# Revision history [back]

So I wrote a few lines that do what I wanted:

def angle(x):
return sign(x[1])*(x[0])/(x.norm())
def get_rotation_system(H):
if not(H.get_pos()):
return 'no positions known'
rotation_system=dict()
for v in H.vertex_iterator():
anglelist=[[angle(vector(H.get_pos()[w])-(vector(H.get_pos()[v]))),w] for w in H[v]]
anglelist.sort()
rotation_system[v]=[w for a,w in anglelist]
H.set_embedding(rotation_system)


This can be used as follows:

G = Graph({0:[1,5,3,4],1:[2,0,3],2:[1,4,5],3:[0,1],4:[0,2,5],5:[0,2,4]})
G.set_pos({0:[213,281],1:[93,171],2:[189,35],3:[35,315],4:[315,146],5:[197,158]})
get_rotation_system(G)
G.show(layout='planar')


Anyhow I think this would be a handy function to have, especially in combination with the graph editor. I will open a trac ticket soon.

So I wrote a few lines that do what I wanted:

def angle(x):
return sign(x[1])*(x[0])/(x.norm())
arccos(sign(x[1])*(x[0])/(x.norm()))
def get_rotation_system(H):
if not(H.get_pos()):
return 'no positions known'
rotation_system=dict()
for v in H.vertex_iterator():
anglelist=[[angle(vector(H.get_pos()[w])-(vector(H.get_pos()[v]))),w] for w in H[v]]
anglelist.sort()
rotation_system[v]=[w for a,w in anglelist]
H.set_embedding(rotation_system)


This can be used as follows:

G = Graph({0:[1,5,3,4],1:[2,0,3],2:[1,4,5],3:[0,1],4:[0,2,5],5:[0,2,4]})
G.set_pos({0:[213,281],1:[93,171],2:[189,35],3:[35,315],4:[315,146],5:[197,158]})
get_rotation_system(G)
G.show(layout='planar')


Anyhow I think this would be a handy function to have, especially in combination with the graph editor. I will open a trac ticket soon.