cs-expert-system-shell
C# implementation of an expert system shell, targeting .Net Core 1.1
Install
Run the following command to install:
Install-Package cs-expert-system-shellUsage
The sample code below shows how to create a rule engine and initialize it with a set of rules:
using chen0040.ExpertSystem;
public RuleInferenceEngine getInferenceEngine()
{
RuleInferenceEngine rie = new RuleInferenceEngine();
Rule rule = new Rule("Bicycle");
rule.AddAntecedent(new IsClause("vehicleType", "cycle"));
rule.AddAntecedent(new IsClause("num_wheels", "2"));
rule.AddAntecedent(new IsClause("motor", "no"));
rule.setConsequent(new IsClause("vehicle", "Bicycle"));
rie.AddRule(rule);
rule = new Rule("Tricycle");
rule.AddAntecedent(new IsClause("vehicleType", "cycle"));
rule.AddAntecedent(new IsClause("num_wheels", "3"));
rule.AddAntecedent(new IsClause("motor", "no"));
rule.setConsequent(new IsClause("vehicle", "Tricycle"));
rie.AddRule(rule);
rule = new Rule("Motorcycle");
rule.AddAntecedent(new IsClause("vehicleType", "cycle"));
rule.AddAntecedent(new IsClause("num_wheels", "2"));
rule.AddAntecedent(new IsClause("motor", "yes"));
rule.setConsequent(new IsClause("vehicle", "Motorcycle"));
rie.AddRule(rule);
rule = new Rule("SportsCar");
rule.AddAntecedent(new IsClause("vehicleType", "automobile"));
rule.AddAntecedent(new IsClause("size", "medium"));
rule.AddAntecedent(new IsClause("num_doors", "2"));
rule.setConsequent(new IsClause("vehicle", "Sports_Car"));
rie.AddRule(rule);
rule = new Rule("Sedan");
rule.AddAntecedent(new IsClause("vehicleType", "automobile"));
rule.AddAntecedent(new IsClause("size", "medium"));
rule.AddAntecedent(new IsClause("num_doors", "4"));
rule.setConsequent(new IsClause("vehicle", "Sedan"));
rie.AddRule(rule);
rule = new Rule("MiniVan");
rule.AddAntecedent(new IsClause("vehicleType", "automobile"));
rule.AddAntecedent(new IsClause("size", "medium"));
rule.AddAntecedent(new IsClause("num_doors", "3"));
rule.setConsequent(new IsClause("vehicle", "MiniVan"));
rie.AddRule(rule);
rule = new Rule("SUV");
rule.AddAntecedent(new IsClause("vehicleType", "automobile"));
rule.AddAntecedent(new IsClause("size", "large"));
rule.AddAntecedent(new IsClause("num_doors", "4"));
rule.setConsequent(new IsClause("vehicle", "SUV"));
rie.AddRule(rule);
rule = new Rule("Cycle");
rule.AddAntecedent(new LessClause("num_wheels", "4"));
rule.setConsequent(new IsClause("vehicleType", "cycle"));
rie.AddRule(rule);
rule = new Rule("Automobile");
rule.AddAntecedent(new IsClause("num_wheels", "4"));
rule.AddAntecedent(new IsClause("motor", "yes"));
rule.setConsequent(new IsClause("vehicleType", "automobile"));
rie.AddRule(rule);
return rie;
}The sample code below shows how to use forward chaining in the rule engine to derive more facts from the known facts using rules:
RuleInferenceEngine rie = getInferenceEngine();
rie.AddFact(new IsClause("num_wheels", "4"));
rie.AddFact(new IsClause("motor", "yes"));
rie.AddFact(new IsClause("num_doors", "3"));
rie.AddFact(new IsClause("size", "medium"));
console.WriteLine("before inference");
console.WriteLine("{0}", rie.Facts);
console.WriteLine("");
rie.Infer(); //forward chain
console.WriteLine("after inference");
console.WriteLine("{0}", rie.Facts);
console.WriteLine("");The sample code below shows how to use the backward chaining to reach conclusion for a target variable given a set of known facts:
RuleInferenceEngine rie = getInferenceEngine();
rie.AddFact(new IsClause("num_wheels", "4"));
rie.AddFact(new IsClause("motor", "yes"));
rie.AddFact(new IsClause("num_doors", "3"));
rie.AddFact(new IsClause("size", "medium"));
console.WriteLine("Infer: vehicle");
List<Clause> unproved_conditions = new List<Clause>();
Clause conclusion = rie.Infer("vehicle", unproved_conditions);
console.WriteLine("Conclusion: " + conclusion);
Assert.Equal(conclusion.Value, "MiniVan");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:
RuleInferenceEngine rie = getInferenceEngine();
console.WriteLine("Infer with All Facts Cleared:");
rie.ClearFacts();
List<Clause> unproved_conditions = new List<Clause>();
Clause conclusion = null;
while (conclusion == null)
{
conclusion = rie.Infer("vehicle", unproved_conditions);
if (conclusion == null)
{
if (unproved_conditions.Count == 0)
{
break;
}
Clause c = unproved_conditions[0];
console.WriteLine("ask: " + c + "?");
unproved_conditions.Clear();
console.WriteLine("What is " + c.Variable + "?");
String value = Console.ReadLine();
rie.AddFact(new IsClause(c.Variable, value));
}
}
console.WriteLine("Conclusion: " + conclusion);
console.WriteLine("Memory: ");
console.WriteLine("{0}", rie.Facts);