fix: convert tuple S-param keys to string labels in all_models notebook

Fixes matplotlib ValueError when tuple S-parameter keys (e.g., (1, 2)) are passed directly as plot labels. str() conversion ensures compatibility.

Author: Alex-l-r

notebooks/all_models.ipynb

@@ -264,7 +264,7 @@
     "f = jnp.linspace(1e9, 25e9, 201)\n",
     "S = gamma_0_load(f=f, gamma_0=0.5 + 0.5j, n_ports=2)\n",
     "for key in S:\n",
-    "    plt.plot(f / 1e9, abs(S[key]) ** 2, label=key)\n",
+    "    plt.plot(f / 1e9, abs(S[key]) ** 2, label=str(key))\n",
     "plt.ylim(-0.05, 1.05)\n",
     "plt.xlabel(\"Frequency [GHz]\")\n",
     "plt.ylabel(\"S\")\n",

notebooks/src/all_models.py

@@ -121,7 +121,7 @@
 f = jnp.linspace(1e9, 25e9, 201)
 S = gamma_0_load(f=f, gamma_0=0.5 + 0.5j, n_ports=2)
 for key in S:
-    plt.plot(f / 1e9, abs(S[key]) ** 2, label=key)
+    plt.plot(f / 1e9, abs(S[key]) ** 2, label=str(key))
 plt.ylim(-0.05, 1.05)
 plt.xlabel("Frequency [GHz]")
 plt.ylabel("S")