Add generation node string to base trial (facebook#3355)

Summary:
Pull Request resolved: facebook#3355

This will help expose the methods used to generate trials to the user, e.g., via experiment.to_df, matching legacy behavior in exp_to_df.

Differential Revision: D68909600

Reviewed By: saitcakmak

ax/core/base_trial.py

@@ -17,7 +17,7 @@
 from ax.core.arm import Arm
 from ax.core.data import Data
 from ax.core.formatting_utils import data_and_evaluations_from_raw_data
-from ax.core.generator_run import GeneratorRun
+from ax.core.generator_run import GeneratorRun, GeneratorRunType
 from ax.core.map_data import MapData
 from ax.core.map_metric import MapMetric
 from ax.core.metric import Metric, MetricFetchResult
@@ -26,13 +26,18 @@
 from ax.core.types import TCandidateMetadata, TEvaluationOutcome
 from ax.exceptions.core import UnsupportedError
 from ax.utils.common.base import SortableBase
+from ax.utils.common.constants import Keys
 from pyre_extensions import none_throws
 
 
 if TYPE_CHECKING:
     # import as module to make sphinx-autodoc-typehints happy
     from ax import core  # noqa F401
 
+MANUAL_GENERATION_METHOD_STR = "Manual"
+UNKNOWN_GENERATION_METHOD_STR = "Unknown"
+STATUS_QUO_GENERATION_METHOD_STR = "Status Quo"
+
 
 def immutable_once_run(func: Callable) -> Callable:
     """Decorator for methods that should throw Error when
@@ -659,6 +664,44 @@ def mark_arm_abandoned(self, arm_name: str, reason: str | None = None) -> BaseTr
             "Use `trial.mark_abandoned` if applicable."
         )
 
+    @property
+    def generation_method_str(self) -> str:
+        """Returns the generation method(s) used to generate this trial's arms,
+        as a human-readable string (e.g. 'Sobol', 'BoTorch', 'Manual', etc.).
+        Returns a comma-delimited string if multiple generation methods were used.
+        """
+        if (
+            warm_start_model_key := self._properties.get(Keys.WARMSTART_TRIAL_MODEL_KEY)
+            is not None
+        ):
+            # TODO: Use model key provided during warm-starting if present, since the
+            # generator run may not be present on warm-started trials.
+            return warm_start_model_key
+
+        generation_methods = {
+            none_throws(generator_run._model_key)
+            for generator_run in self.generator_runs
+            if generator_run._model_key is not None
+        }
+
+        # Add generator-run-type strings for non-ModelBridge generator runs.
+        gr_type_name_to_str = {
+            GeneratorRunType.MANUAL.name: MANUAL_GENERATION_METHOD_STR,
+            GeneratorRunType.STATUS_QUO.name: STATUS_QUO_GENERATION_METHOD_STR,
+        }
+        generation_methods |= {
+            gr_type_name_to_str[generator_run.generator_run_type]
+            for generator_run in self.generator_runs
+            if generator_run.generator_run_type in gr_type_name_to_str
+        }
+
+        return (
+            # Sort for deterministic output
+            ", ".join(sorted(generation_methods))
+            if generation_methods
+            else UNKNOWN_GENERATION_METHOD_STR
+        )
+
     def _mark_failed_if_past_TTL(self) -> None:
         """If trial has TTL set and is running, check if the TTL has elapsed
         and mark the trial failed if so.

ax/core/tests/test_batch_trial.py

@@ -13,12 +13,16 @@
 
 import numpy as np
 from ax.core.arm import Arm
+from ax.core.base_trial import (
+    MANUAL_GENERATION_METHOD_STR,
+    TrialStatus,
+    UNKNOWN_GENERATION_METHOD_STR,
+)
 from ax.core.batch_trial import BatchTrial, GeneratorRunStruct
 from ax.core.experiment import Experiment
 from ax.core.generator_run import GeneratorRun, GeneratorRunType
 from ax.core.parameter import FixedParameter, ParameterType
 from ax.core.search_space import SearchSpace
-from ax.core.trial_status import TrialStatus
 from ax.exceptions.core import UnsupportedError
 from ax.runners.synthetic import SyntheticRunner
 from ax.utils.common.testutils import TestCase
@@ -76,9 +80,12 @@ def test_BasicProperties(self) -> None:
             self.batch.generator_run_structs[0].generator_run.generator_run_type,
             GeneratorRunType.MANUAL.name,
         )
+        self.assertEqual(self.batch.generation_method_str, MANUAL_GENERATION_METHOD_STR)
 
-        # Test empty arms
-        self.assertEqual(len(self.experiment.new_batch_trial().abandoned_arms), 0)
+        # Test empty trial
+        t = self.experiment.new_batch_trial()
+        self.assertEqual(len(t.abandoned_arms), 0)
+        self.assertEqual(t.generation_method_str, UNKNOWN_GENERATION_METHOD_STR)
 
     def test_UndefinedSetters(self) -> None:
         with self.assertRaises(NotImplementedError):
@@ -480,6 +487,9 @@ def test_clone_to(self, _) -> None:
         # test cloning with clear_trial_type=True
         new_batch_trial = batch.clone_to(clear_trial_type=True)
         self.assertIsNone(new_batch_trial.trial_type)
+        self.assertEqual(
+            new_batch_trial.generation_method_str, MANUAL_GENERATION_METHOD_STR
+        )
 
     def test_Runner(self) -> None:
         # Verify BatchTrial without runner will fail
@@ -667,9 +677,12 @@ def test_TTL(self) -> None:
         self.assertIn(2, self.experiment.trial_indices_by_status[TrialStatus.FAILED])
 
     def test_get_candidate_metadata_from_all_generator_runs(self) -> None:
+        self.assertEqual(self.batch.generation_method_str, MANUAL_GENERATION_METHOD_STR)
         gr_1 = get_generator_run()
         gr_2 = get_generator_run2()
         self.batch.add_generator_run(gr_1)
+        self.assertEqual(self.batch.generation_method_str, "Manual, Sobol")
+
         # Arms are named when adding GR to trial, so reassign to have a GR that has
         # names arms.
         gr_1 = self.batch._generator_run_structs[-1].generator_run
@@ -719,6 +732,7 @@ def test_get_candidate_metadata_from_all_generator_runs(self) -> None:
                 cand_metadata_expected[arm.name],
                 self.batch._get_candidate_metadata(arm.name),
             )
+        self.assertEqual(self.batch.generation_method_str, "Manual, Sobol")
 
     def test_Sortable(self) -> None:
         new_batch_trial = self.experiment.new_batch_trial()

ax/core/tests/test_trial.py

@@ -12,7 +12,12 @@
 from unittest.mock import Mock, patch
 
 import pandas as pd
-from ax.core.base_trial import BaseTrial, TrialStatus
+from ax.core.base_trial import (
+    BaseTrial,
+    MANUAL_GENERATION_METHOD_STR,
+    TrialStatus,
+    UNKNOWN_GENERATION_METHOD_STR,
+)
 from ax.core.data import Data
 from ax.core.generator_run import GeneratorRun, GeneratorRunType
 from ax.core.runner import Runner
@@ -87,10 +92,13 @@ def test_basic_properties(self) -> None:
         self.assertEqual(
             self.trial.generator_run.generator_run_type, GeneratorRunType.MANUAL.name
         )
+        self.assertEqual(self.trial.generation_method_str, MANUAL_GENERATION_METHOD_STR)
 
         # Test empty arms
+        t = self.experiment.new_trial()
         with self.assertRaises(AttributeError):
-            self.experiment.new_trial().arm_weights
+            t.arm_weights
+        self.assertEqual(t.generation_method_str, UNKNOWN_GENERATION_METHOD_STR)
 
         self.trial.mark_running(no_runner_required=True)
         self.assertTrue(self.trial.status.is_running)

ax/utils/common/constants.py

@@ -93,4 +93,5 @@ class Keys(str, Enum):
     TASK_FEATURES = "task_features"
     TRIAL_COMPLETION_TIMESTAMP = "trial_completion_timestamp"
     WARM_START_REFITTING = "warm_start_refitting"
+    WARMSTART_TRIAL_MODEL_KEY = "generation_model_key"
     X_BASELINE = "X_baseline"