Hi,
Does Kuppitz’ NumberHelper come into play here?
https://github.com/apache/tinkerpop/blob/master/gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/util/NumberHelper.java
<https://github.com/apache/tinkerpop/blob/master/gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/util/NumberHelper.java>
Marko.
http://markorodriguez.com
> On Jul 25, 2017, at 6:08 AM, Robert Dale <[email protected]> wrote:
>
> I think gremlin should handle this case. It's a matter of setting the
> MathContext precision. I was trying to reproduce this in the shell but
> couldn't. Here's why and what groovy does:
>
> public Number divideImpl(Number left, Number right) {
> BigDecimal bigLeft = toBigDecimal(left);
> BigDecimal bigRight = toBigDecimal(right);
> try {
> return bigLeft.divide(bigRight);
> } catch (ArithmeticException e) {
> // set a DEFAULT precision if otherwise non-terminating
> int precision = Math.max(bigLeft.precision(),
> bigRight.precision()) + DIVISION_EXTRA_PRECISION;
> BigDecimal result = bigLeft.divide(bigRight, new
> MathContext(precision));
> int scale = Math.max(Math.max(bigLeft.scale(),
> bigRight.scale()), DIVISION_MIN_SCALE);
> if (result.scale() > scale) result = result.setScale(scale,
> BigDecimal.ROUND_HALF_UP);
> return result;
> }
> }
>
>
> Robert Dale
>
> On Tue, Jul 25, 2017 at 7:48 AM, Stephen Mallette <[email protected]>
> wrote:
>
>> Dan "The Stroke" LaRocque gave me some gory details on groovy's handling of
>> decimals/numbers which can make sack() do this:
>>
>> gremlin> g.withSack(2).V().sack(div).by(constant(3.0)).sack()
>> Non-terminating decimal expansion; no exact representable decimal result.
>> Type ':help' or ':h' for help.
>> Display stack trace? [yN]y
>> java.lang.ArithmeticException: Non-terminating decimal expansion; no exact
>> representable decimal result.
>> at java.math.BigDecimal.divide(BigDecimal.java:1690)
>> at
>> org.apache.tinkerpop.gremlin.process.traversal.
>> NumberHelper.lambda$static$45(NumberHelper.java:132)
>> at
>> org.apache.tinkerpop.gremlin.process.traversal.
>> NumberHelper.div(NumberHelper.java:219)
>> at
>> org.apache.tinkerpop.gremlin.process.traversal.
>> NumberHelper.div(NumberHelper.java:214)
>> at
>> org.apache.tinkerpop.gremlin.process.traversal.Operator$4.
>> apply(Operator.java:47)
>> at
>> org.apache.tinkerpop.gremlin.process.traversal.step.
>> sideEffect.SackValueStep.sideEffect(SackValueStep.java:60)
>> at
>> org.apache.tinkerpop.gremlin.process.traversal.step.
>> sideEffect.SideEffectStep.processNextStart(SideEffectStep.java:39)
>> at
>> org.apache.tinkerpop.gremlin.process.traversal.step.util.
>> AbstractStep.hasNext(AbstractStep.java:143)
>> at
>> org.apache.tinkerpop.gremlin.process.traversal.step.util.
>> ExpandableStepIterator.next(ExpandableStepIterator.java:50)
>> at
>> org.apache.tinkerpop.gremlin.process.traversal.step.map.
>> MapStep.processNextStart(MapStep.java:36)
>> at
>> org.apache.tinkerpop.gremlin.process.traversal.step.util.
>> AbstractStep.hasNext(AbstractStep.java:143)
>> at
>> org.apache.tinkerpop.gremlin.process.traversal.util.
>> DefaultTraversal.hasNext(DefaultTraversal.java:184)
>> at
>> org.apache.tinkerpop.gremlin.console.Console$_closure3.
>> doCall(Console.groovy:237)
>> at sun.reflect.GeneratedMethodAccessor39.invoke(Unknown Source)
>> ...
>> at
>> org.codehaus.groovy.runtime.ScriptBytecodeAdapter.invokeMethodOnSuperN(
>> ScriptBytecodeAdapter.java:132)
>> at
>> org.codehaus.groovy.runtime.ScriptBytecodeAdapter.invokeMethodOnSuper0(
>> ScriptBytecodeAdapter.java:152)
>> at
>> org.codehaus.groovy.tools.shell.InteractiveShellRunner.
>> run(InteractiveShellRunner.groovy:83)
>> at
>> org.codehaus.groovy.vmplugin.v7.IndyInterface.selectMethod(
>> IndyInterface.java:232)
>> at org.apache.tinkerpop.gremlin.console.Console.<init>(Console.groovy:169)
>> at
>> org.codehaus.groovy.vmplugin.v7.IndyInterface.selectMethod(
>> IndyInterface.java:232)
>> at org.apache.tinkerpop.gremlin.console.Console.main(Console.groovy:478)
>>
>> this does work well if the Gremlin has more explicit typing:
>>
>> gremlin> g.withSack(2).V().sack(div).by(constant(3.0d)).sack()
>> ==>0.6666666666666666
>> ==>0.6666666666666666
>> ==>0.6666666666666666
>> ==>0.6666666666666666
>> ==>0.6666666666666666
>> ==>0.6666666666666666
>> gremlin> g.withSack(2d).V().sack(div).by(constant(3)).sack()
>> ==>0.6666666666666666
>> ==>0.6666666666666666
>> ==>0.6666666666666666
>> ==>0.6666666666666666
>> ==>0.6666666666666666
>> ==>0.6666666666666666
>> gremlin> g.withSack(2).V().sack(div).by(constant(3)).sack()
>> ==>0
>> ==>0
>> ==>0
>> ==>0
>> ==>0
>> ==>0
>>
>> Is this something we can make nicer? Create a ticket?
>>
