tvl-depot/universe/data_structures_and_algorithms/graph-to-graphviz.py

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from graphviz import Digraph
from collections import deque
from fixtures import weighted_graph
# There are three ways to model a graph:
# 1. Edge list: [(Vertex, Vertex)]
# 2. Neighbors table: Map(Vertex, [Vertex])
# 3. Adjacency matrix: [[Boolean]]
#
# The following graph is a neighbors table.
# to_graphviz :: Vertex -> Map(Vertex, [(Vertex, Weight)]) -> String
def to_graphviz(start, g):
"""Compiles the graph into GraphViz."""
d = Digraph()
q = deque()
seen = set()
q.append(start)
while q:
v = q.popleft()
if v in seen:
continue
d.node(v, label=v)
for w, x in g[v]:
d.edge(v, x, label=str(w))
q.append(x)
seen.add(v)
return d.source
with open('/tmp/test.gv', 'w') as f:
src = to_graphviz('a', weighted_graph)
f.write(src)
print('/tmp/test.gv created!')