Allow random routes to vary across traffic groups. (#2112)

* Allow random routes to vary across traffic groups.

* Update changelog.

* Vary seed using interation instead.

* Remove unused imports.

CHANGELOG.md

@@ -13,6 +13,7 @@ Copy and pasting the git commit messages is __NOT__ enough.
 ### Changed
 ### Deprecated
 ### Fixed
+- Fixed an issue where `RandomRoute` would always give the same route across traffic groups in scenario studio.
 - Fixed an issue where `SMARTS` might not be explicitly destroyed in the `ros_driver`.
 - Fixed issue where `SumoTrafficSimulation` could get locked up on reset if a scenario had only 1 map but multiple scenario variations.
 - Fixed an issue where an out-of-scope method reference caused a pickling error.

scenarios/sumo/intersections/4lane/scenario.py

@@ -74,18 +74,20 @@
     ),
 ]
 
+variations = 40
 scenario = Scenario(
     traffic={
-        "basic": Traffic(
+        f"t{i}": Traffic(
             flows=[
                 Flow(
                     route=RandomRoute(),
-                    repeat_route=True,
                     rate=3600,
+                    randomly_spaced=True,
                     actors={TrafficActor(name="car"): 1.0},
                 )
             ]
         )
+        for i in range(variations)
     },
     ego_missions=ego_missions,
     map_spec=MapSpec(

smarts/sstudio/generators.py

@@ -30,10 +30,12 @@
 import tempfile
 from typing import Optional
 
+import numpy as np
 from yattag import Doc, indent
 
 from smarts.core.road_map import RoadMap
 from smarts.core.utils.file import make_dir_in_smarts_log_dir, replace
+from smarts.core.utils.math import wrap_value
 
 from . import types
 
@@ -184,6 +186,7 @@ def plan_and_save(
 
             from smarts.core.utils.sumo import sumolib
 
+            int32_limits = np.iinfo(np.int32)
             duarouter_path = sumolib.checkBinary("duarouter")
             subprocess.check_call(
                 [
@@ -197,7 +200,7 @@ def plan_and_save(
                     "--output-file",
                     route_path,
                     "--seed",
-                    str(seed),
+                    str(wrap_value(seed, int32_limits.min, int32_limits.max)),
                     "--ignore-errors",
                     "false",
                     "--no-step-log",

smarts/sstudio/genscenario.py

@@ -35,6 +35,7 @@
 import cloudpickle
 import yaml
 
+import smarts.core
 from smarts.core.default_map_builder import find_mapfile_in_dir
 from smarts.core.utils.file import file_md5_hash, path2hash, pickle_hash
 from smarts.core.utils.logging import timeit
@@ -164,6 +165,7 @@ def gen_scenario(
     """
     # XXX: For now this simply coalesces the sub-calls but in the future this allows
     #      us to simplify our serialization between SStudio and SMARTS.
+    smarts.core.seed(seed)
 
     scenario_dir = os.path.abspath(str(output_dir))
     build_dir = os.path.join(scenario_dir, "build")
@@ -242,12 +244,14 @@ def gen_scenario(
         db_conn, scenario.traffic, artifact_paths, obj_hash, map_needs_rebuild
     ):
         with timeit("traffic", logger.info):
-            for name, traffic in scenario.traffic.items():
+
+            for iteration, (name, traffic) in enumerate(scenario.traffic.items()):
+                derived_seed = seed + iteration
                 gen_traffic(
                     scenario=scenario_dir,
                     traffic=traffic,
                     name=name,
-                    seed=seed,
+                    seed=derived_seed,
                     map_spec=map_spec,
                 )
             _update_artifacts(db_conn, artifact_paths, obj_hash)