Ok i suppose every piece of software works individually ok,
I tried several approaches and they work, ok these are the steps i followed:
1.- I’m on Windows, i downloaded the GNU Octave 6.3.0 and installed it, i changed the installation directory to one without spaces in its name, as:
2.- Before installing other software i install the symbolic package not by running the
forge command, but instead by going to the download page of the project as it says that windows can have some problems with the dependencies the package requires, which i guess from the error in your message is the case the package isn’t working.
In this case download the latest symbolic package file
symbolic-win-py-bundle-2.9.0.tar.gz file from Releases · cbm755/octsympy · GitHub
3.- I move the
symbolic-win-py-bundle-2.9.0.tar.gz file to an appropiate directory, and i open Octave, i change my working directory to the directory containing the symbolic package installer and i run in the octave command line:
pkg install symbolic-win-py-bundle-2.9.0.tar.gz
Octave unpacks and installs the symbolic package.
At this point i test that the installation is correct by running commands like:
pkg load symbolic
4.- I verified that the symbolic package installed from the tar works fine, then I install miniconda, since the newest one uses python 3.9 I think but that one still has some issues and some packages I need require an older python I go for the miniconda installation with python 3.7.
5.- Once miniconda has been installed i install jupyter notebooks with the jupyter lab command you used
conda install -c conda-forge jupyterlab
6.- When jupyter has finished installing I install the Octave kernel, i recommend not mixing packages in miniconda via pip and conda installation commands on top of each other, instead of using pip i run the command:
conda install octave_kernel
you also mentioned that you have already set the enviromental variable pointing to the octave executable so the jupyter notebook should be able to load the conection to octave.
7.- Finally i run the same example to check that everything works: