You are viewing a plain text version of this content. The canonical link for it is here.

Posted to users@jena.apache.org by "Martin, David" <Da...@nuance.com> on 2016/04/28 00:27:01 UTC

Rules engine numeric built-ins not succeeding

Rules engine built-ins that take numeric arguments, such as sum and greaterThan, are not working for me.  My situation is as follows:

I'm loading a simple NT file into a default model:
       Model contextData = FileManager.get().loadModel(contextPath, "N3");

The NT file includes the following triple:
      <item1> <hasHeight> "8"^^<http://www.w3.org/2001/XMLSchema/integer> .

I'm creating an inference model in the usual way:

    List rules = Rule.rulesFromURL("file:C:/test.rule");
   Reasoner reasoner = new GenericRuleReasoner(rules);
   Infmodel inf = ModelFactory.createInfModel(reasoner, contextData);

I have the following rule:

[checkItemHeight:
    (?item, hasHeight, ?height),
    print('In checkItemHeight antecedent:', ?height),
    greaterThan(?height, "7"^^http://www.w3.org/2001/XMLSchema/integer),
   ->
    print('In checkItemHeight:', ?height)
]

The first print clause succeeds:
    'In checkCarHeight antecedent:' '8'^^http://www.w3.org/2001/XMLSchema/integer

 but the call to greaterThan never succeeds; the rule never fires. I've tried different data types in the NT file and in the rules file, but nothing works. The *only* thing I can get to work is when I use two simple constants, with no datatype, in the rules file:
     greaterThan(8, 7),

I've looked around for discussions and documentation related to this, and I've looked at the Jena source code for greaterThan, but to no avail. I'd greatly appreciate some clarification of what's going on here, and what approaches*will* work.

Thanks!
David Martin
AI Lab
Nuance Communications

Re: Rules engine numeric built-ins not succeeding

Posted by "Martin, David" <Da...@nuance.com>.

Thanks for taking a look, and finding the problem, Dave!

I don't know how I missed that. Seems like a case of not seeing the trees because of the forest.

--- David
--- with personal assistance by Siri

> On Apr 28, 2016, at 3:48 AM, Dave Reynolds <da...@gmail.com> wrote:
> 
> Hi David,
> 
>> On 27/04/16 23:27, Martin, David wrote:
>> Rules engine built-ins that take numeric arguments, such as sum and greaterThan, are not working for me.  My situation is as follows:
>> 
>> I'm loading a simple NT file into a default model:
>>        Model contextData = FileManager.get().loadModel(contextPath, "N3");
>> 
>> The NT file includes the following triple:
>>       <item1> <hasHeight> "8"^^<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.w3.org_2001_XMLSchema_integer&d=CwIC-g&c=djjh8EKwHtOepW4Bjau0lKhLlu-DxM1dlgP0rrLsOzY&r=RvcUHmbqwXWRvprio0Md4_6qsPsb-hvwu22_Hd-fP_I&m=zY12eZypqbHFzLmEd-BtXmn7Ldz-wbMhYMkKRbuEyLY&s=A0ZCnA3lEfZmMJuRbxFZB3kjMYUuEfiwPSalXzjWLNw&e= > .
>> 
>> I'm creating an inference model in the usual way:
>> 
>>     List rules = Rule.rulesFromURL("file:C:/test.rule");
>>    Reasoner reasoner = new GenericRuleReasoner(rules);
>>    Infmodel inf = ModelFactory.createInfModel(reasoner, contextData);
>> 
>> I have the following rule:
>> 
>> [checkItemHeight:
>>     (?item, hasHeight, ?height),
>>     print('In checkItemHeight antecedent:', ?height),
>>     greaterThan(?height, "7"^^https://urldefense.proofpoint.com/v2/url?u=http-3A__www.w3.org_2001_XMLSchema_integer&d=CwIC-g&c=djjh8EKwHtOepW4Bjau0lKhLlu-DxM1dlgP0rrLsOzY&r=RvcUHmbqwXWRvprio0Md4_6qsPsb-hvwu22_Hd-fP_I&m=zY12eZypqbHFzLmEd-BtXmn7Ldz-wbMhYMkKRbuEyLY&s=A0ZCnA3lEfZmMJuRbxFZB3kjMYUuEfiwPSalXzjWLNw&e= ),
>>    ->
>>     print('In checkItemHeight:', ?height)
>> ]
>> 
>> The first print clause succeeds:
>>     'In checkCarHeight antecedent:' '8'^^https://urldefense.proofpoint.com/v2/url?u=http-3A__www.w3.org_2001_XMLSchema_integer&d=CwIC-g&c=djjh8EKwHtOepW4Bjau0lKhLlu-DxM1dlgP0rrLsOzY&r=RvcUHmbqwXWRvprio0Md4_6qsPsb-hvwu22_Hd-fP_I&m=zY12eZypqbHFzLmEd-BtXmn7Ldz-wbMhYMkKRbuEyLY&s=A0ZCnA3lEfZmMJuRbxFZB3kjMYUuEfiwPSalXzjWLNw&e= 
>>  but the call to greaterThan never succeeds; the rule never fires. I've tried different data types in the NT file and in the rules file, but nothing works. The *only* thing I can get to work is when I use two simple constants, with no datatype, in the rules file:
>>      greaterThan(8, 7),
>> 
>> I've looked around for discussions and documentation related to this, and I've looked at the Jena source code for greaterThan, but to no avail. I'd greatly appreciate some clarification of what's going on here, and what approaches*will* work.
> 
> My first thought was "that certainly should have worked" and it took a while to spot the deliberate mistake ...
> 
> The RDF namespace for XSD is
>   https://urldefense.proofpoint.com/v2/url?u=http-3A__www.w3.org_2001_XMLSchema-23&d=CwIC-g&c=djjh8EKwHtOepW4Bjau0lKhLlu-DxM1dlgP0rrLsOzY&r=RvcUHmbqwXWRvprio0Md4_6qsPsb-hvwu22_Hd-fP_I&m=zY12eZypqbHFzLmEd-BtXmn7Ldz-wbMhYMkKRbuEyLY&s=ZQUIuUP_BGNgQbkmNXGI159IIiDpS7vavTw_SiHLhZs&e= not
>   https://urldefense.proofpoint.com/v2/url?u=http-3A__www.w3.org_2001_XMLSchema_&d=CwIC-g&c=djjh8EKwHtOepW4Bjau0lKhLlu-DxM1dlgP0rrLsOzY&r=RvcUHmbqwXWRvprio0Md4_6qsPsb-hvwu22_Hd-fP_I&m=zY12eZypqbHFzLmEd-BtXmn7Ldz-wbMhYMkKRbuEyLY&s=Ka1WP37ZOigM8tbnkH3GowMMlIeWEZ-HZzdHSK7VPYk&e= 
> So what's happening is that both the NT parse and the rules parse are creating typed literals but those literals don't have number semantics because the URI is wrong. The greaterThan builtin returns false for incomparable cases.
> 
> If you change your data to be:
> 
>  <item1> <hasHeight> "8"^^<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.w3.org_2001_XMLSchema-23integer&d=CwIC-g&c=djjh8EKwHtOepW4Bjau0lKhLlu-DxM1dlgP0rrLsOzY&r=RvcUHmbqwXWRvprio0Md4_6qsPsb-hvwu22_Hd-fP_I&m=zY12eZypqbHFzLmEd-BtXmn7Ldz-wbMhYMkKRbuEyLY&s=N43qbXYFgT-W-lRM2Kol6hTbIpCA7zGsVQQbwegvgJA&e= > .
> 
> Then the rule:
> 
> [checkItemHeight:
>    (?item, data:hasHeight, ?height),
>    print('In checkItemHeight antecedent:', ?height),
>    greaterThan(?height, "7"^^https://urldefense.proofpoint.com/v2/url?u=http-3A__www.w3.org_2001_XMLSchema-23integer&d=CwIC-g&c=djjh8EKwHtOepW4Bjau0lKhLlu-DxM1dlgP0rrLsOzY&r=RvcUHmbqwXWRvprio0Md4_6qsPsb-hvwu22_Hd-fP_I&m=zY12eZypqbHFzLmEd-BtXmn7Ldz-wbMhYMkKRbuEyLY&s=N43qbXYFgT-W-lRM2Kol6hTbIpCA7zGsVQQbwegvgJA&e= )
>   ->
>    print('In checkItemHeight:', ?height)
> ]
> 
> works, as does
> 
> [checkItemHeight:
>    (?item, data:hasHeight, ?height),
>    print('In checkItemHeight antecedent:', ?height),
>    greaterThan(?height, 7)
>   ->
>    print('In checkItemHeight:', ?height)
> ]
> 
> Dave

Re: Rules engine numeric built-ins not succeeding

Posted by Dave Reynolds <da...@gmail.com>.

Hi David,

On 27/04/16 23:27, Martin, David wrote:
> Rules engine built-ins that take numeric arguments, such as sum and greaterThan, are not working for me.  My situation is as follows:
>
> I'm loading a simple NT file into a default model:
>         Model contextData = FileManager.get().loadModel(contextPath, "N3");
>
> The NT file includes the following triple:
>        <item1> <hasHeight> "8"^^<http://www.w3.org/2001/XMLSchema/integer> .
>
> I'm creating an inference model in the usual way:
>
>      List rules = Rule.rulesFromURL("file:C:/test.rule");
>     Reasoner reasoner = new GenericRuleReasoner(rules);
>     Infmodel inf = ModelFactory.createInfModel(reasoner, contextData);
>
> I have the following rule:
>
> [checkItemHeight:
>      (?item, hasHeight, ?height),
>      print('In checkItemHeight antecedent:', ?height),
>      greaterThan(?height, "7"^^http://www.w3.org/2001/XMLSchema/integer),
>     ->
>      print('In checkItemHeight:', ?height)
> ]
>
> The first print clause succeeds:
>      'In checkCarHeight antecedent:' '8'^^http://www.w3.org/2001/XMLSchema/integer
>
>   but the call to greaterThan never succeeds; the rule never fires. I've tried different data types in the NT file and in the rules file, but nothing works. The *only* thing I can get to work is when I use two simple constants, with no datatype, in the rules file:
>       greaterThan(8, 7),
>
> I've looked around for discussions and documentation related to this, and I've looked at the Jena source code for greaterThan, but to no avail. I'd greatly appreciate some clarification of what's going on here, and what approaches*will* work.

My first thought was "that certainly should have worked" and it took a 
while to spot the deliberate mistake ...

The RDF namespace for XSD is
    http://www.w3.org/2001/XMLSchema#
not
    http://www.w3.org/2001/XMLSchema/

So what's happening is that both the NT parse and the rules parse are 
creating typed literals but those literals don't have number semantics 
because the URI is wrong. The greaterThan builtin returns false for 
incomparable cases.

If you change your data to be:

   <item1> <hasHeight> "8"^^<http://www.w3.org/2001/XMLSchema#integer> .

Then the rule:

[checkItemHeight:
     (?item, data:hasHeight, ?height),
     print('In checkItemHeight antecedent:', ?height),
     greaterThan(?height, "7"^^http://www.w3.org/2001/XMLSchema#integer)
    ->
     print('In checkItemHeight:', ?height)
]

works, as does

[checkItemHeight:
     (?item, data:hasHeight, ?height),
     print('In checkItemHeight antecedent:', ?height),
     greaterThan(?height, 7)
    ->
     print('In checkItemHeight:', ?height)
]

Dave