Pygraphviz中创建的重复边

Question

我正在使用PyGraphviz生成一个具有多个级别和节点的分层树状结构。每当我尝试在两个节点之间创建边缘时（我将唯一索引分配给树中的每个节点），Pygraphviz会生成两条边，同时考虑实际节点值和索引，而我期待它，只创建边缘节点唯一索引之间。请查看示例代码和下图。

示例代码：

from pygraphviz import *

word_link = []
A = AGraph(directed=True)
ind = 0
A.add_node(ind, color='lightskyblue', style='filled', label='Root', shape='box')
sen_ind = ind + 1
# sentence 1
A.add_node(sen_ind, color='lightcoral', style='filled', label=0, shape='box')
A.add_edge(ind, sen_ind, color='plum', style='filled')
word_ind = sen_ind + 1
# word 1
A.add_node(word_ind, color='lightsalmon', style='filled', shape='box', label=0)
word_link.append(word_ind)
A.add_edge(sen_ind, word_ind, color='plum', style='filled')
word_ind += 1
# word 2
A.add_node(word_ind, color='lightsalmon', style='filled', shape='box', label=1)
A.add_edge(sen_ind, word_ind, color='plum', style='filled')
sen_ind = word_ind + 1
# sentence 2
A.add_node(sen_ind, color='lightcoral', style='filled', label=1, shape='box')
A.add_edge(ind, sen_ind, color='plum', style='filled')
word_ind = sen_ind + 1
# word 1
A.add_node(word_ind, color='lightsalmon', style='filled', label=0, shape='box')
A.add_edge(sen_ind, word_ind, color='plum', style='filled')
word_ind += 1
# word 2
A.add_node(word_ind, color='lightsalmon', style='filled', label=1, shape='box')
word_link.append(word_ind)
A.add_edge(sen_ind, word_ind, color='plum', style='filled')

# doesn't work | need a fix
A.add_edge(word_link[0], word_link[1], color='sienna', style='filled')

A.layout()  # layout with default (neato)
A.draw('simple.png',prog='dot') # draw png

使用重复边生成的树

预期图：

Answer 1

尝试添加constraint=False：

A.add_edge(word_link[0], word_link[1], constraint=False, color='sienna', style='filled')

Answer 2

您还可以尝试定义排名（级别）

看到这个答案另一个用途给了我一个类似的问题：

Pygraphviz / networkx set node level or layer