Fix if ISLs go out of range

satgenpy/satgen/dynamic_state/generate_dynamic_state.py

@@ -129,30 +129,37 @@ def generate_dynamic_state_at(
         print("\nISL INFORMATION")
 
     # ISL edges
-    isls_valid = 0
-    isls_invalid = 0
+    total_num_isls = 0
     num_isls_per_sat = [0] * len(satellites)
     sat_neighbor_to_if = {}
     for (a, b) in list_isls:
 
-        # Only ISLs which are close enough are considered
+        # ISLs are not permitted to exceed their maximum distance
+        # TODO: Technically, they can (could just be ignored by forwarding state calculation),
+        # TODO: but practically, defining a permanent ISL between two satellites which
+        # TODO: can go out of distance is generally unwanted
         sat_distance_m = sat_distance(satellites[a], satellites[b], str(time))
-        if sat_distance_m <= max_isl_length_m:
-            sat_net_graph_only_satellites_with_isls.add_edge(
-                a, b, weight=sat_distance_m
+        if sat_distance_m > max_isl_length_m:
+            raise ValueError(
+                "The distance between two satellites (%d and %d) "
+                "with an ISL exceeded the maximum ISL length (%.2fm > %.2fm at t=%dns)"
+                % (a, b, sat_distance_m, max_isl_length_m, time_since_epoch_ns)
             )
-            isls_valid += 1
-            sat_neighbor_to_if[(a, b)] = num_isls_per_sat[a]
-            sat_neighbor_to_if[(b, a)] = num_isls_per_sat[b]
-            num_isls_per_sat[a] += 1
-            num_isls_per_sat[b] += 1
-        else:
-            isls_invalid += 1
+
+        # Add to networkx graph
+        sat_net_graph_only_satellites_with_isls.add_edge(
+            a, b, weight=sat_distance_m
+        )
+
+        # Interface mapping of ISLs
+        sat_neighbor_to_if[(a, b)] = num_isls_per_sat[a]
+        sat_neighbor_to_if[(b, a)] = num_isls_per_sat[b]
+        num_isls_per_sat[a] += 1
+        num_isls_per_sat[b] += 1
+        total_num_isls += 1
 
     if enable_verbose_logs:
         print("  > Total ISLs............. " + str(len(list_isls)))
-        print("    >> Valid ISLs (used)... " + str(isls_valid))
-        print("    >> Invalid ISLs........ " + str(isls_invalid))
         print("  > Min. ISLs/satellite.... " + str(np.min(num_isls_per_sat)))
         print("  > Max. ISLs/satellite.... " + str(np.max(num_isls_per_sat)))