/// <summary>
/// Returns the mid-radius, in the induced geometry.
/// </summary>
public static double MidRadius(int p, int q, int r)
{
double pir = PiOverNSafe(r);
double inRadius = InRadius(p, q, r);
double midRadius = DonHatch.sinh(inRadius) / Math.Sin(pir);
switch (GetGeometry(p, q, r))
{
case Geometry.Hyperbolic:
return(DonHatch.asinh(midRadius));
case Geometry.Spherical:
return(Math.Asin(midRadius));
}
throw new System.NotImplementedException();
}