private Vector3 get_force(ModelNode x, int node_index)
{
List <int> indices = x.AdjacencyIndices;
Vector3 total_force = Vector3.Zero;
for (int i = 0; i < x.EdgeCount; i++)
{
Adjacency current_edge = currentstate.GetEdge(indices[i]);
int relevant_index = current_edge.GetRelevantIndex(node_index);
ModelNode y = currentstate.GetNode(relevant_index);
Vector3 direction = new Vector3(x.CurrentLocation, y.CurrentLocation);
double eff_length = direction.Norm - current_edge.EquilibriumLength;
double total_magnitude = current_edge.SpringConstant * eff_length;
Vector3 current_force = (total_magnitude / direction.Norm) * direction;
//Vector3 current_force = direction;
total_force = total_force + current_force;
}
return(total_force - x.DampingCoefficient * x.CurrentVelocity);
}