// Main function which does all the steps AQ11 takes to generate rules
public Rule ruleInference()
{
// AQ11 inputs
// Positive examples E1
List <Example> positiveExamples = examples.FindAll(example => example.groupClass == groupClass);
// Negative examples E2
List <Example> negativeExamples = examples.Except(positiveExamples).ToList();
// Data member for the most specific wrappers ei/ej(positive vs negative example)
List <List <Disjunction> > firstLevelClausules = new List <List <Disjunction> >();
// Data member for the more general wrappers ei/E2(positive example vs negative class)
List <Conjunction> secondLevelClausules = new List <Conjunction>();
// Data member indicting which examples were already covered by generated wrappers and thus
// no longer need to be analyzed
List <int> skipList = new List <int>();
// AQ11 runs through all positive examples
for (int i = 0; i < positiveExamples.Count; i++)
{
// Replaces "remove all positive examples covered by any ei/E2 wrapper" to avoid
// problems with modifying the list that is currently being iterated
if (skipList.Exists(num => num == i))
{
continue;
}
Example pos = positiveExamples[i];
firstLevelClausules.Add(new List <Disjunction>());
// Generate ei/ej wrapper for every negative example
for (int j = 0; j < negativeExamples.Count; j++)
{
Example neg = negativeExamples[j];
// Each wrapper consists of a disjunction of inequalities
List <LogicalArgument> ineqs = new List <LogicalArgument>();
for (int k = 0; k < pos.attributes.Count; k++)
{
// Inequality for each separate attribute is generated if the positive and negative
// examples do not share the same value in it
if (pos.attributes[k].value != neg.attributes[k].value)
{
Variable var = new Variable(pos.attributes[k].name);
Constant cons = new Constant(neg.attributes[k].value);
Inequality ineq = new Inequality(var, cons);
ineqs.Add(ineq);
}
}
// Disjunction is created for all generated inequalities and added to correct data member
Disjunction disj = new Disjunction(ineqs);
firstLevelClausules[firstLevelClausules.Count - 1].Add(disj);
}
// Generates ei/E2 wrapper for the current positive example as conjunction of all
// ei/ej wrappers and by applying the absorb rule
secondLevelClausules.Add(applyAbsorbRule(firstLevelClausules[firstLevelClausules.Count - 1]));
// Using the newly generated ei/E2 wrapper, skip list is updated to include positive examples
// covered by it
skipList.AddRange(skipCoveredExamples(secondLevelClausules[secondLevelClausules.Count - 1], positiveExamples, i));
}
// All ei/E2 wrappers are merged using disjunctions in a final rule wrapper E1/E2
Rule rule = new Rule(secondLevelClausules, groupClass);
return(rule);
}
private List <LogicalArgument> equalitiesInference(List <LogicalArgument> result)
{
// Builds an attribute map containing:
// 1.) names of all attributes
// 2.) all possible values for each attribute present in the training set
AttributeValueMap[] maps = new AttributeValueMap[examples[0].attributes.Count];
for (int i = 0; i < maps.Length; i++)
{
// Uses the first example as a map prototype for the attribute names
maps[i] = new AttributeValueMap(examples[0].attributes[i].name, examples[0].attributes[i].type);
}
foreach (Example ex in examples)
{
// Runs through all examples and saves their unique attribute values in appropriate maps
for (int i = 0; i < ex.attributes.Count; i++)
{
Attribute atr = ex.attributes[i];
if (maps[i].values.Exists(val => val == atr.value) == false)
{
maps[i].values.Add(atr.value);
}
}
}
// Builds an attribute map containing:
// 1.) names of all attributes present in the grouped up unabsorbed disjuncts
// 2.) values of the attributes present in the unabsorbed inequalities
List <AttributeValueMap> resultMap = new List <AttributeValueMap>();
foreach (LogicalArgument arg in result)
{
if (arg.GetType().Name == "Inequality")
{
Inequality ineq = (Inequality)arg;
if (ineq.firstArgument.GetType().Name == "Variable")
{
// Variable name represents the attribute name
Variable var = (Variable)ineq.firstArgument;
// Constant name represents the attribute value
Constant cons = (Constant)ineq.secondArgument;
bool mapFound = false;
foreach (AttributeValueMap map in resultMap)
{
// If attribute map is found for the given name
// it adds its value if its not yet listed in the map
if (map.name == var.name)
{
foreach (string value in cons.valueSet)
{
if (map.values.Exists(val => val == value) == false)
{
mapFound = true;
map.values.Add(value);
}
}
}
}
// If no map is found for attribute of the given name
if (!(mapFound))
{
// New map is created using data from the full attribute map generated from training set
AttributeType type = maps.ToList().Find(m => m.name == var.name).type;
AttributeValueMap map = new AttributeValueMap(var.name, type);
map.values.AddRange(cons.valueSet);
resultMap.Add(map);
}
}
}
}
// Inequalities are changed to equalities for better readability
List <LogicalArgument> output = new List <LogicalArgument>();
foreach (AttributeValueMap map in resultMap)
{
AttributeValueMap candidate = maps.ToList().Find(m => m.name == map.name);
if (candidate != null)
{
Variable var = new Variable(map.name);
List <string> missingValues = new List <string>();
// Aquires all values allowed by the inequality from the attributemap
foreach (string value in candidate.values)
{
if (map.values.Exists(val => val == value) == false)
{
missingValues.Add(value);
}
}
// Builds equation from the missing values and adds it to the final output
Constant cons = new Constant(missingValues);
Equality eq = new Equality(var, cons);
output.Add(eq);
}
}
return(output);
}
