[rules-users] Drools 5.5 divide by 0 exception

[Wolfgang Laun]

I can anticipate the answer where OP says that there is a constraint
restricting argVolume to > 0. However, I don't think that independent
constraints such as we see them in this rule are evaluated as if they
were in a single logical expression, with Java semantics.

The seductive possibility of binding to a half-baked expression (i.e.,
$ratio:(volumeAccumulations["total"]/consolidatdVolume.avgVolume))
should be discarded. This value can safely be computed on the RHS
where the denominator's  value being !=0 is asserted.

-W

On 01/11/2013, Stephen Masters <stephen.masters at me.com> wrote:
> Divide by zero exceptions usually occur when you try to divide by zero.
>
> So … first question … is consolidatdVolume.avgVolume ever zero?
>
>
> On 1 Nov 2013, at 16:17, gboro54 <gboro54 at gmail.com> wrote:
>
>> I have rules like the following:
>>
>> rule "Add Baseline to Context if it does not exists exists or not greater
>> then 0"
>> 	no-loop true
>> 	when
>> 		$context:Context($id:id,baselineParticipation==null ||
>> 				
>> baselineParticipation.baselineRatio==null||baselineParticipation.baselineRatio==0)
>> 	then
>> 		modify($firm) {setBaselineParticipation(new
>> BaselineParticipation($id,new
>> BigDecimal(0.00485)))};
>> 		
>> end
>>
>> rule "Calculate Participation Ratio"
>> 	no-loop true
>> 	when
>> 		$context:Context(consolidatdVolume!=null,consolidatdVolume.avgVolume>0,
>> 				   volumeAccumulations["total"]!=null,volumeAccumulations["total"]>0,
>> 				   $ratio:(volumeAccumulations["total"]/consolidatdVolume.avgVolume))
>> 	then
>> 		ConcurrentMap calculatedRatios=$firm.getCalculatedRatios();
>> 		calculatedRatios.put("fparticipationRatio",new BigDecimal($ratio));
>> 		modify($firm){setCalculatedRatios(calculatedRatios)};
>> end
>>
>> Despite the checks I get the following exception and any insight into why
>> would be great:
>>
>> Exception executing consequence for rule "Calculate Firm Participation
>> Ratio" in com.nasdaq.rms.nq.status: java.lang.ArithmeticException: / by
>> zero
>> Exception executing consequence for rule "Calculate Firm Participation
>> Ratio" in com.nasdaq.rms.nq.status: java.lang.ArithmeticException: / by
>> zero
>> 	at
>> org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
>> 	at
>> org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1297)
>> 	at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:1221)
>> 	at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1456)
>> 	at
>> org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:710)
>> 	at
>> org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:674)
>> 	at
>> org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:230)
>> 	at
>> com.nasdaq.fq.rms.workflow.processor.rules.PerformanceStatusAssignmentProcessor.doWork(PerformanceStatusAssignmentProcessor.java:156)
>> 	at com.ften.ssr.workqueue.WorkItemRunnable.run(WorkItemRunnable.java:48)
>> 	at
>> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
>> 	at
>> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
>> 	at java.lang.Thread.run(Thread.java:724)
>> Caused by: java.lang.ArithmeticException: / by zero
>> 	at ConditionEvaluatorda6271cf5a744b6bbdb9c717cae2edb7.evaluate(Unknown
>> Source)
>> 	at
>> org.drools.rule.constraint.MvelConstraint.evaluate(MvelConstraint.java:200)
>> 	at
>> org.drools.rule.constraint.MvelConstraint.isAllowed(MvelConstraint.java:157)
>> 	at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:154)
>> 	at
>> org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:507)
>> 	at
>> org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:432)
>> 	at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157)
>> 	at
>> org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:507)
>> 	at
>> org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:432)
>> 	at
>> org.drools.reteoo.ObjectTypeNode.modifyObject(ObjectTypeNode.java:314)
>> 	at
>> org.drools.reteoo.EntryPointNode.modifyObject(EntryPointNode.java:265)
>> 	at org.drools.common.NamedEntryPoint.update(NamedEntryPoint.java:483)
>> 	at org.drools.common.NamedEntryPoint.update(NamedEntryPoint.java:383)
>> 	at
>> org.drools.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:337)
>> 	at
>> com.nasdaq.rms.nq.status.Rule_Calculate_Firm_Participation_Ratio_cfb033f33c2b404fb2bff8e1b9af0175.defaultConsequence(Unknown
>> Source)
>> 	at
>> com.nasdaq.rms.nq.status.Rule_Calculate_Firm_Participation_Ratio_cfb033f33c2b404fb2bff8e1b9af0175DefaultConsequenceInvokerGenerated.evaluate(Unknown
>> Source)
>> 	at
>> com.nasdaq.rms.nq.status.Rule_Calculate_Firm_Participation_Ratio_cfb033f33c2b404fb2bff8e1b9af0175DefaultConsequenceInvoker.evaluate(Unknown
>> Source)
>> 	at
>> org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1287)
>> 	... 10 more
>>
>>
>>
>> --
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