pygraphviz 1.5默认边缘没有箭头?

问题描述

我在这里使用此转盘已将pygraphviz 1.5更新为在Windows 10 64位Python 3.6上安装pygraphviz.

I have updated to pygraphviz 1.5 using this wheel here Installing pygraphviz on Windows 10 64-bit, Python 3.6.

我遇到了问题.

import pygraphviz as pgv

G = pgv.AGraph()

G.add_node('a')
G.add_node('b')
G.add_edge('a', 'b')
g_string = G.string()

print(g_string)

给我

strict digraph {
    a -- b;
}

在先前版本1.3上运行的相同代码给了我

while the same code ran on previous version 1.3 gives me

strict digraph {
    a -> b;
}

我什至尝试过

G.add_edge('a', 'b', arrowhead="normal")给出a -- b [arrowhead=normal];，但没有箭头绘制.

G.add_edge('a', 'b', arrowhead="normal") which gives a -- b [arrowhead=normal]; but draws with no arrowheads.

我正在运行graphviz 2.38.python 2.7上的pygraphviz 1.3.pygraphviz 1.5在python 3.6上.

I'm running graphviz 2.38.pygraphviz 1.3 on python 2.7.pygraphviz 1.5 on python 3.6.

推荐答案

我首先要指出，为了使该示例正常工作，仅凭让 PyGraphviz不够 模块已安装(请检查 [SO]:在Windows 10 64位Python 3.6(@CristiFati的答案))上安装pygraphviz，但还需要 Graphviz 版本，以及 PyGraphviz 使用其工具之一(称为 nop ).
它可以下载，无论如何我选择构建它(对于 32bit ，但这无关紧要).

I want to start by pointing out that in order for this example to work, it's not enough to have the PyGraphviz module installed (check [SO]: Installing pygraphviz on Windows 10 64-bit, Python 3.6 (@CristiFati's answer)), but a version of Graphviz is required as well, as PyGraphviz uses one of its tools (called nop).
It is available for download, anyway I chose to build it (for 32bit, but that's not relevant).

我还用2个 .whl s进行了测试:

Also, I tested with 2 .whls:

• 一个(我为) Python 3.6 (64位)
构建的
• 一个为 Python 2.7 (64位)
构建的

• One (that I've) built for Python 3.6 (64 bit)
• One built for Python 2.7 (64 bit)

由于我有可能不得不修改它们(出于调试目的)，所以我没有pip install它们，而是将它们解压缩为 cwd (这需要一些额外的代码):

Since there was the possibility of me having to modify them (for debugging purposes), I didn't pip install them, but rather unpacked them in cwd (which required some extra code):

[cfati@CFATI-5510-0:e:\Work\Dev\StackOverflow\q055196206]> dir /b
code00.py
pygraphviz131_27
pygraphviz15_36

[cfati@CFATI-5510-0:e:\Work\Dev\StackOverflow\q055196206]> tree /a
Folder PATH listing for volume Work
Volume serial number is 3655-6FED
E:.
+---pygraphviz131_27
|   \---pygraphviz
|       \---tests
\---pygraphviz15_36
    \---pygraphviz
        \---tests

code00.py :

#!/usr/bin/env python3

import sys


# @TODO - cfati: The 5 lines below are because I unpacked the 2 `.whl`s in the current dir, instead of `pip install`ing them
maj, min = sys.version_info[:2]
if maj == 3 and min == 6:
    sys.path.insert(0, "pygraphviz15_36")
elif maj == 2 and min == 7:
    sys.path.insert(0, "pygraphviz131_27")
# @TODO end

import pygraphviz as pgv


def main():
    print(pgv)
    g = pgv.AGraph(directed=len(sys.argv) > 1)
    g.add_node("a")
    g.add_node("b")
    g.add_edge("a", "b")
    #print(dir(g))
    g_string = g.string()  # Nice var name, btw :)
    print(g_string)


if __name__ == "__main__":
    print("Python {:s} on {:s}\n".format(sys.version, sys.platform))
    main()

输出:

[cfati@CFATI-5510-0:e:\Work\Dev\StackOverflow\q055196206]> set PATH=%PATH%;e:\Work\Dev\Fati\WinBuild\graphviz\src\graphviz\Release\Graphviz\bin

[cfati@CFATI-5510-0:e:\Work\Dev\StackOverflow\q055196206]> "e:\Work\Dev\VEnvs\py_064_02.07.15_test0\Scripts\python.exe" code00.py
Python 2.7.15 (v2.7.15:ca079a3ea3, Apr 30 2018, 16:30:26) [MSC v.1500 64 bit (AMD64)] on win32

<module 'pygraphviz' from 'pygraphviz131_27\pygraphviz\__init__.pyc'>
strict digraph {
        a -> b;
}


[cfati@CFATI-5510-0:e:\Work\Dev\StackOverflow\q055196206]> "e:\Work\Dev\VEnvs\py_064_03.06.08_test0\Scripts\python.exe" code00.py
Python 3.6.8 (tags/v3.6.8:3c6b436a57, Dec 24 2018, 00:16:47) [MSC v.1916 64 bit (AMD64)] on win32

<module 'pygraphviz' from 'pygraphviz15_36\\pygraphviz\\__init__.py'>
strict graph "" {
        a -- b;
}

如图所示，该问题很容易重现.现在，输出 - vs. -> 我将如何表示无向 vs.有向图边.我查看了源代码，发现了一些奇怪的地方.

As seen, the problem is easily reproducible. Now, the outputs -- vs. -> look awfully a lot to how I'd represent an undirected vs. directed graph edge. I looked in the source code and found something strange.

[GitHub.PyGraphviz 1.5]:类 AGraph ( thing = None，filename = None，data = None，string = None，handle = None，name =''，strict = True，directed = False，** attr )具有directed=False arg.将其设置为 True 即可解决此问题.

[GitHub.PyGraphviz 1.5]: class AGraph(thing=None, filename=None, data=None, string=None, handle=None, name='', strict=True, directed=False, **attr) has the directed=False arg. Setting it to True, fixed the problem.

输出:

[cfati@CFATI-5510-0:e:\Work\Dev\StackOverflow\q055196206]> "e:\Work\Dev\VEnvs\py_064_02.07.15_test0\Scripts\python.exe" code00.py dummy_arg
Python 2.7.15 (v2.7.15:ca079a3ea3, Apr 30 2018, 16:30:26) [MSC v.1500 64 bit (AMD64)] on win32

<module 'pygraphviz' from 'pygraphviz131_27\pygraphviz\__init__.pyc'>
strict digraph {
        a -> b;
}


[cfati@CFATI-5510-0:e:\Work\Dev\StackOverflow\q055196206]> "e:\Work\Dev\VEnvs\py_064_03.06.08_test0\Scripts\python.exe" code00.py dummy_arg
Python 3.6.8 (tags/v3.6.8:3c6b436a57, Dec 24 2018, 00:16:47) [MSC v.1916 64 bit (AMD64)] on win32

<module 'pygraphviz' from 'pygraphviz15_36\\pygraphviz\\__init__.py'>
strict digraph "" {
        a -> b;
}

我说我发现了一件奇怪的事情:好吧，因为 PyGraphviz 1.3.1 事情是一样的: directed=False (代码和文档)，但它会以某种方式初始化图形，将其定向.
快速查看 agraph.py (在2个软件包版本中)并没有发现这种差异的来源，因此我可以放心地认为这是由于 Graphviz 包含2个 PyGraphviz 版本的软件包版本.

I said that I discovered something strange: well, for PyGraphviz 1.3.1 things are the same: directed=False (code and doc), yet it somehow initializes the graph as it would be directed.
A quick check on agraph.py (on the 2 package versions) didn't reveal where this difference comes from, so I can safely assume that it's because of Graphviz package versions that the 2 PyGraphviz versions were built with.

尽管如此， PyGraphviz 1.5 (由我构建)的行为是正确的.

Nevertheless, PyGraphviz 1.5 (built by me) behavior is the correct one.

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