QInfer/python-qinfer

Truth value of an array with more than one element is ambiguous.

Closed this issue · 3 comments

Nowzerix commented

Hi all, I'm getting an error with qinfer that I don't know what to do with. Sometimes this gets thrown, sometimes not. I was wondering if someone could have a look at it. I am using the TomographyModel with my own heuristic.

Traceback (most recent call last):
  File "qinfer_test.py", line 69, in <module>
    tally[detect(true_state)] += 1
  File "qinfer_test.py", line 58, in detect
    updater.update(data, experiment)
  File "/home/jayce/.local/lib/python3.5/site-packages/qinfer/smc.py", line 425, in update
    weights, norm = self.hypothetical_update(outcome, expparams, return_normalization=True)
  File "/home/jayce/.local/lib/python3.5/site-packages/qinfer/smc.py", line 365, in hypothetical_update
    L = self.model.likelihood(outcomes, locs, expparams).transpose([0, 2, 1])
  File "/home/jayce/.local/lib/python3.5/site-packages/qinfer/tomography/models.py", line 217, in likelihood
    return FiniteOutcomeModel.pr0_to_likelihood_array(outcomes, 1 - pr1)
  File "/home/jayce/.local/lib/python3.5/site-packages/qinfer/abstract_model.py", line 675, in pr0_to_likelihood_array
    for idx in range(safe_shape(outcomes))
  File "/home/jayce/.local/lib/python3.5/site-packages/qinfer/abstract_model.py", line 675, in <listcomp>
    for idx in range(safe_shape(outcomes))
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()
ihincks commented

After a quick look, I think the problem is possibly that your variable data is more than 1-dimensional when this error is thrown, which is not supported (ie np.ndim(data) should be less than 2).

This is happening on line 674 of abstract_model.pywhen it is checking which measurement outcomes are 0, and which are 1, which gives the same error as follows:

a=np.array([[0,1],[0,1]])
if a[0] == 0:
    pass
ihincks commented

(If this doesn't fix the problem, we might need some example code that raises this error)

Nowzerix commented

Alright, caught the bug in my code. It's so much easier when I know what I'm looking for. Thanks a bunch.

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