public void ComputeRadius(Node parentNode)
{
//bottom up algorithm. (From leaf to root)
//With given leaf size, calculate parent hemsphere size and recursively compute upper level hemsphere size
if (parentNode.nodeNumDecendents == 0)
{
parentNode.nodeHemsphereRadius = leafRadius;
return;
}
else
{
float parentHemsphereArea = 0.0f; //Hp = sum of pi*r^2
foreach (Node child in parentNode.nodeChildren)
{
ComputeRadius(child); //recursive bottom up call
//Euclidean Space Case for understnding:
//parentHemsphereArea += Mathf.Pow(child.nodeHemsphereRadius, 2);
//Hyperbolic Space Case:
//H3Math.TWO_PI * (H3Math.cosh(r / K) - 1.0);
//parentHemsphereArea += (float)(Math.PI * 2 * (Math.Cosh(child.nodeHemsphereRadius / 2) - 1));
parentHemsphereArea += (float)(Math.Cosh(child.nodeHemsphereRadius) - 1);
}
//Euclidean Space Case:
//parentNode.nodeHemsphereRadius = Mathf.Sqrt(parentHemsphereArea);
//Hyperbolic Space Case:
//K * H3Math.asinh(Math.sqrt(area / (H3Math.TWO_PI * K * K)));
//parentNode.nodeHemsphereRadius = (float)HyperbolicMath.ASinh(Math.Sqrt(parentHemsphereArea / (Math.PI * 2 * 4))) * 2;
parentNode.nodeHemsphereRadius = (float)HyperbolicMath.ASinh(Math.Sqrt(parentHemsphereArea));
}
return;
}
