How can I run kerberos sampler on 2000Q?

• 

  David J  (Report)

  November 10, 2021 23:34 (Edited November 13, 2021 00:12)

  Hello,

  You can provide the KerberosSampler with a DWaveSampler that uses Feature-Based Solver Selection in the sample() function call like this:

  from dwave.system import DWaveSampler
  from hybrid import KerberosSampler
  sampler = KerberosSampler()
  sampleset = sampler.sample(bqm, qpu_sampler=DWaveSampler(solver=dict(topology__type='pegasus')))
  #OR
  sampleset = sampler.sample(bqm, qpu_sampler=DWaveSampler(solver=dict(topology__type='chimera')))

  Check out the docs to see the variables that can be provided to the functions and the constructors here:
  https://docs.ocean.dwavesys.com/projects/hybrid/en/stable/reference/reference.html

  Hopefully this helps with what you need.
  Please feel free to reach out if you have more questions.

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• 

  Giuliana S  (Report)

  November 11, 2021 10:15

  Thank you very much, David.

  I applied the solution you suggested for Kerberos and it worked.

  I tried to do the same with the LeapHybridSampler and I am stuck in a new problem. If I do

  sampler = LeapHybridSampler()
  solution = sampler.sample(bqm, qpu_sampler=DWaveSampler(solver=dict(topology__type='chimera'), ), label='Example - Hybrid on chimera', )

  when I try to get the solution
  best_solution = solution.first.sample

  I get this error.

  File "/home/ljulie/anaconda3/envs/dwave/lib/python3.7/site-packages/dimod/sampleset.py", line 832, in first
  return next(self.data(sorted_by='energy', name='Sample'))
  File "/home/ljulie/anaconda3/envs/dwave/lib/python3.7/site-packages/dimod/sampleset.py", line 1039, in data
  record = self.record
  File "/home/ljulie/anaconda3/envs/dwave/lib/python3.7/site-packages/dimod/sampleset.py", line 873, in record
  self.resolve()
  File "/home/ljulie/anaconda3/envs/dwave/lib/python3.7/site-packages/dimod/sampleset.py", line 1208, in resolve
  samples = self._result_hook(self._future)
  File "/home/ljulie/anaconda3/envs/dwave/lib/python3.7/site-packages/dwave/cloud/computation.py", line 836, in <lambda>
  self, lambda f: f.wait_sampleset())
  File "/home/ljulie/anaconda3/envs/dwave/lib/python3.7/site-packages/dwave/cloud/computation.py", line 776, in wait_sampleset
  result = self._load_result()
  File "/home/ljulie/anaconda3/envs/dwave/lib/python3.7/site-packages/dwave/cloud/computation.py", line 901, in _load_result
  raise self._exception
  File "/home/ljulie/anaconda3/envs/dwave/lib/python3.7/concurrent/futures/thread.py", line 57, in run
  result = self.fn(*self.args, **self.kwargs)
  File "/home/ljulie/anaconda3/envs/dwave/lib/python3.7/site-packages/dwave/cloud/solver.py", line 402, in _encode_problem_for_submission
  body_data = json.dumps(body)
  File "/home/ljulie/anaconda3/envs/dwave/lib/python3.7/json/__init__.py", line 231, in dumps
  return _default_encoder.encode(obj)
  File "/home/ljulie/anaconda3/envs/dwave/lib/python3.7/json/encoder.py", line 199, in encode
  chunks = self.iterencode(o, _one_shot=True)
  File "/home/ljulie/anaconda3/envs/dwave/lib/python3.7/json/encoder.py", line 257, in iterencode
  return _iterencode(o, 0)
  File "/home/ljulie/anaconda3/envs/dwave/lib/python3.7/json/encoder.py", line 179, in default
  raise TypeError(f'Object of type {o.__class__.__name__} '
  TypeError: Object of type DWaveSampler is not JSON serializable

  what am I doing wrong? Thank you in advance.

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• 

  David J  (Report)

  November 13, 2021 00:40

  Hello,

  I had to make a correction about the Kerberos object. It is possible to use, but it's a bit more complicated than I had originally stated, so I have removed the example for now. You can take a look at the implication of KerberosSampler for a better idea of how to use it this way if desired.

  For the above error that you are seeing, you will need to move your DWaveSampler construction to the LeapHybridSampler constructor, like this:

  sampler = LeapHybridSampler(sampler=DWaveSampler(solver=dict(topology__type='chimera')))
  solution = sampler.sample(bqm, label='Example - Hybrid on chimera')

  Hopefully this helps you get back to development.
  Please feel free to let us know if you have any other questions.
  If the nature of the question changes like this one in that it no longer matches the title of the original request, we kindly ask that you start a new thread so that it is easier to search for and reference in the future.

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