Common Problems

On this page you will find answers and fixes to commonly known problems when dealing with our framework.

Installation

Externally-managed-environment

Error-Message

error: externally-managed-environment
× This environment is externally managed
....

Prerequisites

Running pip install .

Solution

This error happens on new python versions. In order to fix this, create a new virtual environment, activate it and re-run the command. Details about this topic can be found under the name PEP 668. The following is an example of initializing a simple venv:

python -m venv .venv
source .venv/bin/activate
pip install .

Another solution (which we do not recommend but will work) is adding the --break-system-packages-flag and running again:

pip install . --break-system-packages

Warning

If you choose to break the system packages and enforce the installation, you might break your python-environment! Please only consider this option if you know what you are doing!

Runtime

ModuleNotFoundError: PySAT

Error-Message

ModuleNotFoundError: No module named 'pysat'

Prerequisites

Running any python-side PyQBF.

Solution

The pysat-package is not installed or was not found. If you use a virtual environment, please check if it is active and the package is installed. You can install all python-packages required for PyQBF using the ./requirements.txt file as shown in the installation guide.

Note

This package can not be installed using pip install pysat as this is a different package. The unique package name of PySAT is pip install python-sat

Permission denied when executing execvpe

Error-Message

[QuAPI] [ERROR] [<id>] Could not execvpe! Killing this process. Error: Permission denied

Prerequisites

• using pyqbf.solvers.QuAPI with a custom path

• using pyqbf.solvers.Caqe

• using pyqbf.solvers.Solver with use_quapi=true

• any other usage of QuAPI in the Backend

Solution

This error occurs when the executable targeted by QuAPI does not have permission to be executed. If a custom path is used, please check again if the file specified by the path can be run by the program. If this occurs within the PyQBF-framework, navigate to the ./executables folder from the repository’s root and manually add the corresponding permission using e.g. chmod +x <file>

Deadlock when using Qute and QuAPI

Error-Message

No error message, the solver stays idle and does not return.

Prerequisites

• using pyqbf.solvers.Solver with use_quapi=true and SolverNames.Qute as backend

• using pyqbf.solvers.QuAPI with a custom path to a Qute solver

• any other usage of QuAPI with Qute

Furthermore, no assumptions were provided.

Solution

Currently, there is no known solution for this problem. As it only occurs when using QuAPI without assumptions, we suggest only use this combination when working with assumptions and else use the basic version of Qute.