问题描述
我试图在Colab上运行Pennylane，所以我先安装它。但是“已安装的设备”为空，这是怎么回事？我已经重新启动并重建了好几次。这是我的代码。
!pip install pennylane pennylane-qiskit
import pennylane as qml
qml.about()
这是结果（“已安装的设备”中没有任何内容）：
Successfully built qiskit python-constraint contextvars yfinance docplex dlx
Installing collected packages: semantic-version,appdirs,pennylane,sympy,fastjsonschema,retworkx,python-constraint,ply,immutables,contextvars,qiskit-terra,pybind11,qiskit-aer,websockets,cryptography,ntlm-auth,requests-ntlm,qiskit-ibmq-provider,qiskit-ignis,inflection,quandl,lxml,yfinance,docplex,dlx,qiskit-aqua,qiskit,pennylane-qiskit
Found existing installation: sympy 1.1.1
Uninstalling sympy-1.1.1:
Successfully uninstalled sympy-1.1.1
Found existing installation: lxml 4.2.6
Uninstalling lxml-4.2.6:
Successfully uninstalled lxml-4.2.6
Successfully installed appdirs-1.4.4 contextvars-2.4 cryptography-3.2.1 dlx-1.0.4 docplex-2.15.194 fastjsonschema-2.14.5 immutables-0.14 inflection-0.5.1 lxml-4.6.1 ntlm-auth-1.5.0 pennylane-0.12.0 pennylane-qiskit-0.12.0 ply-3.11 pybind11-2.6.0 python-constraint-1.4.0 qiskit-0.23.0 qiskit-aer-0.7.0 qiskit-aqua-0.8.0 qiskit-ibmq-provider-0.11.0 qiskit-ignis-0.5.0 qiskit-terra-0.16.0 quandl-3.5.3 requests-ntlm-1.1.0 retworkx-0.5.0 semantic-version-2.6.0 sympy-1.6.2 websockets-8.1 yfinance-0.1.55
Name: PennyLane
Version: 0.12.0
Summary: PennyLane is a Python quantum machine learning library by Xanadu Inc.
Home-page: https://github.com/XanaduAI/pennylane
Author: None
Author-email: None
License: Apache License 2.0
Location: /usr/local/lib/python3.6/dist-packages
Requires: semantic-version,scipy,autograd,networkx,numpy,toml
required-by: PennyLane-qiskit
Platform info: Linux-4.19.112+-x86_64-with-ubuntu-18.04-bionic
Python version: 3.6.9
Numpy version: 1.18.5
Scipy version: 1.4.1
Installed devices:
当我尝试使用设备时，我得到了
引发DeviceError（“设备不存在。请确保已安装所需的插件。”）