/// <summary>
/// Constructs a new NodeLink.
/// </summary>
public NodeLink(DynamicalNode to, DynamicalNode from, Complex weight, double decay, double plasticity)
{
this.To = to;
this.From = from;
this.Weight = weight;
this.Decay = decay;
this.Plasticity = plasticity;
}
/// <summary>
/// Addes a new incoming node to this node, with given decay and plasticity values.
/// </summary>
public bool AddIncomingNode(DynamicalNode node, Complex weight, double decay, double plasticity)
{
if (this.IncomingNodes.Any(link => link.From == node))
{
// Exists.
return(false);
}
this.IncomingNodes.Add(new NodeLink(this, node, weight, decay, plasticity));
return(true);
}
/// <summary>
/// Execute one iteration of integration, moving
/// the dynamical system forward in time by
/// the given delta time.
/// </summary>
public void Step(double deltaTime)
{
double h = deltaTime;
double halfH = deltaTime * 0.5;
double sixthH = deltaTime / 6.0;
double t00 = this.Time;
double t05 = this.Time + halfH;
double t10 = this.Time + h;
VectorOI y0 = _nodes.ToVectorOI(n => n, n => n.Value);
VectorOI k1 = _nodes.ToVectorOI(n => n, n => n.F(t00, y0));
VectorOI k1Blend = k1.MultiplyNew(halfH).AddSelf(y0);
VectorOI k2 = _nodes.ToVectorOI(n => n, n => n.F(t05, k1Blend));
VectorOI k2Blend = k2.MultiplyNew(halfH).AddSelf(y0);
VectorOI k3 = _nodes.ToVectorOI(n => n, n => n.F(t05, k2Blend));
VectorOI k3Blend = k3.MultiplyNew(h).AddSelf(y0);
VectorOI k4 = _nodes.ToVectorOI(n => n, n => n.F(t10, k3Blend));
// Perform final runge-kutta weighted average.
// We mutate k1, k2 and k3 here.
k2.MultiplySelf(2.0);
k3.MultiplySelf(2.0);
VectorOI y1 = k1.AddSelf(k2).AddSelf(k3).AddSelf(k4).MultiplySelf(sixthH).AddSelf(y0);
// Store results back into each node.
foreach (var kvp in y1)
{
DynamicalNode node = kvp.Key as DynamicalNode;
node.Value = kvp.Value;
}
this.Time = t10;
this.Iteration++;
}
/// <summary>
/// Addes a new incoming node to this node.
/// </summary>
public bool AddIncomingNode(DynamicalNode node)
{
return(AddIncomingNode(node, 1.0, 0, 0));
}
/// <summary>
/// Overridable method for printing the value of a node in this system.
/// </summary>
public virtual string FormatNodeValue(DynamicalNode node)
{
return(node.Value.ToString("F3"));
}
