Finish example 5.

examples/5_agent_zoo.py

@@ -5,10 +5,11 @@
 import sys
 from pathlib import Path
 
-from examples.tools.argument_parser import empty_parser
-
+# This may be necessary to get the repository root into path
 SMARTS_REPO_PATH = Path(__file__).parents[1].absolute()
 sys.path.insert(0, str(SMARTS_REPO_PATH))
+
+from examples.tools.argument_parser import empty_parser
 from smarts.core.agent import Agent
 from smarts.core.agent_interface import AgentInterface, AgentType
 from smarts.zoo import registry
@@ -30,19 +31,51 @@ def rla_entrypoint(max_episode_steps=1000):
 
 
 def main():
+    name = "random_lane_control-v0"
+    print(f"=== Before registering `{name}` ===")
+    print(registry.agent_registry)
     registry.register(
-        "random_lane_control-v0", rla_entrypoint
+        name, rla_entrypoint
     )  # This registers "__main__:random_lane_control-v0"
+    print(f"=== After registering `{name}` ===")
     print(registry.agent_registry)
 
-    agent_spec = registry.make(locator="__main__:random_lane_control-v0")
+    agent_spec = registry.make(locator=f"__main__:{name}")
     agent_interface = agent_spec.interface
     agent = agent_spec.build_agent()
     # alternatively this will build the agent
     agent, agent_interface = registry.make_agent(
-        locator="__main__:random_lane_control-v0"
+        locator=f"__main__:{name}" 
+    )
+    # just "random_lane_control-v0" also works because the agent has already been registered in this file.
+    agent, agent_interface = registry.make_agent(
+        locator=name 
     )
 
+    locator = "zoo.policies:chase-via-points-agent-v0"
+    # Here is an example of using the module component of the locator to dynamically load agents:
+    agent, agent_interface = registry.make_agent(
+        locator=locator
+    )
+    print(f"=== After loading `{locator}` ===")
+    print(registry.agent_registry)
+
+
+    ## This agent requires installation
+    # agent, agent_interface = registry.make_agent(
+    #     locator="zoo.policies:discrete-soft-actor-critic-agent-v0"
+    # )
+
+    locator = "non_existing.module:md-v44"
+    try:
+        agent, agent_interface = registry.make_agent(
+            locator="non_existing.module:md-v44"
+        )
+    except (ModuleNotFoundError, ImportError):
+        print(f"Such as with '{locator}'. Module resolution can fail if the module cannot be found "
+              "from the PYTHONPATH environment variable apparent as `sys.path` in python.")
+
+
 
 if __name__ == "__main__":
     parser = empty_parser(Path(__file__).stem)

examples/6_experiment_base.py

@@ -84,7 +84,7 @@ class ExperimentCfg:
     config_name="experiment_default",
     version_base=None,
 )
-def main(experiment_config: ExperimentCfg) -> None:
+def experiment_main(experiment_config: ExperimentCfg) -> None:
     typed_experiment_config: ExperimentCfg = OmegaConf.to_object(cfg=experiment_config)
     print(f"Loading configuration from `{CONFIG_LOCATION}`")
     if typed_experiment_config.show_config:
@@ -147,4 +147,4 @@ def main(experiment_config: ExperimentCfg) -> None:
 
 
 if __name__ == "__main__":
-    main()
+    experiment_main()

smarts/core/utils/class_factory.py

@@ -109,8 +109,7 @@ def find_factory(self, locator):
         self._raise_on_invalid_locator(locator)
 
         mod_name, _, name = locator.partition(":")
-
-        if name is not None:
+        if name != "":
             # There is a module component.
             try:
                 # Import the module so that the agent may register itself in the index
@@ -157,7 +156,7 @@ def __repr__(self) -> str:
         out = ""
         for i, name in enumerate(self.index.keys()):
             out = f"{out}{name.ljust(max_justify)} "
-            if i % columns == 0:
+            if i % columns == 0 and len(self.index) != i + 1:
                 out += "\n"
         out += "\n"