/// <summary>
/// Sets the priors of BCC.
/// </summary>
/// <param name="workerCount">The number of workers.</param>
/// <param name="priors">The priors.</param>
protected virtual void SetPriors(int workerCount, Posteriors priors)
{
WorkerCount.ObservedValue = workerCount;
if (priors == null)
{
BackgroundLabelProbPrior.ObservedValue = Dirichlet.Uniform(LabelCount);
var confusionMatrixPrior = GetConfusionMatrixPrior();
ConfusionMatrixPrior.ObservedValue = Util.ArrayInit(workerCount, worker => Util.ArrayInit(LabelCount, lab => confusionMatrixPrior[lab]));
TrueLabelConstraint.ObservedValue = Util.ArrayInit(TaskCount, t => Discrete.Uniform(LabelCount));
}
else
{
BackgroundLabelProbPrior.ObservedValue = priors.BackgroundLabelProb;
ConfusionMatrixPrior.ObservedValue = priors.WorkerConfusionMatrix;
TrueLabelConstraint.ObservedValue = priors.TrueLabelConstraint;
}
}
public Posteriors Run(bool[] recoveredControl, bool[] recoveredTreated, bool showFactorGraph = false)
{
Engine.ShowFactorGraph = showFactorGraph;
// Set the observed values
numberControl.ObservedValue = recoveredControl.Length;
numberTreated.ObservedValue = recoveredTreated.Length;
this.recoveredControl.ObservedValue = recoveredControl;
this.recoveredTreated.ObservedValue = recoveredTreated;
var result = new Posteriors();
result.TreatmentHasEffect = Engine.Infer <Bernoulli>(model);
result.ProbIfControl = Engine.Infer <Beta>(probControl);
result.ProbIfTreated = Engine.Infer <Beta>(probTreated);
return(result);
}
/// <summary>
/// Infers the posteriors of BCC using the attached data and priors.
/// </summary>
/// <param name="taskIndices">The matrix of the task indices (columns) of each worker (rows).</param>
/// <param name="workerLabels">The matrix of the labels (columns) of each worker (rows).</param>
/// <param name="priors">The priors of the BCC parameters.</param>
/// <returns></returns>
public virtual Posteriors Infer(int[][] taskIndices, int[][] workerLabels, Posteriors priors)
{
int workerCount = workerLabels.Length;
SetPriors(workerCount, priors);
AttachData(taskIndices, workerLabels, null);
var result = new Posteriors();
Engine.NumberOfIterations = NumberOfIterations;
result.Evidence = Engine.Infer <Bernoulli>(Evidence);
result.BackgroundLabelProb = Engine.Infer <Dirichlet>(BackgroundLabelProb);
result.WorkerConfusionMatrix = Engine.Infer <Dirichlet[][]>(WorkerConfusionMatrix);
result.TrueLabel = Engine.Infer <Discrete[]>(TrueLabel);
result.TrueLabelConstraint = Engine.Infer <Discrete[]>(TrueLabel, QueryTypes.MarginalDividedByPrior);
// Prediction mode is indicated by none of the workers having a label.
// We can just look at the first one
if (workerLabels[0] == null)
{
result.WorkerPrediction = Engine.Infer <Discrete[][]>(WorkerLabel);
}
return(result);
}
