/// <summary>
/// Adds the Edge to the underlying graph.
/// </summary>
/// <param name="edge">Edge to add.</param>
/// <returns></returns>
public Edge AddEdge(Edge edge)
{
base.AddEdge(edge);
return(edge);
}
/// <summary>Creates a new Edge.</summary>
/// <param name="source">Source for the.</param>
/// <param name="target">Target for the.</param>
/// <returns>An Edge.</returns>
public static Edge Create(Node source, Node target)
{
var e = new Edge { Source = source, Target = target };
source.Out.Add(e);
target.In.Add(e);
return e;
}
/// <summary>Defaults.</summary>
/// <param name="d">The Descriptor to process.</param>
/// <param name="x">The Vector to process.</param>
/// <param name="y">The Vector to process.</param>
/// <param name="activation">The activation.</param>
/// <returns>A Network.</returns>
public static Network Default(Descriptor d, Matrix x, Vector y, IFunction activation)
{
Network nn = new Network();
// set output to number of choices of available
// 1 if only two choices
int distinct = y.Distinct().Count();
int output = distinct > 2 ? distinct : 1;
// identity funciton for bias nodes
IFunction ident = new Ident();
// set number of hidden units to (Input + Hidden) * 2/3 as basic best guess.
int hidden = (int)System.Math.Ceiling((decimal)(x.Cols + output) * 2m / 3m);
// creating input nodes
nn.In = new Node[x.Cols + 1];
nn.In[0] = new Node {
Label = "B0", Activation = ident
};
for (int i = 1; i < x.Cols + 1; i++)
{
nn.In[i] = new Node {
Label = d.ColumnAt(i - 1), Activation = ident
}
}
;
// creating hidden nodes
Node[] h = new Node[hidden + 1];
h[0] = new Node {
Label = "B1", Activation = ident
};
for (int i = 1; i < hidden + 1; i++)
{
h[i] = new Node {
Label = String.Format("H{0}", i), Activation = activation
}
}
;
// creating output nodes
nn.Out = new Node[output];
for (int i = 0; i < output; i++)
{
nn.Out[i] = new Node {
Label = GetLabel(i, d), Activation = activation
}
}
;
// link input to hidden. Note: there are
// no inputs to the hidden bias node
for (int i = 1; i < h.Length; i++)
{
for (int j = 0; j < nn.In.Length; j++)
{
Edge.Create(nn.In[j], h[i]);
}
}
// link from hidden to output (full)
for (int i = 0; i < nn.Out.Length; i++)
{
for (int j = 0; j < h.Length; j++)
{
Edge.Create(h[j], nn.Out[i]);
}
}
return(nn);
}
