Fix two bugs in Ensemble class (#1162)

* ensure that if we did a temporary cast of a new libE_specs to dict, it gets cast back to a class upon setting. Passthrough nworkers attribute upon setting libE_specs if the Ensemble doesn't have it, but libE_specs does

* fixes and improvements for libE_specs setting and nworkers attributes passthrough, plus a test

* didn't need to do this kind of "passthrough" since the nworkers property returns the correct value

libensemble/ensemble.py

@@ -274,7 +274,7 @@ def __init__(
         self.sim_specs = sim_specs
         self.gen_specs = gen_specs
         self.exit_criteria = exit_criteria
-        self._libE_specs = libE_specs
+        self.libE_specs = libE_specs
         self.alloc_specs = alloc_specs
         self.persis_info = persis_info
         self.executor = executor
@@ -284,7 +284,7 @@ def __init__(
         self.logger = logger
         self.logger.set_level("INFO")
 
-        self.nworkers = 0
+        self._nworkers = 0
         self.is_manager = False
         self.parsed = False
 
@@ -316,23 +316,23 @@ def libE_specs(self, new_specs):
         #   "not" overwrite the internal libE_specs["comms"], but *only* if parse_args
         #   was called. Otherwise we can respect the complete set of provided options.
 
-        # Convert our libE_specs from dict to class, if its a dict
-        if isinstance(self._libE_specs, dict):
-            self._libE_specs = LibeSpecs(**self._libE_specs)
+        # Respect everything if libE_specs isn't set
+        if not hasattr(self, "_libE_specs") or not self._libE_specs:
+            if isinstance(new_specs, dict):
+                self._libE_specs = LibeSpecs(**new_specs)
+            else:
+                self._libE_specs = new_specs
+            return
 
         # Cast new libE_specs temporarily to dict
-        if not isinstance(new_specs, dict):
+        if isinstance(new_specs, LibeSpecs):
             new_specs = new_specs.dict(by_alias=True, exclude_none=True, exclude_unset=True)
 
         # Unset "comms" if we already have a libE_specs that contains that field, that came from parse_args
         if new_specs.get("comms") and hasattr(self._libE_specs, "comms") and self.parsed:
             new_specs.pop("comms")
 
-        # Now finally set attribute if we don't have a libE_specs, otherwise update the internal
-        if not self._libE_specs:
-            self._libE_specs = new_specs
-        else:
-            self._libE_specs.__dict__.update(**new_specs)
+        self._libE_specs.__dict__.update(**new_specs)
 
     def _refresh_executor(self):
         Executor.executor = self.executor or Executor.executor
@@ -390,10 +390,15 @@ def run(self) -> (npt.NDArray, dict, int):
 
         return self.H, self.persis_info, self.flag
 
-    def _nworkers(self):
-        if self.nworkers:
-            return self.nworkers
-        return self.libE_specs.nworkers
+    @property
+    def nworkers(self):
+        return self._nworkers or self.libE_specs.nworkers
+
+    @nworkers.setter
+    def nworkers(self, value):
+        self._nworkers = value
+        if self.libE_specs:
+            self.libE_specs.nworkers = value
 
     def _get_func(self, loaded):
         """Extracts user function specified in loaded dict"""
@@ -532,7 +537,7 @@ def add_random_streams(self, num_streams: int = 0, seed: str = ""):
         if num_streams:
             nstreams = num_streams
         else:
-            nstreams = self._nworkers()
+            nstreams = self.nworkers
 
         self.persis_info = add_unique_random_streams(self.persis_info, nstreams + 1, seed=seed)
         return self.persis_info

libensemble/tests/unit_tests/test_ensemble.py

@@ -13,11 +13,31 @@ def test_ensemble_init():
 
     e = Ensemble(parse_args=True)
     assert hasattr(e.libE_specs, "comms"), "internal parse_args() didn't populate defaults for class's libE_specs"
+    assert hasattr(e, "nworkers"), "nworkers should've passed from libE_specs to Ensemble class"
     assert e.is_manager, "parse_args() didn't populate defaults for class's libE_specs"
 
     assert e.logger.get_level() == 20, "Default log level should be 20."
 
 
+def test_ensemble_parse_args_false():
+    from libensemble.ensemble import Ensemble
+    from libensemble.specs import LibeSpecs
+
+    e = Ensemble()  # parse_args defaults to False
+    e.libE_specs = {"comms": "local", "nworkers": 4}
+    assert hasattr(e, "nworkers"), "nworkers should've passed from libE_specs to Ensemble class"
+    assert isinstance(e.libE_specs, LibeSpecs), "libE_specs should've been cast to class"
+
+    # test pass attribute as dict
+    e = Ensemble(libE_specs={"comms": "local", "nworkers": 4})
+    assert hasattr(e, "nworkers"), "nworkers should've passed from libE_specs to Ensemble class"
+    assert isinstance(e.libE_specs, LibeSpecs), "libE_specs should've been cast to class"
+
+    # test that adjusting Ensemble.nworkers also changes libE_specs
+    e.nworkers = 8
+    assert e.libE_specs.nworkers == 8, "libE_specs nworkers not adjusted"
+
+
 def test_from_files():
     """Test that Ensemble() specs dicts resemble setup dicts"""
     from libensemble.ensemble import Ensemble
@@ -91,6 +111,7 @@ def test_full_workflow():
         ),
         exit_criteria=ExitCriteria(gen_max=101),
     )
+
     ens.add_random_streams()
     ens.run()
     if ens.is_manager:
@@ -146,6 +167,7 @@ def test_flakey_workflow():
 
 if __name__ == "__main__":
     test_ensemble_init()
+    test_ensemble_parse_args_false()
     test_from_files()
     test_bad_func_loads()
     test_full_workflow()