示例#1
0
def Qparameter(parts, distfunc=None):
    """
    Calculates the minimum spanning tree Q parameter (Cartwright & Whitworth 2004)
    for a projection of the particle set.
    
    :argument distfunc:  distfunc is the distance function which can be used to select
    the projection plane.

    """
    if distfunc is None:

        def distfunc(p, q):
            return (((p.x - q.x)**2 + (p.y - q.y)**2)**0.5).value_in(p.x.unit)

    N = len(parts)

    graph = Graph()

    for p in parts:
        d = distfunc(p, parts)
        for i, q in enumerate(parts):
            if p != q:
                graph.add_edge(p, q, d[i])

    all_edges = graph.all_edges()

    ml = reduce(lambda x, y: x + y[0], all_edges, zero) / len(all_edges)

    mst = MinimumSpanningTreeFromEdges(all_edges)

    mlmst = reduce(lambda x, y: x + y[0], mst, zero) / len(mst)
    # normalize
    mlmst = mlmst / (N * numpy.pi)**0.5 * (N - 1)

    return mlmst / ml
def Qparameter(parts, distfunc=None):
    """
    Calculates the minimum spanning tree Q parameter (Cartwright & Whitworth 2004)
    for a projection of the particle set.
    
    :argument distfunc:  distfunc is the distance function which can be used to select
    the projection plane.

    """
    if distfunc is None:
      def distfunc(p,q):
        return (((p.x-q.x)**2+(p.y-q.y)**2)**0.5).value_in(p.x.unit)
    N=len(parts)
  
    graph=Graph()
  
    for p in parts:
      d=distfunc(p,parts)
      for i,q in enumerate(parts):
        if p!=q:
          graph.add_edge(p,q, d[i] ) 

    all_edges=graph.all_edges()
  
    ml=reduce(lambda x,y: x+y[0],all_edges,zero )/len(all_edges)
  
    mst=MinimumSpanningTreeFromEdges(all_edges)
  
    mlmst=reduce(lambda x,y: x+y[0],mst, zero )/len(mst)
# normalize  
    mlmst=mlmst/(N*numpy.pi)**0.5*(N-1)
  
    return mlmst/ml
示例#3
0
def connected_components(parts, treshold=None, distfunc=None):
    if distfunc is None:

        def distfunc(p, q):
            return ((p.x - q.x)**2 + (p.y - q.y)**2 + (p.z - q.z)**2)**0.5

    print "making graph"
    graph = Graph()
    for p in parts:
        graph.add_node(p)
        d = distfunc(p, parts)
        edges = [(d[i], p, q) for i, q in enumerate(parts) if p != q]
        edges = filter(lambda x: x[0] < treshold, edges)
        for e in edges:
            graph.add_edge(e[1], e[2], e[0])
    print "done"
    cc = ConnectedComponents(graph)
    print "number of edges:", len(graph.all_edges())
    print "number of CC:", len(cc)
    return graph, cc