node connection fixes

flatland/envs/grid4_generators_utils.py

@@ -125,7 +125,7 @@ def connect_from_nodes(rail_trans, rail_array, start, end):
             if new_trans == 0:
                 # end-point
                 # need to flip direction because of how end points are defined
-                new_trans = rail_trans.set_transition(new_trans, current_dir, new_dir, 1)
+                new_trans = 0
             else:
                 # into existing rail
                 new_trans = rail_trans.set_transition(new_trans, current_dir, new_dir, 1)
@@ -187,7 +187,7 @@ def connect_to_nodes(rail_trans, rail_array, start, end):
             new_trans_e = rail_array[end_pos]
             if new_trans_e == 0:
                 # end-point
-                new_trans_e = rail_trans.set_transition(new_trans_e, new_dir, new_dir, 1)
+                new_trans_e = 0
             else:
                 # into existing rail
                 new_trans_e = rail_trans.set_transition(new_trans_e, new_dir, new_dir, 1)

tests/test_flatland_env_sparse_rail_generator.py

+import time
+
 import numpy as np
 
 from flatland.envs.generators import sparse_rail_generator, realistic_rail_generator
@@ -31,8 +33,9 @@ def test_sparse_rail_generator():
                                                        num_neighb=2,  # Number of connections to other cities
                                                        seed=5,  # Random seed
                                                        ),
-                  number_of_agents=10,
+                  number_of_agents=1,
                   obs_builder_object=GlobalObsForRailEnv())
     # reset to initialize agents_static
     env_renderer = RenderTool(env, gl="PILSVG", )
     env_renderer.render_env(show=True, show_observations=True, show_predictions=False)
+    time.sleep(2)