Q: How should I cite Qiskit in my research?

A: Please cite Qiskit by using the included BibTeX file.

Q: Why do I receive the error message Error: Instance of QuantumCircuit has no member when adding gates to a circuit?

A: This is a pylint error, which is a Linter for Python. Linters analyze code for potential errors, and they throw errors when they find potentially erroneous code. However, this error should not prevent your code from compiling or running, so there is no need to worry. The error message can be disabled by adding the following line above the code that is causing the error:

#pylint: disable=no-member


Q: Why do my results from real devices differ from my results from the simulator?

A: The simulator runs jobs as though is was in an ideal environment; one without noise or decoherence. However, when jobs are run on the real devices there is noise from the environment and decoherence, which causes the qubits to behave differently than what is intended.

Q: Why do I receive the error message, No Module 'qiskit' when using Jupyter Notebook?

A: If you used pip install qiskit and set up your virtual environment in Anaconda, then you may experience this error when you run a tutorial in Jupyter Notebook. If you have not installed Qiskit or set up your virtual environment, you can follow the installation steps.

The error is caused when trying to import the Qiskit package in an environment where Qiskit is not installed. If you launched Jupyter Notebook from the Anaconda-Navigator, it is possible that Jupyter Notebook is running in the base (root) environment, instead of in your virtual environment. Choose a virtual environment in the Anaconda-Navigator from the Applications on dropdown menu. In this menu, you can see all of the virtual environments within Anaconda, and you can select the environment where you have Qiskit installed to launch Jupyter Notebook.

Q: Why am I getting a compilation error while installing qiskit?

A: Qiskit depends on a number of other open source Python packages, which are automatically installed when doing pip install qiskit. Depending on your system’s platform and Python version, is it possible that a particular package does not provide a pre-built binary wheel for your system, and in those cases pip will attempt to compile the package from source, which in turn might require some extra dependencies that need to be installed manually.

If the output of pip install qiskit contains similar lines to:

Failed building wheel for SOME_PACKAGE
...
build/temp.linux-x86_64-3.5/_openssl.c:498:30: fatal error
compilation terminated.
error: command 'x86_64-linux-gnu-gcc' failed with exit status 1


please check the documentation of the package that failed to install (in the example code, SOME_PACKAGE) for information on how to install the libraries needed for compiling from source. For example: