Frequently Asked Questions (FAQ)¶

This is a list of frequently asked questions about Tarantella. Please feel free to suggest new ones!

Question

How can I ssh to localhost without password?

In order to run Tarantella programs, you will need to be able to ssh to localhost without password. In order to do that generate ssh keys first:

cd ~/.ssh
ssh-keygen

Make sure not to overwrite existing keys. When asked for a passphrase, Enter passphrase (empty for no passphrase):, simply leave empty and return with enter. Also take specific care to set correct user rights on all files in .ssh, cf. for instance here. Next, append the public key to the authorized_keys file:

cat id_rsa.pub >> authorized_keys

Now, install and start an ssh server, e.g., openssh-server on Fedora. More details can be found for instance here.

Question

I get an execution error GPI library initialization incorrect environment vars when trying to run my script. What shall I do?

Most likely you are running your program with python my_script.py or ./my_script.py. Please make sure to execute your code with tarantella my_script.py instead.

Question

I get an execution error GPI library initialization general error. What shall I do?

This error occurs when the GASPI library tries to connect to a previously used socket, that is not yet released. Try to re-run your code after a short while so that the port becomes available again.

Question

The execution seems to stall. What shall I do?

Please kill any processes that might be still running from a previous (aborted) call to tarantella.

Question

When trying to build Tarantella, CMake cannot find pybind11:
Could not find a package configuration file provided by "pybind11" with any
of the following names: [...]
What shall I do?

This error occurs when pybind11 is installed using pip. Please instead use conda, as recommended in the installation guide.

Question

When trying to build Tarantella, CMake does not detect the Python interpreter from the active conda environment. What shall I do?

You will need to manually add the path to the conda environment’s bin directory to your PATH. You will also need to specify the path to the python library on the command line when configuring Tarantella:

PATH_TO_CONDA_ENV=/path/to/conda/env
export PATH=${PATH_TO_CONDA_ENV}/bin:${PATH}
cmake -DPYTHON_EXECUTABLE=${PATH_TO_CONDA_ENV}/bin/python \
      -DPYTHON_LIBRARY=${PATH_TO_CONDA_ENV}/lib ../