gnpy-transmission-example / sim_params.json

[GanbaruDM]

Dear contributors,
I am a graduate student and I am using your QoT-E to perform some simulations in my thesis.
I am gaining confidence with the tool thanks to the youtube video uploaded online. I performed my first simulations using the branch 2020-ofc because it contains the examples/transmission_main_example.py. I would like to use the newest version 2.2
however in the master branch I can not find the gnpy-transmission-example and neither the npy-path-request.

While simulating with the branch ofc-2020 I am not able to obtain the results with both the gn and the ggn model in order to compare them. Eventhough I am passing the --sim-params, I obtain the same simulation results setting "flag_raman": false, or "flag_raman": true,. and as well setting "nli_method_name": "gn_model_analytic", or "nli_method_name": "gn_model_analytic",. Probably I am not understanding properly these parameters. Since I have 35 channels i have set "raman_computed_channels": [1,35], Does "wdm_grid_size" indicate the superchannel bandwidth?

Finally I have even tried to change manually Fiber to RamanFiber in the topology .json file but doing so I got one error (see the attached Fig). Could be possible to disable the auto-design feature?

Thank you very much for your patience.

[ojnas]

Hi @GanbaruDM,

gnpy-transmission-example and gnpy-path-request will be available if you install the Python package according to instructions here:

https://gnpy.readthedocs.io/en/master/install.html#using-python-on-your-computer

Specifically, this step is required:

pip install --editable . # note the trailing dot

Note that the gnpy-transmission-example and gnpy-path-request scripts just import the corresponding function from gnpy.tools.cli_examples and run it.

Currently, Raman simulation and ggn model are only supported by the RamanFiber element. I don't see any attached file so I don't know what error you get.

[ojnas]

Thanks, looks like you discovered a bug in the Raman code. If a RamanFiber is shorter than the space_resolution defined in the sim-params file, the simulation crashes. Could you confirm if this is the case in your simulation? Anyway, a proposed fix for this is waiting here:

https://review.gerrithub.io/c/Telecominfraproject/oopt-gnpy/+/517505

[GanbaruDM]

Yes, I confirm that this is the case! Setting the resolution as "space_resolution": 10e3, (10 km, which is the length of the shorter RamanFiber span) the QoT-E does not get any error and I obtain the GGN model values.

[GanbaruDM]

I tried to implement the fix following your solution: I changed z_resolution = self.raman_params.space_resolution to z_resolution = min(self.raman_params.space_resolution, fiber_length) in gnpy/core/science_utils.py however for some reason this is not solving the issue. Anyway I can easily set the space resolution manually to avoid any problems.
Thanks

[ojnas]

I tried to implement the fix following your solution: I changed z_resolution = self.raman_params.space_resolution to z_resolution = min(self.raman_params.space_resolution, fiber_length) in gnpy/core/science_utils.py however for some reason this is not solving the issue.

Did you pip install GNPy from a cloned local directory with the --editable option? Without this option, changes you make in your local directory will not have any effect.

[jktjkt]

Just FYI, the fix has been merged. If you're using a git checkout and have installed locally before via pip install -e ., a simple git pullwill do.