[BUG] AttributeError: 'float' object has no attribute 'ndim' when using qml.RX/qml.RY

[salcc]

Expected behavior

It works without error, like in the documentation: https://pennylane.ai/qml/demos/tutorial_qubit_rotation.html.

Actual behavior

It produces an error (AttributeError: 'float' object has no attribute 'ndim').

Additional information

To reproduce the error, I used a minimal clean Conda environment created with the following commands:

conda create --name bugreport python=3.10
conda activate bugreport
pip install pennylane

Source code

import pennylane as qml
from pennylane import numpy as np

dev1 = qml.device("default.qubit", wires=1)

@qml.qnode(dev1, interface="autograd")
def circuit(params):
    qml.RX(params[0], wires=0)
    qml.RY(params[1], wires=0)
    return qml.expval(qml.PauliZ(0))

print(circuit([0.54, 0.12]))

Tracebacks

Traceback (most recent call last):
  File "/home/salcc/Documents/bugreport/main.py", line 12, in <module>
    print(circuit([0.54, 0.12]))
  File "/home/salcc/miniconda3/envs/bugreport/lib/python3.10/site-packages/pennylane/qnode.py", line 842, in __call__
    self.construct(args, kwargs)
  File "/home/salcc/miniconda3/envs/bugreport/lib/python3.10/site-packages/pennylane/qnode.py", line 751, in construct
    self._tape = make_qscript(self.func)(*args, **kwargs)
  File "/home/salcc/miniconda3/envs/bugreport/lib/python3.10/site-packages/pennylane/tape/qscript.py", line 1371, in wrapper
    result = fn(*args, **kwargs)
  File "/home/salcc/Documents/bugreport/main.py", line 9, in circuit
    qml.RY(params[1], wires=0)
  File "/home/salcc/miniconda3/envs/bugreport/lib/python3.10/site-packages/pennylane/ops/qubit/parametric_ops.py", line 182, in __init__
    super().__init__(phi, wires=wires, do_queue=do_queue, id=id)
  File "/home/salcc/miniconda3/envs/bugreport/lib/python3.10/site-packages/pennylane/operation.py", line 1627, in __init__
    super().__init__(*params, wires=wires, do_queue=do_queue, id=id)
  File "/home/salcc/miniconda3/envs/bugreport/lib/python3.10/site-packages/pennylane/operation.py", line 1005, in __init__
    self._check_batching(params)
  File "/home/salcc/miniconda3/envs/bugreport/lib/python3.10/site-packages/pennylane/operation.py", line 1025, in _check_batching
    ndims = tuple(qml.math.ndim(p) for p in params)
  File "/home/salcc/miniconda3/envs/bugreport/lib/python3.10/site-packages/pennylane/operation.py", line 1025, in <genexpr>
    ndims = tuple(qml.math.ndim(p) for p in params)
  File "/home/salcc/miniconda3/envs/bugreport/lib/python3.10/site-packages/autoray/autoray.py", line 79, in do
    return get_lib_fn(backend, fn)(*args, **kwargs)
  File "/home/salcc/miniconda3/envs/bugreport/lib/python3.10/site-packages/autoray/autoray.py", line 886, in ndim
    return x.ndim
AttributeError: 'float' object has no attribute 'ndim'

System information

Name: PennyLane
Version: 0.29.0
Summary: PennyLane is a Python quantum machine learning library by Xanadu Inc.
Home-page: https://github.com/XanaduAI/pennylane
Author: 
Author-email: 
License: Apache License 2.0
Location: /home/salcc/miniconda3/envs/bugreport/lib/python3.10/site-packages
Requires: appdirs, autograd, autoray, cachetools, networkx, numpy, pennylane-lightning, requests, retworkx, scipy, semantic-version, toml
Required-by: PennyLane-Lightning

Platform info:           Linux-5.19.0-32-generic-x86_64-with-glibc2.35
Python version:          3.10.9
Numpy version:           1.23.5
Scipy version:           1.10.1
Installed devices:
- lightning.qubit (PennyLane-Lightning-0.29.0)
- default.gaussian (PennyLane-0.29.0)
- default.mixed (PennyLane-0.29.0)
- default.qubit (PennyLane-0.29.0)
- default.qubit.autograd (PennyLane-0.29.0)
- default.qubit.jax (PennyLane-0.29.0)
- default.qubit.tf (PennyLane-0.29.0)
- default.qubit.torch (PennyLane-0.29.0)
- default.qutrit (PennyLane-0.29.0)
- null.qubit (PennyLane-0.29.0)

Existing GitHub issues

• I have searched existing GitHub issues to make sure the issue does not already exist.

[salcc]

I tried installing previous versions of PennyLane, and it gives me the same error for all the versions down to 0.24. PennyLane 0.23 does not produce the error and works as expected.

[josh146]

Hi @salcc! Unfortunately, this is due to a new version of autoray, which was released this week, which is incompatible with PennyLane 0.29.

We're currently working on a bugfix - in the meantime, if you downgrade autoray,

pip install autoray==0.6.0

this should allow PennyLane v0.29 to work.

[a-o-can]

@salcc @josh146
It also works if you pass in a numpy array as such:

print(circuit(np.array([0.54, 0.12])))

[trbromley]

We have now released a bugfix 0.29.1 version of PennyLane that fixes this issue. Please run:

pip install -U pennylane

[jcmgray]

Hello I'm the main developer of autoray - just stumbled across this issue by chance and wasn't aware of the regression, sorry about that:

1. it should be fixed in https://github.com/jcmgray/autoray/releases/tag/v0.6.3
2. thought I'd also encourage any developers here to upstream any issues and also extra functionality to autoray, if you want!