/// <summary>
/// Centroid method to obtain the numerical representation of a fuzzy output. The numerical
/// value will be the center of the shape formed by the several fuzzy labels with their
/// constraints.
/// </summary>
///
/// <param name="fuzzyOutput">A <see cref="FuzzyOutput"/> containing the output of several
/// rules of a Fuzzy Inference System.</param>
/// <param name="normOperator">A <see cref="INorm"/> operator to be used when constraining
/// the label to the firing strength.</param>
///
/// <returns>The numerical representation of the fuzzy output.</returns>
///
/// <exception cref="Exception">The numerical output is unavaliable. All memberships are zero.</exception>
///
public float Defuzzify( FuzzyOutput fuzzyOutput, INorm normOperator )
{
// results and accumulators
float weightSum = 0, membershipSum = 0;
// speech universe
float start = fuzzyOutput.OutputVariable.Start;
float end = fuzzyOutput.OutputVariable.End;
// increment
float increment = ( end - start ) / this.intervals;
// running through the speech universe and evaluating the labels at each point
for ( float x = start; x < end; x += increment )
{
// we must evaluate x membership to each one of the output labels
foreach ( FuzzyOutput.OutputConstraint oc in fuzzyOutput.OutputList )
{
// getting the membership for X and constraining it with the firing strength
float membership = fuzzyOutput.OutputVariable.GetLabelMembership( oc.Label, x );
float constrainedMembership = normOperator.Evaluate( membership, oc.FiringStrength );
weightSum += x * constrainedMembership;
membershipSum += constrainedMembership;
}
}
// if no membership was found, then the membershipSum is zero and the numerical output is unknown.
if ( membershipSum == 0 )
throw new Exception( "The numerical output in unavaliable. All memberships are zero." );
return weightSum / membershipSum;
}
public double Defuzzify(FuzzyOutput fuzzyOutput, INorm normOperator)
{
// results and accumulators
double weightSum = 0, membershipSum = 0;
// speech universe
double start = fuzzyOutput.OutputVariable.Start;
double end = fuzzyOutput.OutputVariable.End;
// increment
double increment = (end - start) / intervals;
// running through the speech universe and evaluating the labels at each point
for (double x = start; x < end; x += increment)
{
// we must evaluate x membership to each one of the output labels
foreach (FuzzyOutput.OutputConstraint oc in fuzzyOutput.OutputList)
{
// getting the membership for X and constraining it with the firing strength
double membership = fuzzyOutput.OutputVariable.GetLabelMembership(oc.Label, x);
double constrainedMembership = normOperator.Evaluate(membership, oc.FiringStrength);
weightSum += x * constrainedMembership;
membershipSum += constrainedMembership;
}
}
// if no membership was found, then the membershipSum is zero and the numerical output is unknown.
if (membershipSum == 0)
{
return(0);
}
return(weightSum / membershipSum);
}
private void SetSystemOutput(FuzzyOutput fuzzyOutput)
{
if (fuzzyOutput.OutputList.Count != 0)
{
_systemOutputValue = _centroidDefuzzifier.Defuzzify(fuzzyOutput, new MinimumNorm());
_systemOutputPercentage = fuzzyOutput.OutputList.Max(x => x.FiringStrength);
_systenOutputName = fuzzyOutput.OutputList.First(x => x.FiringStrength == _systemOutputPercentage).Label;
}
else
{
_systemOutputValue = float.NaN;
_systenOutputName = "STOP";
_systemOutputPercentage = 1;
}
}
private Dictionary <string, float> GetOutput()
{
Dictionary <string, float> output = new Dictionary <string, float>();
FuzzyOutput fuzzyOutput = _system.ExecuteInference(_outputName);
foreach (var oc in fuzzyOutput.OutputList)
{
if (!output.ContainsKey(oc.Label))
{
output.Add(oc.Label, oc.FiringStrength);
}
else if (output[oc.Label] < oc.FiringStrength)
{
output[oc.Label] = oc.FiringStrength;
}
}
SetSystemOutput(fuzzyOutput);
return(output);
}
/// <summary>
/// Executes the fuzzy inference, obtaining the <see cref="FuzzyOutput"/> of the system for the required
/// <see cref="LinguisticVariable"/>.
/// </summary>
///
/// <param name="variableName">Name of the <see cref="LinguisticVariable"/> to evaluate.</param>
///
/// <returns>A <see cref="FuzzyOutput"/> containing the fuzzy output of the system for the
/// <see cref="LinguisticVariable"/> specified in <paramref name="variableName"/>.</returns>
///
/// <exception cref="KeyNotFoundException">The variable indicated was not found in the database.</exception>
///
public FuzzyOutput ExecuteInference( string variableName )
{
// gets the variable
LinguisticVariable lingVar = database.GetVariable( variableName );
// object to store the fuzzy output
FuzzyOutput fuzzyOutput = new FuzzyOutput( lingVar );
// select only rules with the variable as output
Rule[] rules = rulebase.GetRules( );
foreach ( Rule r in rules )
{
if ( r.Output.Variable.Name == variableName )
{
string labelName = r.Output.Label.Name;
float firingStrength = r.EvaluateFiringStrength( );
if ( firingStrength > 0 )
fuzzyOutput.AddOutput( labelName, firingStrength );
}
}
// returns the fuzzy output obtained
return fuzzyOutput;
}
