CheckedDroolsException: Unable to find implementation for
BusinessRuleProvider
at
org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.j
ava:544)
at
org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.ja
va:28)
at com.sample.DroolsTest.readKnowledgeBase(DroolsTest.java:41)
at com.sample.DroolsTest.main(DroolsTest.java:23)
Caused by: org.drools.compiler.DroolsParserException:
org.drools.CheckedDroolsException: Unable to find implementation for
BusinessRuleProvider
at
org.drools.compiler.PackageBuilder.addPackageFromBrl(PackageBuilder.java
:386)
at
org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.j
ava:470)
... 3 more
Caused by: org.drools.CheckedDroolsException: Unable to find
implementation for BusinessRuleProvider
at
org.drools.compiler.BusinessRuleProviderFactory.throwNoImplementationFou
nd(BusinessRuleProviderFactory.java:66)
at
org.drools.compiler.BusinessRuleProviderFactory.loadProvider(BusinessRul
eProviderFactory.java:42)
at
org.drools.compiler.BusinessRuleProviderFactory.getProvider(BusinessRule
ProviderFactory.java:25)
at
org.drools.compiler.PackageBuilder.addPackageFromBrl(PackageBuilder.java
:366)
... 4 more
I've tried variations to add the drools.package as a PKG type, I've had
the rules (and package) in both "com.sample" and /src/main/rules, but I
can't seem to resolve the problem. "drools.package" has been updated to
include the package name (package com.sample;) and I import the message
class as well (even though it isn't being used currently).
I suspect the issue is simple, but I haven't been able to figure it out.
Any help would be appreciated.
13 years, 10 months
Protobuf Marshaller Question (ScheduledActivation Persistence)
by Philipp Herzig
Dear developers,
I believe this is a question for Edson.
I wonder if ScheduledActivations are added to the Agenda when
unmarshalling an existing session and fired as well, e.g., non-expired
timers.
I guess that this worked with the DefaultMarshaller implementation (at
least I can see LOCs in the InputMarshaller where normal or scheduled
activations are added to the newly created agenda). I cannot find
similar code in the ProtobufMarshaller or, more precisely, the
ProtobufInputMarshaller.
I also tried to override MarshallerProvider in order to use the
DefaultMarshaller but that is obviously not-consistent
(ClassCastException) with the current codebase anymore.
Hopefully, I am doing/understanding sth. completely wrong here.
Thanks for any help regarding this issue,
Philipp
13 years, 10 months
Query regarding guvnor and drools remote execution using categories of guvnor
by Krishnendra Nandi
Hi All
I am a newbie
I have a question
In guvnor we have categories
Using REST API we can access assets through categories like
/rest/categories/{}/assets ...something like this
I have a JSON object which gets populated which has references to binary
for all the assets
1) How do we construct the KnowledgeBase out of it and execute rules based
on those subset of rules ? is it advisable to do that ?
2) How do we get all the declarative facts residing inside guvnor remotely
from a Java client ?
--
Thanks and Regards
Krishnendra Nandi
Phone :+91-93727-08782
Skype :krish_nandi_78
Gtalk :krishnendra@gmail.com
13 years, 10 months
Finding the definition of a rule
by LStampf
Hi,
I am currently using a KnowledgeAgent to implement hot deployment in our
applications. So far this is working, but now the requirement arose to
remove specific rules via program call. I thought the easiest way would be
to remove the rule from the resources and let the KnowledgeAgent handle the
rest. But as far as I see, there is no way to get the source resource of a
rule from the KnowledgeBase/RuleBase. I guess I wont have another choice
than to parse the initial changeset, gather all resources, and go through
them to find and remove the rule.
But this seems like overkill to achieve something that simple. Does anybody
know a better way to remove specific rules while using a KnowledgeAgent.
kind regards
Lukas
--
View this message in context: http://drools.46999.n3.nabble.com/Finding-the-definition-of-a-rule-tp4020...
Sent from the Drools: User forum mailing list archive at Nabble.com.
13 years, 10 months
