/// <inheritdoc />
protected override bool Calculate(ReadOnlyArrayView <Body> bodies, ReadOnlyArrayView <int> indices, ArrayView <Vector3d> deltas)
{
int n = indices.Count;
// check if sufficient number of bodies
if (n < 3)
{
deltas.Clear();
return(false);
}
var sum = new Vector3d();
for (int i = 1; i < n; i++)
{
sum += bodies[indices[i]].Position.Current;
}
var t = 1.0 / (n - 1);
var d = (sum * t - bodies[indices[0]].Position.Current) * 0.5;
// apply projection to center
deltas[0] = d;
d *= -t;
// distribute reverse among 1 ring
for (int i = 1; i < n; i++)
{
deltas[i] = d;
}
return(true);
}
/// <inheritdoc />
protected override bool Calculate(ReadOnlyArrayView <Body> bodies, ReadOnlyArrayView <int> indices, ArrayView <Vector3d> deltas)
{
int n = indices.Count;
if (n < 4 || !Geometry.FitPlaneToPoints(Indices.Select(i => bodies[i].Position.Current), out Vector3d p, out Vector3d z))
{
deltas.Clear();
return(false);
}
for (int i = 0; i < n; i++)
{
deltas[i] = Vector3d.Project(p - bodies[indices[i]].Position.Current, z);
}
return(true);
}
/// <inheritdoc />
protected override bool Calculate(ReadOnlyArrayView <Body> bodies, ReadOnlyArrayView <int> indices, ArrayView <Vector3d> deltas)
{
int n = indices.Count;
if (n < 4 || !Geometry.FitSphereToPoints(Indices.Select(i => bodies[i].Position.Current), out Vector3d p, out double r))
{
deltas.Clear();
return(false);
}
for (int i = 0; i < n; i++)
{
var d = p - bodies[indices[i]].Position.Current;
deltas[i] = d * (1.0 - r / d.Length);
}
return(true);
}
/// <inheritdoc />
protected override bool Calculate(ReadOnlyArrayView <Body> bodies, ReadOnlyArrayView <int> indices, ArrayView <Vector3d> deltas)
{
int n = indices.Count;
if (n < 2)
{
deltas.Clear();
return(false);
}
var p = Indices.Select(i => bodies[i].Position.Current).Mean();
for (int i = 0; i < n; i++)
{
deltas[i] = p - bodies[indices[i]].Position.Current;
}
return(true);
}
/// <summary>
///
/// </summary>
/// <param name="bodies"></param>
/// <param name="indices"></param>
/// <param name="deltas"></param>
/// <returns></returns>
protected override bool Calculate(ReadOnlyArrayView <Body> bodies, ReadOnlyArrayView <int> indices, ArrayView <Vector3d> deltas)
{
int n = indices.Count;
// check if sufficient number of bodies
if (n < 4)
{
deltas.Clear();
return(false);
}
var target = 0.0;
// calculate target as mean length
for (int i = 0; i < n; i += 2)
{
var d = bodies[indices[i + 1]].Position.Current - bodies[indices[i]].Position.Current;
var m = d.Length;
target += m;
// cache to avoid redundant calcs
deltas[i] = d;
deltas[i + 1].X = m;
}
target /= n >> 1;
// calculate deltas
for (int i = 0; i < n; i += 2)
{
var d = deltas[i];
var m = deltas[i + 1].X;
d *= (1.0 - target / m) * 0.5;
deltas[i] = d;
deltas[i + 1] = -d;
}
return(true);
}
