Not compatible with python 3.7

[vnnw]

Run the demo with Python 3.7 will raise a StopIteration exception, but works properly with Python 3.6.

In [1]: import dowhy
   ...: from dowhy.do_why import CausalModel
   ...: import dowhy.datasets
   ...:
   ...:

In [2]: data=dowhy.datasets.linear_dataset(
   ...:         beta=10,
   ...:         num_common_causes=5,
   ...:         num_instruments = 2,
   ...:         num_samples=10000,
   ...:         treatment_is_binary=True)
   ...:

In [3]: model=CausalModel(
   ...:         data = data["df"],
   ...:         treatment=data["treatment_name"],
   ...:         outcome=data["outcome_name"],
   ...:         graph=data["dot_graph"],
   ...:         )
   ...:
---------------------------------------------------------------------------
StopIteration                             Traceback (most recent call last)
~/anaconda3/envs/dowhy/lib/python3.7/site-packages/pygraphviz/agraph.py in iteritems(self)
   1749             try:
-> 1750                 ah = gv.agnxtattr(self.handle, self.type, ah)
   1751                 yield (gv.agattrname(ah).decode(self.encoding),

StopIteration: agnxtattr

The above exception was the direct cause of the following exception:

RuntimeError                              Traceback (most recent call last)
<ipython-input-3-e382d2368efa> in <module>()
      3         treatment=data["treatment_name"],
      4         outcome=data["outcome_name"],
----> 5         graph=data["dot_graph"],
      6         )
      7

~/Desktop/dowhy-master/dowhy/do_why.py in __init__(self, data, treatment, outcome, graph, common_causes, instruments, estimand_type, **kwargs)
     96                 self._outcome,
     97                 graph,
---> 98                 observed_node_names=self._data.columns.tolist()
     99             )
    100             self._common_causes = self._graph.get_common_causes(self._treatment, self._outcome)

~/Desktop/dowhy-master/dowhy/causal_graph.py in __init__(self, treatment_name, outcome_name, graph, common_cause_names, instrument_names, observed_node_names)
     26             self._graph = pgv.AGraph(graph, strict=True, directed=True)
     27
---> 28         self._graph = nx.drawing.nx_agraph.from_agraph(self._graph)
     29         self._graph = self.add_node_attributes(observed_node_names)
     30         self._graph = self.add_unobserved_common_cause(observed_node_names)

~/anaconda3/envs/dowhy/lib/python3.7/site-packages/networkx/drawing/nx_agraph.py in from_agraph(A, create_using)
     85
     86     # add graph attributes
---> 87     N.graph.update(A.graph_attr)
     88
     89     # add nodes, attributes to N.node_attr

~/anaconda3/envs/dowhy/lib/python3.7/site-packages/pygraphviz/agraph.py in keys(self)
   1738
   1739     def keys(self):
-> 1740         return list(self.__iter__())
   1741
   1742     def __iter__(self):

~/anaconda3/envs/dowhy/lib/python3.7/site-packages/pygraphviz/agraph.py in __iter__(self)
   1741
   1742     def __iter__(self):
-> 1743         for (k, v) in self.iteritems():
   1744             yield k
   1745

[amit-sharma]

Thanks for pointing this out.
DoWhy depends on Pygraphviz for visualization and unfortunately there seems to be a problem in Pygraphviz for Python 3.7. I'm considering moving away from this dependency, allow me a few days to fix this.

[cpoptic]

This issue applies also to Python 3.6.6 (on a Windows 10, 64 env). It appears to be a Pygraphviz installation issue.

[amit-sharma]

I removed the dependency on pygraphviz, making it optional. If pygraphviz is not installed, the library falls back to matplotlib and plots causal graph using it. @vnnw @cpoptic can you check if it works for you?

[cpoptic]

just did a git pull and pip install -U dowhy and I'm still getting the same result on Python 3.6

import dowhy works with no problems. But when I run from dowhy.do_why import Causal Model it get an error:

ModuleNotFoundError: No module named 'pygraphviz'

So it appears the dowhy package imports fine, but the do_why module is still dependent on pygraphviz.

[amit-sharma]

Thanks @cpoptic Not sure why it still shows an error. I did check with python 3.6 in a virtualenv and it worked.

Maybe an earlier install of dowhy is still being called? To make sure, can you try the following code which relies on the source distribution only (and does not use pip)?

[Run this code from the root directory of dowhy]
`import os, sys
sys.path.append(os.path.abspath("./"))
import numpy as np
import pandas as pd

import dowhy
from dowhy.do_why import CausalModel`

[impredicative]

Any formal update? Is 3.7 fully supported now?

[amit-sharma]

@impredicative Yes, it should work in 3.7. Let me know if you face any problems.

[akelleh]

@amit-sharma two weeks with no problem reported -- safe to close?

[amit-sharma]

yes, closing it now. @impredicative if you face any problems with 3.7, let us know.