Describe the bug
qml.sample() throws error when run on SV1 simulator . The task is however executed on aws simulator and generates the json.
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-204-05637f991537> in <module>
4 qml.Hadamard(wires=1)
5 return qml.sample()
----> 6 circuit()
~/anaconda3/envs/Braket/lib/python3.7/site-packages/pennylane/qnode.py in __call__(self, *args, **kwargs)
583 gradient_kwargs=self.gradient_kwargs,
584 override_shots=override_shots,
--> 585 **self.execute_kwargs,
586 )
587
~/anaconda3/envs/Braket/lib/python3.7/site-packages/pennylane/interfaces/batch/__init__.py in execute(tapes, device, gradient_fn, interface, mode, gradient_kwargs, cache, cachesize, max_diff, override_shots, expand_fn, max_expansion, device_batch_transform)
411
412 res = _execute(
--> 413 tapes, device, execute_fn, gradient_fn, gradient_kwargs, _n=1, max_diff=max_diff, mode=_mode
414 )
415
~/anaconda3/envs/Braket/lib/python3.7/site-packages/pennylane/interfaces/batch/autograd.py in execute(tapes, device, execute_fn, gradient_fn, gradient_kwargs, _n, max_diff, mode)
70 gradient_kwargs=gradient_kwargs,
71 _n=_n,
---> 72 max_diff=max_diff,
73 )[0]
74
~/anaconda3/envs/Braket/lib/python3.7/site-packages/autograd/tracer.py in f_wrapped(*args, **kwargs)
46 return new_box(ans, trace, node)
47 else:
---> 48 return f_raw(*args, **kwargs)
49 f_wrapped.fun = f_raw
50 f_wrapped._is_autograd_primitive = True
~/anaconda3/envs/Braket/lib/python3.7/site-packages/pennylane/interfaces/batch/autograd.py in _execute(parameters, tapes, device, execute_fn, gradient_fn, gradient_kwargs, _n, max_diff)
106 """
107 with qml.tape.Unwrap(*tapes):
--> 108 res, jacs = execute_fn(tapes, **gradient_kwargs)
109
110 for i, r in enumerate(res):
~/anaconda3/envs/Braket/lib/python3.7/site-packages/pennylane/interfaces/batch/__init__.py in wrapper(tapes, **kwargs)
171 else:
172 # execute all unique tapes that do not exist in the cache
--> 173 res = fn(execution_tapes.values(), **kwargs)
174
175 final_res = []
~/anaconda3/envs/Braket/lib/python3.7/site-packages/pennylane/interfaces/batch/__init__.py in fn(tapes, **kwargs)
123 def fn(tapes, **kwargs): # pylint: disable=function-redefined
124 tapes = [expand_fn(tape) for tape in tapes]
--> 125 return original_fn(tapes, **kwargs)
126
127 @wraps(fn)
~/anaconda3/envs/Braket/lib/python3.7/contextlib.py in inner(*args, **kwds)
72 def inner(*args, **kwds):
73 with self._recreate_cm():
---> 74 return func(*args, **kwds)
75 return inner
76
~/anaconda3/envs/Braket/lib/python3.7/site-packages/braket/pennylane_plugin/braket_device.py in batch_execute(self, circuits, **run_kwargs)
359 def batch_execute(self, circuits, **run_kwargs):
360 if not self._parallel:
--> 361 return super().batch_execute(circuits)
362
363 for circuit in circuits:
~/anaconda3/envs/Braket/lib/python3.7/site-packages/pennylane/_qubit_device.py in batch_execute(self, circuits)
287 self.reset()
288
--> 289 res = self.execute(circuit)
290 results.append(res)
291
~/anaconda3/envs/Braket/lib/python3.7/site-packages/braket/pennylane_plugin/braket_device.py in execute(self, circuit, **run_kwargs)
218 def execute(self, circuit: CircuitGraph, **run_kwargs) -> np.ndarray:
219 self.check_validity(circuit.operations, circuit.observables)
--> 220 self._circuit = self._pl_to_braket_circuit(circuit, **run_kwargs)
221 self._task = self._run_task(self._circuit)
222 braket_result = self._task.result()
~/anaconda3/envs/Braket/lib/python3.7/site-packages/braket/pennylane_plugin/braket_device.py in _pl_to_braket_circuit(self, circuit, **run_kwargs)
151 for observable in circuit.observables:
152 dev_wires = self.map_wires(observable.wires).tolist()
--> 153 translated = translate_result_type(observable, dev_wires, self._braket_result_types)
154 if isinstance(translated, tuple):
155 for result_type in translated:
~/anaconda3/envs/Braket/lib/python3.7/site-packages/braket/pennylane_plugin/translation.py in translate_result_type(observable, targets, supported_result_types)
353 raise NotImplementedError(f"Return type {return_type} unsupported for Hamiltonian")
354
--> 355 braket_observable = _translate_observable(observable)
356 if return_type is ObservableReturnTypes.Expectation:
357 return Expectation(braket_observable, targets)
~/anaconda3/envs/Braket/lib/python3.7/functools.py in wrapper(*args, **kw)
838 '1 positional argument')
839
--> 840 return dispatch(args[0].__class__)(*args, **kw)
841
842 funcname = getattr(func, '__name__', 'singledispatch function')
~/anaconda3/envs/Braket/lib/python3.7/site-packages/braket/pennylane_plugin/translation.py in _translate_observable(observable)
366 @singledispatch
367 def _translate_observable(observable):
--> 368 raise TypeError(f"Unsupported observable: {observable}")
369
370
TypeError: Unsupported observable: sample(wires=[])
To reproduce
arn = "arn:aws:braket:::device/quantum-simulator/amazon/sv1"
dev = qml.device("braket.aws.qubit",device_arn=arn, wires=2,shots=1024)
@qml.qnode(dev)
def circuit():
qml.PauliX(wires=0)
qml.Hadamard(wires=1)
return qml.sample()
circuit()
Expected behavior
Should return tensors containing samples.
tensor([[1, 0, 0, 0, 0, 0],
[1, 1, 0, 0, 0, 0],
[1, 0, 0, 0, 0, 0],
…,
[1, 0, 0, 0, 0, 0],
[1, 1, 0, 0, 0, 0],
[1, 0, 0, 0, 0, 0]], requires_grad=True)
Screenshots or logs
If applicable, add screenshots or logs to help explain your problem.
System information
A description of your system. Please provide:
- Amazon Braket Python PennyLane Plugin version :
- 1.6.5
- Amazon Braket Python SDK version :
- 1.24.0
- Amazon Braket Python Schemas version :
- 1.8.0.dev0
- Amazon Braket Python Default Simulator version :
- 1.3.0
- Python version : 3.7
Additional context