AssertionError with self-loops from Python but not from command line

[RochMoreau]

The code given in the README is issuing a AssertionError: Predicted link (981, 981) is a self-loop!, but the terminal command with the exact same training file is doing the job.

---------------------------------------------------------------------------
AssertionError                            Traceback (most recent call last)
 in 
      7 
      8 simrank = linkpred.predictors.SimRank(training, excluded=training.edges())
----> 9 simrank_results = simrank.predict(c=0.5)
     10 
     11 evaluation = linkpred.evaluation.EvaluationSheet(simrank_results, test.edges())

~/anaconda3/envs/social-media/lib/python3.7/site-packages/linkpred/predictors/base.py in predict_and_postprocess(*args, **kwargs)
     65                 for u, v in self.excluded:
     66                     try:
---> 67                         del scoresheet[(u, v)]
     68                     except KeyError:
     69                         pass

~/anaconda3/envs/social-media/lib/python3.7/site-packages/linkpred/evaluation/scoresheet.py in __delitem__(self, key)
    193 
    194     def __delitem__(self, key):
--> 195         return dict.__delitem__(self, Pair(key))
    196 
    197     def process_data(self, data, weight='weight'):

~/anaconda3/envs/social-media/lib/python3.7/site-packages/linkpred/evaluation/scoresheet.py in __init__(self, *args)
    125                 "__init__() takes 1 or 2 arguments in addition to self")
    126         # For link prediction, a and b are two different nodes
--> 127         assert a != b, "Predicted link (%s, %s) is a self-loop!" % (a, b)
    128         self.elements = self._sorted_tuple((a, b))
    129 

AssertionError: Predicted link (381, 381) is a self-loop!
>>>

​

[rafguns]

Thanks for the report. Very strange, I'll have to investigate more...

[RochMoreau]

Thanks for the fast response !
Keep me posted please, I am very interested by this project.
I can provide some more informations if you need (output of terminal command)

[RochMoreau]

Got it working by removing self-loop edges before calling the predictor. The accuracy is not good though but I don't have any comparison point so I can't say if the bad accuracy is a consequence of this fix.

Here is the code:

G = linkpred.read_network("training.net")

# This line is the fix to avoid the AssertionError
G.remove_edges_from(G.selfloop_edges())

test = G.subgraph(random.sample(G.nodes(), 300))

# Exclude test network from learning phase
training = G.copy()
training.remove_edges_from(test.edges())

simrank = linkpred.predictors.SimRank(training, excluded=training.edges())
simrank_results = simrank.predict(c=0.5)

evaluation = linkpred.evaluation.EvaluationSheet(simrank_results, test.edges())

plt.plot(evaluation.recall(), evaluation.precision())

[rafguns]

Ah, this is the code I gave as an example in #18, right? If your data contains self-loops, you should indeed remove them. If you call linkpred from the command-line, it will do something similar.

Low accuracy indicates that this predictor does not work well on your data but has nothing to do with the self-loops. You may want to try experimenting with a few of the other predictors to see if they give better results.

[rafguns]

I think this can be closed, but please reopen if there is still an issue here relating to the self-loops. Thanks!