public void GetLikelyhood(DataSample sample, double[] result)
{
var probabilities = result;
for (int index = 0; index < probabilities.Length; index++)
{
probabilities[index] = _classesProbablityDistribution.GetLogProbability(index);
foreach (var dataPoint in sample.DataPoints)
{
var value = Convert.ToDouble(dataPoint.Value);
probabilities[index] = probabilities[index] +
_distribution[index, dataPoint.ColumnId].GetLogProbability(value);
}
}
}
public void GetLikelyhoodNaiveBayes(DataSample sample, ClassLikelyhood[] result)
{
var probabilities = result;
for (int index = 0; index < Classes; index++)
{
probabilities[index].Value = _classesProbablityDistribution.GetLogProbability(index);
probabilities[index].ClassId = index;
foreach (var dataPoint in sample.DataPoints)
{
var value = Convert.ToDouble(dataPoint.Value);
probabilities[index].Value = probabilities[index].Value +
_distribution[index, dataPoint.ColumnId].GetLogProbability(value);
}
}
Array.Sort(result, 0, Classes, _comparerLikelyhood);
}
public string Compute(IDataRow datarow)
{
var probabilities = new double[_data.ClassesValue.Length];
var attributes = datarow.Attributes.ToArray();
var doubleConverter = new DoubleConverter();
var maxProbabilityIndex = 0;
for (int index = 0; index < probabilities.Length; index++)
{
probabilities[index] = 1;
for (int columnIndex = 0; columnIndex < _data.Attributes.Length; columnIndex++)
{
if (attributes[columnIndex] == TableData.ClassAttributeName)
{
probabilities[index] = _classesProbablityDistribution.GetLogProbability(index);
continue;
}
var value = datarow[attributes[columnIndex]];
if (!value.IsNumeric())
{
probabilities[index] = probabilities[index] + _distribution[index, columnIndex].GetLogProbability(_data.GetSymbol((string)value, columnIndex));
}
else
{
probabilities[index] = probabilities[index] + _distribution[index, columnIndex].GetLogProbability(doubleConverter.Convert(value));
}
}
if (probabilities[maxProbabilityIndex] < probabilities[index])
{
maxProbabilityIndex = index;
}
}
return(_data.ClassesValue[maxProbabilityIndex]);
}