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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">Why do you need to handcode a name unique to a particular activation of the rule? Isn’t the combination of (sentence, rulename) unique enough?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">What I’m a bit confused about is what you are trying to achieve, is the RHS the same for all rules (or at least all combinations that match the same sentence)?
If they are different then are you sure you don’t want them all to fire?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">If your rules share the same calculation logic then one approach you could look into is separating the selection logic from the calculation logic.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">Your existing rules would insert logically an object “CalculationRequired(sentence, calculationName)” with multiple rules inserting the same fact.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">Your calculations would be separate rules triggered by a LHS of the form s : sentence, exists(CalcuationRequired(calculationName = “SomeName”, sentence =
s)).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">Don’t know if that helps or not,<o:p></o:p></span></p>
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color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">Thomas<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:
"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;
font-family:"Tahoma","sans-serif""> rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org]
<b>On Behalf Of </b>Tracey Lall<br>
<b>Sent:</b> 24 March 2010 18:35<br>
<b>To:</b> Rules Users List<br>
<b>Subject:</b> Re: [rules-users] Mechanism to prevent redundant inferences<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks Thomas<o:p></o:p></p>
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<p class="MsoNormal"> In the rhs I am doing some calculations and then inserting Proven objects. The calculations are significant so I would prefer to prevent the rule fires from occurring. My inclusion of<o:p></o:p></p>
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<p class="MsoNormal"><span class="apple-style-span"><span style="font-size:11.5pt;
color:#1F497D">Piton(predicate == $sentence, rule=”uniquerulename”)</span></span><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span class="apple-style-span"><span style="font-size:11.5pt;
color:#1F497D">does work, but its quite a lot of work to handcode a name which is unique to the particular activation of the rule.</span></span><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">thanks for your help!<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">Tracey<o:p></o:p></p>
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<p class="MsoNormal">2010/3/22 Swindells, Thomas <<a href="mailto:TSwindells@nds.com">TSwindells@nds.com</a>><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;color:#1F497D">Presumably all your RHS do is insert your Proven objects. If this is the case then my first question is do you actually need to put
in an optimisation here? How much is the work of evaluating a few extra rule nodes compared to the work and memory that will be required to evaluate the shadow facts and prevent the rules from firing.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;color:#1F497D">If you do want to try suppress rules firing couldn’t you have the following LHS?</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;color:#1F497D">Piton(predicate == $sentence, rule=”uniquerulename”) or not Proven(predicate == $sentence)</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;color:#1F497D">What I would recommend is lots of reading up about performance, testing, trying different combinations and generating the rete graph
that drools produces to see whether you have added more or less complexity to the graph. Also make sure you order your conditions so that the ones which are most likely to stop processing are placed first.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;color:#1F497D">Thomas</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span lang="EN-US" style="font-size:10.0pt">From:</span></b><span lang="EN-US" style="font-size:10.0pt">
<a href="mailto:rules-users-bounces@lists.jboss.org" target="_blank">rules-users-bounces@lists.jboss.org</a> [mailto:<a href="mailto:rules-users-bounces@lists.jboss.org" target="_blank">rules-users-bounces@lists.jboss.org</a>]
<b>On Behalf Of </b>Tracey Lall<br>
<b>Sent:</b> 20 March 2010 20:55<br>
<b>To:</b> <a href="mailto:rules-users@lists.jboss.org" target="_blank">rules-users@lists.jboss.org</a><br>
<b>Subject:</b> [rules-users] Mechanism to prevent redundant inferences</span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p><span lang="EN-US" style="font-size:10.0pt">Hi folks</span><o:p></o:p></p>
<p><span lang="EN-US" style="font-size:10.0pt"> I am writing a logical inference engine in <span style="background:#FFFFCC">drools. Logical sentences (class Sentence) which are proven are indicated by the fact Proven( sentence = $sentence )</span></span><o:p></o:p></p>
<p><span lang="EN-US" style="font-size:10.0pt">All Proven(sentence) facts are asserted using the <span style="background:#FFFFCC">drools</span> logical mechanism (since logical backtracking is required).</span><o:p></o:p></p>
<p><span lang="EN-US" style="font-size:10.0pt">For efficiency purposes I want to be able to suppress firing any rules which assert proof of a logical sentence which has already been proven (there may be multiple inferences which prove the same sentence).</span><o:p></o:p></p>
<p><span lang="EN-US" style="font-size:10.0pt">If the non existence of a proof of a sentence (not exists Proven(sentence=$sentence) is included in the lhs conditions then that causes problems when the rule logically asserts Proven(sentence) since the insertion
invalidates the lhs conditions and hence the rule causes its own retraction (the inserted fact handle return is null).</span><o:p></o:p></p>
<p><span style="font-size:10.0pt">As a way around this I created a class Piton() to record whether a particular rule has fired. The lhs conditions then become:</span><o:p></o:p></p>
<p><span style="font-size:10.0pt">(Proven( predicate == $sentence ) or Piton( fireName == $descriptor ) )</span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:10.0pt">And then in the body of the rule the first thing it asserts is the fact:</span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:10.0pt"> </span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:10.0pt">Piton( fireName == $descriptor )</span><o:p></o:p></p>
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<p><span style="font-size:10.0pt">Where $descriptor is a string built from the rulename + the set of facts which matched the lhs (ie a descriptor which is unique to the rule fire)</span><o:p></o:p></p>
<p><span style="font-size:10.0pt">With this approach when a rule asserts Proven(sentence) because it has also asserted Piton( fireName == descriptor ) ) the lhs of the rule still matches the the rule fire is not retracted.</span><o:p></o:p></p>
<p><span style="font-size:10.0pt">This approach works, but it is rather tedious to implement since the descriptor must be defined in such as way to make it unique (or as far as possible unique) to the particular rule activation. Since the drools variable is
not accessible in the lhs of a rule (and hence the activation details are not accessible in the lhs), this means that the descriptor must be handcoded to consist of all matching facts for that lhs.</span><o:p></o:p></p>
<p><span style="font-size:10.0pt">Is this approach the only way to prevent multiple rule firings for the same proof, or is there a simpler way to achieve this?</span><o:p></o:p></p>
<p><span style="font-size:10.0pt">Any advice greatly appreciated!</span><o:p></o:p></p>
<p><span style="font-size:10.0pt">thanks</span><o:p></o:p></p>
<p><span style="font-size:10.0pt">Tracey</span><o:p></o:p></p>
<p><span style="font-size:10.0pt"> </span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:10.0pt"> </span><o:p></o:p></p>
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