private Vector2 ForceDirectedRepulsion(GraphVertex vertex, float repulsion)
{
IEnumerable <GraphEdge> inEdges;
_project.DependencyGraph.TryGetInEdges(vertex, out inEdges);
List <GraphEdge> edgeList = inEdges.ToList();
Vector2 force = Vector2.zero;
foreach (GraphVertex other in _project.DependencyGraph.Vertices)
{
GraphEdge edge = edgeList.Find(x => (x.Source == other) || (x.Target == other));
if (other == vertex || edge != null)
{
continue;
}
Vector2 direction = _simulationData[vertex].position - _simulationData[other].position;
float distanceToBounds = direction.magnitude - (vertex.Island.Radius + other.Island.Radius);
if (distanceToBounds < 0.0f)
{
Vector2 constrainedPosition = _simulationData[vertex].position - direction.normalized * distanceToBounds;
_simulationData[other] = new VertexPositionData(constrainedPosition, constrainedPosition);
distanceToBounds = 0f;
}
float divisor = distanceToBounds + 0.1f;
force += (direction.normalized * repulsion) / (divisor * divisor);
}
return(force);
}
public void BuildForceDirectedLayout(OSGiProject project)
{
_simulationData = new Dictionary <GraphVertex, VertexPositionData>();
_project = project;
// TODO: Refactor
float attraction = 10.0f;
float spring = 1.0f;
float repulsion = 5.0f;
float attractToCenter = 0.005f;
float friction = 0.105f;
float timestep = StepSize;
foreach (GraphVertex vertex in project.DependencyGraph.Vertices)
{
float rr = 20f;
float x = (SyncDataStorage.Instance.GetRandomNumber(_random) - 0.5f) * rr;
float y = (SyncDataStorage.Instance.GetRandomNumber(_random) - 0.5f) * rr;
Vector2 startPos = new Vector2(x, y);
VertexPositionData vertexData = new VertexPositionData(startPos, startPos);
_simulationData.Add(vertex, vertexData);
}
int stepCounter = 0;
while (stepCounter < SimulationSteps)
{
foreach (GraphVertex vertex in project.DependencyGraph.Vertices)
{
Vector2 netForce = Vector2.zero;
netForce += ForceDirectedAttraction(vertex, attraction, spring);
netForce += ForceDirectedRepulsion(vertex, repulsion);
netForce -= ForceDirectedAttractToCenter(vertex, attractToCenter);
VerletIntegration(vertex, netForce, friction, timestep);
netForce = new Vector2((float)Math.Truncate(netForce.x * 10) / 10, (float)Math.Truncate(netForce.y * 10) / 10);
stepCounter++;
}
}
foreach (GraphVertex vertex in project.DependencyGraph.Vertices)
{
VertexPositionData vertexData = _simulationData[vertex];
Vector3 pos = new Vector3(vertexData.position.x, 0, vertexData.position.y);
vertex.Position = pos;
}
}
private void VerletIntegration(GraphVertex vertex, Vector2 force, float friction, float timestep)
{
Vector2 posDiff = _simulationData[vertex].position - _simulationData[vertex].oldPosition;
Vector2 velocity = posDiff / timestep;
Vector2 resistance = velocity * timestep * friction;
Vector2 oldPosition = _simulationData[vertex].position;
Vector2 newPosition = 2.0f * _simulationData[vertex].position - _simulationData[vertex].oldPosition
+ timestep * timestep * force;
newPosition -= resistance;
VertexPositionData vertexData = new VertexPositionData(newPosition, oldPosition);
_simulationData[vertex] = vertexData;
}
private void computeForceDirectedLayoutThreaded(int simulationSteps, float stepSize)
{
status = Status.Working;
Debug.Log("Starting forcedirected graph layout construction.");
//Attract Strength multi
float c1 = 10.0f;
//"Spring" length for maximal dependency strength
float c3 = 1.0f;
//Repulsion
float c4 = 5.0f;
//Attract-To-Center
float c5 = 0.005f;
//Friction
float c6 = 0.105f;
//TimeStep
float t = stepSize;
Dictionary <GraphVertex, VertexPositionData> simulationData = new Dictionary <GraphVertex, VertexPositionData>();
#region init start values
foreach (GraphVertex vert in graph.Vertices)
{
float rr = 20f;
Vector2 startPos = new Vector2((float)RNG.NextDouble() * rr, (float)RNG.NextDouble() * rr);
VertexPositionData vpd = new VertexPositionData(startPos, startPos);
simulationData.Add(vert, vpd);
}
#endregion
int stepCounter = 0;
while (stepCounter < simulationSteps)
{
foreach (GraphVertex thisVert in graph.Vertices)
{
// total force affecting "thisVert"
Vector2 netForce = Vector2.zero;
#region Attraction
IEnumerable <GraphEdge> outEdges;
graph.TryGetOutEdges(thisVert, out outEdges);
List <GraphEdge> edgeList = outEdges.ToList();
Vector2 springForce = Vector2.zero;
foreach (GraphEdge importEdge in edgeList)
{
GraphVertex otherVert = importEdge.Target;
Vector2 direction = simulationData[otherVert].position - simulationData[thisVert].position;
float springEquilibriumLength = (thisVert.getIsland().getRadius() + otherVert.getIsland().getRadius()) + c3 * (project.getMaxImportCount() / importEdge.getWeight());
springForce += c1 * direction.normalized * Mathf.Log((direction.magnitude / springEquilibriumLength));
}
IEnumerable <GraphEdge> inEdges;
graph.TryGetInEdges(thisVert, out inEdges);
edgeList = inEdges.ToList();
/*
* foreach (GraphEdge exportEdge in edgeList)
* {
* GraphVertex otherVert = exportEdge.Source;
* Vector2 direction = simulationData[otherVert].position - simulationData[thisVert].position;
*
* float springEquilibriumLength = (thisVert.getIsland().getRadius() + otherVert.getIsland().getRadius()) + c3 / exportEdge.getWeight();
*
* springForce += c1 * direction.normalized * Mathf.Log((direction.magnitude / springEquilibriumLength));
* }
*/
netForce += springForce;
#endregion
#region Repulsion
foreach (GraphVertex otherVert in graph.Vertices)
{
if (otherVert == thisVert || (edgeList.Find(x => (x.Source == otherVert) || (x.Target == otherVert))) != null)
{
continue;
}
Vector2 direction = simulationData[thisVert].position - simulationData[otherVert].position;
float distanceToBounds = direction.magnitude - (thisVert.getIsland().getRadius() + otherVert.getIsland().getRadius());
if (distanceToBounds < 0.0f)
{
Vector2 constrainedPosition = simulationData[thisVert].position - direction.normalized * distanceToBounds;
simulationData[thisVert] = new VertexPositionData(constrainedPosition, constrainedPosition);
distanceToBounds = 0f;
}
netForce += (direction.normalized * c4) / (Mathf.Pow(distanceToBounds + 0.1f, 2f));
}
#endregion
#region Attract-to-Center
netForce -= simulationData[thisVert].position * c5;
#endregion
#region position computation through Verlet-Integration
Vector2 currentVelocity = (simulationData[thisVert].position - simulationData[thisVert].oldPosition) / t;
Vector2 resistance = currentVelocity * t * c6;
Vector2 newPosition = 2.0f * simulationData[thisVert].position - simulationData[thisVert].oldPosition + t * t * netForce;
newPosition -= resistance;
Vector2 oldPosition = simulationData[thisVert].position;
VertexPositionData vpd = new VertexPositionData(newPosition, oldPosition);
simulationData[thisVert] = vpd;
#endregion
stepCounter++;
}
}
#region assign computed positions to graph vertices
foreach (GraphVertex vert in graph.Vertices)
{
VertexPositionData vpd = simulationData[vert];
Vector3 pos = new Vector3(vpd.position.x, 0, vpd.position.y);
vert.setPosition(pos);
}
#endregion
status = Status.Finished;
Debug.Log("Forcedirected Graph layout is computed!");
cb();
}
