/// <summary>
/// Normalize a row vector using the hyperbolic tangent (tanh)function.
/// </summary>
/// <param name="row"></param>
/// <param name="properties"></param>
/// <returns></returns>
public Vector Normalize(Vector row, numl.Math.Summary properties)
{
if (row == null)
{
throw new ArgumentNullException("Row was null");
}
double[] item = new double[row.Length];
for (int i = 0; i < row.Length; i++)
{
item[i] = this.Tangent.Compute(row[i]);
}
return item;
}
/// <summary>
/// Normalize a row vector using Z-Score normalization on the supplied feature properties.
/// </summary>
/// <param name="row"></param>
/// <param name="properties"></param>
/// <returns></returns>
public Vector Normalize(Vector row, numl.Math.Summary properties)
{
if (row == null)
{
throw new ArgumentNullException("Row was null");
}
double[] item = new double[row.Length];
for (int i = 0; i < row.Length; i++)
{
item[i] = (row[i] - properties.Average[i]) / properties.StandardDeviation[i];
item[i] = (double.IsNaN(item[i]) || double.IsInfinity(item[i]) ? 0d : item[i]);
}
return item;
}
/// <summary>
/// Update and return the new Theta value.
/// </summary>
/// <param name="properties">Properties for the optimization routine.</param>
/// <returns></returns>
public override Vector UpdateTheta(numl.Math.Optimization.OptimizerProperties properties)
{
Vector v = (this.Momentum * properties.Theta) - (properties.LearningRate * properties.Gradient);
return properties.Theta + this.Momentum * v - properties.LearningRate * properties.Gradient;
}