def test_kruskal(self):
# https://en.wikipedia.org/wiki/Kruskal%27s_algorithm
gr = graph.UGraph()
a = graph.Node('a')
b = graph.Node('b')
c = graph.Node('c')
d = graph.Node('d')
e = graph.Node('e')
f = graph.Node('f')
g = graph.Node('g')
gr.addnodes(a, b, c, d, e, f, g)
gr.addedge(a, d, 5)
gr.addedge(a, b, 7)
gr.addedge(b, c, 8)
gr.addedge(b, d, 9)
gr.addedge(b, e, 7)
gr.addedge(c, e, 5)
gr.addedge(d, e, 15)
gr.addedge(d, f, 6)
gr.addedge(f, e, 8)
gr.addedge(e, g, 9)
gr.addedge(f, g, 11)
mst = graph.kruskal(gr)
for ex in mst.edges():
print ex
def set_mst(coords_sph, a0):
""" Computes the mst, using graph objects, from the transformed coordinates
"""
vertices_sph = [graph.Vertex(coord) for coord in coords_sph]
mst_sph = graph.kruskal(vertices_sph)
return mst_sph
force_heads = force_heads[0::skips]
#keep = np.random.choice(len(force_heads), 320)
#force_tails = force_tails[keep]
#force_heads = force_heads[keep]
# rescale the force_heads so the biggest one is length 1 for plotting
M = np.max(np.linalg.norm(force_heads, axis = 1))
force_heads *= 1/M
# get the COM
com = myfloc.coords_sph * myfloc.a0
# get the mst (floc functions keep it as a sphere)
vertices = [graph.Vertex(coord) for coord in com]
mst = graph.kruskal(vertices)
# write the data
import csv
ofile = open("3d_com.csv", "w")
writer = csv.writer(ofile)
for row in com:
writer.writerow([row[0],row[1],row[2]])
ofile.close()
ofile = open("3d_mst.csv","w")
writer = csv.writer(ofile)
for edge in mst:
writer.writerow( [ edge.u.coords[0] , edge.u.coords[1] , edge.u.coords[2] ] )