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1 | 1 | # cs-expert-system-shell
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2 |
| -C# implementation of an expert system shell |
| 2 | +C# implementation of an expert system shell, targeting .Net Core 1.1 |
3 | 3 |
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4 | 4 | [](https://travis-ci.org/chen0040/cs-expert-system-shell)
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| 5 | + |
| 6 | +# Install |
| 7 | + |
| 8 | +Run the following command to install: |
| 9 | + |
| 10 | +Install-Package cs-expert-system-shell |
| 11 | + |
| 12 | +# Usage |
| 13 | + |
| 14 | +The sample code below shows how to create a rule engine and initialize it with a set of rules: |
| 15 | + |
| 16 | +```cs |
| 17 | +using chen0040.ExpertSystem; |
| 18 | +public RuleInferenceEngine getInferenceEngine() |
| 19 | +{ |
| 20 | + RuleInferenceEngine rie = new RuleInferenceEngine(); |
| 21 | + |
| 22 | + Rule rule = new Rule("Bicycle"); |
| 23 | + rule.AddAntecedent(new IsClause("vehicleType", "cycle")); |
| 24 | + rule.AddAntecedent(new IsClause("num_wheels", "2")); |
| 25 | + rule.AddAntecedent(new IsClause("motor", "no")); |
| 26 | + rule.setConsequent(new IsClause("vehicle", "Bicycle")); |
| 27 | + rie.AddRule(rule); |
| 28 | + |
| 29 | + rule = new Rule("Tricycle"); |
| 30 | + rule.AddAntecedent(new IsClause("vehicleType", "cycle")); |
| 31 | + rule.AddAntecedent(new IsClause("num_wheels", "3")); |
| 32 | + rule.AddAntecedent(new IsClause("motor", "no")); |
| 33 | + rule.setConsequent(new IsClause("vehicle", "Tricycle")); |
| 34 | + rie.AddRule(rule); |
| 35 | + |
| 36 | + rule = new Rule("Motorcycle"); |
| 37 | + rule.AddAntecedent(new IsClause("vehicleType", "cycle")); |
| 38 | + rule.AddAntecedent(new IsClause("num_wheels", "2")); |
| 39 | + rule.AddAntecedent(new IsClause("motor", "yes")); |
| 40 | + rule.setConsequent(new IsClause("vehicle", "Motorcycle")); |
| 41 | + rie.AddRule(rule); |
| 42 | + |
| 43 | + rule = new Rule("SportsCar"); |
| 44 | + rule.AddAntecedent(new IsClause("vehicleType", "automobile")); |
| 45 | + rule.AddAntecedent(new IsClause("size", "medium")); |
| 46 | + rule.AddAntecedent(new IsClause("num_doors", "2")); |
| 47 | + rule.setConsequent(new IsClause("vehicle", "Sports_Car")); |
| 48 | + rie.AddRule(rule); |
| 49 | + |
| 50 | + rule = new Rule("Sedan"); |
| 51 | + rule.AddAntecedent(new IsClause("vehicleType", "automobile")); |
| 52 | + rule.AddAntecedent(new IsClause("size", "medium")); |
| 53 | + rule.AddAntecedent(new IsClause("num_doors", "4")); |
| 54 | + rule.setConsequent(new IsClause("vehicle", "Sedan")); |
| 55 | + rie.AddRule(rule); |
| 56 | + |
| 57 | + rule = new Rule("MiniVan"); |
| 58 | + rule.AddAntecedent(new IsClause("vehicleType", "automobile")); |
| 59 | + rule.AddAntecedent(new IsClause("size", "medium")); |
| 60 | + rule.AddAntecedent(new IsClause("num_doors", "3")); |
| 61 | + rule.setConsequent(new IsClause("vehicle", "MiniVan")); |
| 62 | + rie.AddRule(rule); |
| 63 | + |
| 64 | + rule = new Rule("SUV"); |
| 65 | + rule.AddAntecedent(new IsClause("vehicleType", "automobile")); |
| 66 | + rule.AddAntecedent(new IsClause("size", "large")); |
| 67 | + rule.AddAntecedent(new IsClause("num_doors", "4")); |
| 68 | + rule.setConsequent(new IsClause("vehicle", "SUV")); |
| 69 | + rie.AddRule(rule); |
| 70 | + |
| 71 | + rule = new Rule("Cycle"); |
| 72 | + rule.AddAntecedent(new LessClause("num_wheels", "4")); |
| 73 | + rule.setConsequent(new IsClause("vehicleType", "cycle")); |
| 74 | + rie.AddRule(rule); |
| 75 | + |
| 76 | + rule = new Rule("Automobile"); |
| 77 | + rule.AddAntecedent(new IsClause("num_wheels", "4")); |
| 78 | + rule.AddAntecedent(new IsClause("motor", "yes")); |
| 79 | + rule.setConsequent(new IsClause("vehicleType", "automobile")); |
| 80 | + rie.AddRule(rule); |
| 81 | + |
| 82 | + return rie; |
| 83 | +} |
| 84 | +``` |
| 85 | + |
| 86 | +The sample code below shows how to use forward chaining in the rule engine to derive more facts from the known facts using rules: |
| 87 | + |
| 88 | +```cs |
| 89 | +RuleInferenceEngine rie = getInferenceEngine(); |
| 90 | +rie.AddFact(new IsClause("num_wheels", "4")); |
| 91 | +rie.AddFact(new IsClause("motor", "yes")); |
| 92 | +rie.AddFact(new IsClause("num_doors", "3")); |
| 93 | +rie.AddFact(new IsClause("size", "medium")); |
| 94 | + |
| 95 | +console.WriteLine("before inference"); |
| 96 | +console.WriteLine("{0}", rie.Facts); |
| 97 | +console.WriteLine(""); |
| 98 | + |
| 99 | +rie.Infer(); //forward chain |
| 100 | +
|
| 101 | +console.WriteLine("after inference"); |
| 102 | +console.WriteLine("{0}", rie.Facts); |
| 103 | +console.WriteLine(""); |
| 104 | +``` |
| 105 | + |
| 106 | +The sample code below shows how to use the backward chaining to reach conclusion for a target variable given a set of known facts: |
| 107 | + |
| 108 | +```cs |
| 109 | +RuleInferenceEngine rie = getInferenceEngine(); |
| 110 | +rie.AddFact(new IsClause("num_wheels", "4")); |
| 111 | +rie.AddFact(new IsClause("motor", "yes")); |
| 112 | +rie.AddFact(new IsClause("num_doors", "3")); |
| 113 | +rie.AddFact(new IsClause("size", "medium")); |
| 114 | + |
| 115 | +console.WriteLine("Infer: vehicle"); |
| 116 | + |
| 117 | +List<Clause> unproved_conditions = new List<Clause>(); |
| 118 | + |
| 119 | +Clause conclusion = rie.Infer("vehicle", unproved_conditions); |
| 120 | + |
| 121 | +console.WriteLine("Conclusion: " + conclusion); |
| 122 | + |
| 123 | +Assert.Equal(conclusion.Value, "MiniVan"); |
| 124 | +``` |
| 125 | + |
| 126 | +The sample code below shows how to use the rule engine to ask more questions when it fails to reach conclusion for the target variable given a limited set of known facts: |
| 127 | + |
| 128 | +```cs |
| 129 | +RuleInferenceEngine rie = getInferenceEngine(); |
| 130 | + |
| 131 | +console.WriteLine("Infer with All Facts Cleared:"); |
| 132 | +rie.ClearFacts(); |
| 133 | + |
| 134 | +List<Clause> unproved_conditions = new List<Clause>(); |
| 135 | + |
| 136 | +Clause conclusion = null; |
| 137 | +while (conclusion == null) |
| 138 | +{ |
| 139 | + conclusion = rie.Infer("vehicle", unproved_conditions); |
| 140 | + if (conclusion == null) |
| 141 | + { |
| 142 | + if (unproved_conditions.Count == 0) |
| 143 | + { |
| 144 | + break; |
| 145 | + } |
| 146 | + Clause c = unproved_conditions[0]; |
| 147 | + console.WriteLine("ask: " + c + "?"); |
| 148 | + unproved_conditions.Clear(); |
| 149 | + console.WriteLine("What is " + c.Variable + "?"); |
| 150 | + String value = Console.ReadLine(); |
| 151 | + rie.AddFact(new IsClause(c.Variable, value)); |
| 152 | + } |
| 153 | +} |
| 154 | + |
| 155 | +console.WriteLine("Conclusion: " + conclusion); |
| 156 | +console.WriteLine("Memory: "); |
| 157 | +console.WriteLine("{0}", rie.Facts); |
| 158 | +``` |
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