Troubleshooting

Installation

Python package “pygraphviz”

The installation of pygraphviz can cause errors. You can circumvent this issue by setting the simulation_setting, plot_nx_graph to False. If you need to plot the network graphs (set parameter plot_nx_graph to True) or run all pytests, check if we already have a solution for your OS/distribution:

Ubuntu 18.4: Pygraphviz could not be installed with pip. Solution:

sudo apt-get install python3-dev graphviz libgraphviz-dev pkg-config

pip install pygraphviz

Windows 10 Installing via

pip install -r requirements.txt

results in an error:

error: Microsoft Visual C++ 14.0 is required. Get it with “Build Tools for Visual Studio”: https://visualstudio.microsoft.com/downloads/

You can find fixes on stackoverflow If you have conda installed, activate your environment and run

conda install -c alubbock graphviz pygraphviz

Then you need to configure the dot command on your computer to be able to use graphviz

dot -c

Python package “xlrd”

On Windows there can be issues installing xlrd. This could solve your troubles:

  1. Delete xlrd from requirements.txt

  2. Download the xlrd-1.2.0-py2.py3-none-any.whl file from here.

  3. Copy the file to main directory of the project on your laptop

  4. Install it manually writing pip install xlrd-1.2.0-py2.py3-none-any.whl

Python package “wkhtmltopdf”

There can be issues installing wkhtmltopdf. Solution can be found on the packages documentation.

cbc-solver

While with Ubuntu the installation of the cbc solver should work rather well, even when adding it to the environment variables (like described in the installation instructions) can sometimes not work on Windows. This was experienced with Windows 10.

A workaround is to directly put the cbc.exe file into the root of the MVS repository, ie. in the same folder where also the CHANGELOG.md file is located. Python/Oemof/Pyomo then are able to find the solver.

pyppeteer

If you are using OS X, you might need to install this package separately with conda using:

conda install -c conda-forge pyppeteer

or

conda install -c conda-forge/label/cf202003 pyppeteer

More information is available on their website.

Error messages and MVS termination

Even though we try to keep the error messages of the MVS clear and concise, there might be a some that are harder to understand. This especially applies to error messages that occur due to the termination of the oemof optimization process.

json.decoder.JSONDecodeError

If the error json.decoder.JSONDecodeError is raised, there is a formatting issue with the json file that is used as an input file.

Have you changed the json file manually? Please check for correct formatting, ie. apostrophes, commas, brackets, and so on.

If you have not changed the Json file yourself please consider raising an issue in the github project.