How to toggle channel ON/OFF

[JackKelly1]

I am currently trying to simulate a 40 channel link and want the ability to turn certain channels off. I have tried changing sim_params._nli_params._computed_channels but this only changes the calculations when using raman fibers. Please could you tell me how to toggle the channels when using SSMF for example?

Thank you.

[jktjkt]

This is currently not possible via the standard frontend (XLS and JSON files), only by manipulating the Python code directly. We're working on making it fully supported, along with non-uniform modulation rates.

[JackKelly1]

Thank you for the response @jktjkt. Please could you describe where in cli_examples.py (I assume) the changes should be made?

[jktjkt]

If you're comfortable with Python, take a look at the patch series, but beware, it's a bit more involved. By all means please provide feedback.

For a quick-n-dirty approach, you might try overriding the create_input_spectral_information function which is where we take the user's input about the uniform grid. Just skipping a channel or two should be reasonably straightforward. Here's an untested patch:

diff --git a/gnpy/core/info.py b/gnpy/core/info.py
index 1d0ac51..db288fb 100644
--- a/gnpy/core/info.py
+++ b/gnpy/core/info.py
@@ -50,7 +50,7 @@ def create_input_spectral_information(f_min, f_max, roll_off, baud_rate, power,
         pref=Pref(pref, pref, lin2db(nb_channel)),
         carriers=[
             Channel(f, (f_min + spacing * f),
-                    baud_rate, roll_off, Power(power, 0, 0), 0, 0) for f in range(1, nb_channel + 1)
+                    baud_rate, roll_off, Power(power, 0, 0), 0, 0) for f in range(1, nb_channel + 1) if f != 10
         ]
     )
     return si

[caffery-chen]

Is it possible to simulate non-uniform modulation rates in the latest release by manipulating e.g. the bandwidth when creating spectrum via SI ?

[jktjkt]

My understanding is that the results won't be accurate. There's a new version of the simulation engine that I pointed to where this error is addressed. It's currently a work-in-progress, people are working in integrating that library with the rest of the GNPy. We're targeting a release with that for some time around OFC, but no guarantees on that one.