# AttributeError: 'Adjoint' object has no attribute 'supports\_heisenberg'
**URL:** https://discuss.pennylane.ai/t/attributeerror-adjoint-object-has-no-attribute-supports-heisenberg/4210
**Category:** PennyLane Help
**Created:** [March 2, 2024, 11:26am UTC](https://discuss.pennylane.ai/t/attributeerror-adjoint-object-has-no-attribute-supports-heisenberg/4210 "2024-03-02T11:26:22Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@RX1](https://discuss.pennylane.ai/u/RX1)
#### Post date: [March 2, 2024, 11:26am UTC](https://discuss.pennylane.ai/t/attributeerror-adjoint-object-has-no-attribute-supports-heisenberg/4210/1 "2024-03-02T11:26:22Z")
```auto
def DataEncoding(data, wires_start, wires_end):
qml.Squeezing(data[0], data[1], wires=wires_start)
qml.Squeezing(data[2], data[3], wires=wires_end)
qml.Kerr(data[4], wires=wires_start)
qml.Kerr(data[5], wires=wires_end)
qml.Rotation(data[6], wires=wires_start)
qml.Rotation(data[7], wires=wires_end)
qml.Beamsplitter(data[8], data[9],wires=[wires_start, wires_end])
I used the following code:
qml.adjoint(DataEncoding)(x2, 0, 1)
```
```auto
--------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
Cell In[9], line 1
----> 1 his_acc_val, his_acc_train, his_cost = TrainAdam(params_init)
2 print(his_acc_val, his_acc_train, his_cost)
Cell In[8], line 13, in TrainAdam(params_init)
11 feats_train_batch = feats_train[batch_index]
12 Y_train_batch = Y_train[batch_index]
---> 13 (weights, _, _), _cost = opt.step_and_cost(cost, weights, feats_train_batch, Y_train_batch)
14 predictions_train = [np.sign(variational_classifier(weights, feat)) for feat in feats_train]
15 predictions_val = [np.sign(variational_classifier(weights, feat)) for feat in feats_val]
File d:\miniconda3\lib\site-packages\pennylane\optimize\gradient_descent.py:59, in GradientDescentOptimizer.step_and_cost(self, objective_fn, grad_fn, *args, **kwargs)
39 def step_and_cost(self, objective_fn, *args, grad_fn=None, **kwargs):
40 """Update trainable arguments with one step of the optimizer and return the corresponding
41 objective function value prior to the step.
42
(...)
56 If single arg is provided, list [array] is replaced by array.
57 """
---> 59 g, forward = self.compute_grad(objective_fn, args, kwargs, grad_fn=grad_fn)
60 new_args = self.apply_grad(g, args)
62 if forward is None:
File d:\miniconda3\lib\site-packages\pennylane\optimize\gradient_descent.py:117, in GradientDescentOptimizer.compute_grad(objective_fn, args, kwargs, grad_fn)
99 r"""Compute gradient of the objective function at the given point and return it along with
100 the objective function forward pass (if available).
101
(...)
114 will not be evaluted and instead ``None`` will be returned.
115 """
116 g = get_gradient(objective_fn) if grad_fn is None else grad_fn
--> 117 grad = g(*args, **kwargs)
118 forward = getattr(g, "forward", None)
120 num_trainable_args = sum(getattr(arg, "requires_grad", False) for arg in args)
File d:\miniconda3\lib\site-packages\pennylane\_grad.py:115, in grad. __call__ (self, *args, **kwargs)
112 self._forward = self._fun(*args, **kwargs)
113 return ()
--> 115 grad_value, ans = grad_fn(*args, **kwargs)
116 self._forward = ans
118 return grad_value
File d:\miniconda3\lib\site-packages\autograd\wrap_util.py:20, in unary_to_nary..nary_operator..nary_f(*args, **kwargs)
18 else:
19 x = tuple(args[i] for i in argnum)
---> 20 return unary_operator(unary_f, x, *nary_op_args, **nary_op_kwargs)
File d:\miniconda3\lib\site-packages\pennylane\_grad.py:141, in grad._grad_with_forward(fun, x)
135 if not vspace(ans).size == 1:
136 raise TypeError(
137 "Grad only applies to real scalar-output functions. "
138 "Try jacobian, elementwise_grad or holomorphic_grad."
139 )
--> 141 grad_value = vjp(vspace(ans).ones())
142 return grad_value, ans
File d:\miniconda3\lib\site-packages\autograd\core.py:14, in make_vjp..vjp(g)
---> 14 def vjp(g): return backward_pass(g, end_node)
File d:\miniconda3\lib\site-packages\autograd\core.py:21, in backward_pass(g, end_node)
19 for node in toposort(end_node):
20 outgrad = outgrads.pop(node)
---> 21 ingrads = node.vjp(outgrad[0])
22 for parent, ingrad in zip(node.parents, ingrads):
23 outgrads[parent] = add_outgrads(outgrads.get(parent), ingrad)
File d:\miniconda3\lib\site-packages\autograd\core.py:67, in defvjp..vjp_argnums..(g)
64 raise NotImplementedError(
65 "VJP of {} wrt argnum 0 not defined".format(fun. __name__ ))
66 vjp = vjpfun(ans, *args, **kwargs)
---> 67 return lambda g: (vjp(g),)
68 elif L == 2:
69 argnum_0, argnum_1 = argnums
File d:\miniconda3\lib\site-packages\pennylane\interfaces\autograd.py:228, in vjp..grad_fn(dy)
226 if _n == max_diff:
227 with qml.tape.Unwrap(*tapes):
--> 228 vjp_tapes, processing_fn = qml.gradients.batch_vjp(
229 tapes,
230 dy,
231 gradient_fn,
232 reduction="append",
233 gradient_kwargs=gradient_kwargs,
234 )
236 vjps = processing_fn(execute_fn(vjp_tapes)[0])
238 else:
File d:\miniconda3\lib\site-packages\pennylane\gradients\vjp.py:525, in batch_vjp(tapes, dys, gradient_fn, shots, reduction, gradient_kwargs)
523 # Loop through the tapes and dys vector
524 for tape, dy in zip(tapes, dys):
--> 525 g_tapes, fn = vjp(tape, dy, gradient_fn, shots=shots, gradient_kwargs=gradient_kwargs)
526 reshape_info.append(len(g_tapes))
527 processing_fns.append(fn)
File d:\miniconda3\lib\site-packages\pennylane\gradients\vjp.py:381, in vjp(tape, dy, gradient_fn, shots, gradient_kwargs)
378 except (AttributeError, TypeError, NotImplementedError):
379 pass
--> 381 gradient_tapes, fn = gradient_fn(tape, shots=shots, **gradient_kwargs)
383 def processing_fn(results, num=None):
384 # postprocess results to compute the Jacobian
385 jac = fn(results)
File d:\miniconda3\lib\site-packages\pennylane\transforms\batch_transform.py:340, in batch_transform. __call__ (self, *targs, **tkwargs)
335 return self._device_wrapper(*targs, **tkwargs)(qnode)
337 if isinstance(qnode, qml.tape.QuantumScript):
338 # Input is a quantum tape.
339 # tapes, fn = some_transform(tape, *transform_args)
--> 340 return self._tape_wrapper(*targs, **tkwargs)(qnode)
342 if isinstance(qnode, (qml.QNode, qml.ExpvalCost)):
343 # Input is a QNode:
344 # result = some_transform(qnode, *transform_args)(*qnode_args)
345 wrapper = self.qnode_wrapper(qnode, targs, tkwargs)
File d:\miniconda3\lib\site-packages\pennylane\transforms\batch_transform.py:430, in batch_transform._tape_wrapper..(tape)
429 def _tape_wrapper(self, *targs, **tkwargs):
--> 430 return lambda tape: self.construct(tape, *targs, **tkwargs)
File d:\miniconda3\lib\site-packages\pennylane\transforms\batch_transform.py:412, in batch_transform.construct(self, tape, *args, **kwargs)
409 if expand and self.expand_fn is not None:
410 tape = self.expand_fn(tape, *args, **kwargs)
--> 412 tapes, processing_fn = self.transform_fn(tape, *args, **kwargs)
414 if processing_fn is None:
416 def processing_fn(x):
File d:\miniconda3\lib\site-packages\pennylane\gradients\parameter_shift_cv.py:661, in param_shift_cv(tape, dev, argnum, shifts, gradient_recipes, fallback_fn, f0, force_order2, shots)
656 if any(isinstance(m, StateMP) for m in tape.measurements):
657 raise ValueError(
658 "Computing the gradient of circuits that return the state is not supported."
659 )
--> 661 _gradient_analysis_cv(tape)
663 if argnum is None and not tape.trainable_params:
664 warnings.warn(
665 "Attempted to compute the gradient of a tape with no trainable parameters. "
666 "If this is unintended, please mark trainable parameters in accordance with the "
667 "chosen auto differentiation framework, or via the 'tape.trainable_params' property."
668 )
File d:\miniconda3\lib\site-packages\pennylane\gradients\parameter_shift_cv.py:128, in _gradient_analysis_cv(tape)
125 tape._gradient_fn = param_shift_cv
127 for idx, info in enumerate(tape._par_info):
--> 128 info["grad_method"] = _grad_method(tape, idx)
File d:\miniconda3\lib\site-packages\pennylane\gradients\parameter_shift_cv.py:81, in _grad_method(tape, idx)
77 # For parameter-shift compatible CV gates, we need to check both the
78 # intervening gates, and the type of the observable.
79 best_method = "A"
---> 81 if any(not k.supports_heisenberg for k in ops_between):
82 # non-Gaussian operators present in-between the operation
83 # and the observable. Must fallback to numeric differentiation.
84 best_method = "F"
86 elif m.obs.ev_order == 2:
File d:\miniconda3\lib\site-packages\pennylane\gradients\parameter_shift_cv.py:81, in (.0)
77 # For parameter-shift compatible CV gates, we need to check both the
78 # intervening gates, and the type of the observable.
79 best_method = "A"
---> 81 if any(not k.supports_heisenberg for k in ops_between):
82 # non-Gaussian operators present in-between the operation
83 # and the observable. Must fallback to numeric differentiation.
84 best_method = "F"
86 elif m.obs.ev_order == 2:
AttributeError: 'Adjoint' object has no attribute 'supports_heisenberg'
```
---
### Author:  [@isaacdevlugt](https://discuss.pennylane.ai/u/isaacdevlugt)
#### Post date: [March 6, 2024, 11:02pm UTC](https://discuss.pennylane.ai/t/attributeerror-adjoint-object-has-no-attribute-supports-heisenberg/4210/2 "2024-03-06T23:02:21Z")
Hey @RX1,
Your code example is incomplete, so I’m not sure where the error is stemming from. Based on your traceback, it’s coming from here:
```auto
File d:\miniconda3\lib\site-packages\pennylane\gradients\parameter_shift_cv.py:81, in _grad_method(tape, idx)
77 # For parameter-shift compatible CV gates, we need to check both the
78 # intervening gates, and the type of the observable.
79 best_method = "A"
---> 81 if any(not k.supports_heisenberg for k in ops_between):
82 # non-Gaussian operators present in-between the operation
83 # and the observable. Must fallback to numeric differentiation.
84 best_method = "F"
86 elif m.obs.ev_order == 2:
```
Whatever `k` is, it doesn’t have a `supports_heisenberg` attribute. Here’s a searched list of operators that have such an attribute: [Search — PennyLane 0.35.0 documentation](https://docs.pennylane.ai/en/stable/search.html?q=supports_heisenberg&check_keywords=yes&area=default)
Let me know if that helps!