Remove Sample Rate Rounding

activitysim/abm/tables/households.py

@@ -99,10 +99,7 @@ def households(state: workflow.State) -> pd.DataFrame:
         if households_sample_size == 0:
             sample_rate = 1
         else:
-            # TODO: do not round, keep full precision to avoid creating 0 sample_rate for small samples
-            # Existing CI tests will fail when performing bitwise comparisons with the unrounded sample_rate
-            # We should update the CI tests
-            sample_rate = round(households_sample_size / tot_households, 3)
+            sample_rate = households_sample_size / tot_households
 
         df["sample_rate"] = sample_rate
 

activitysim/abm/test/test_misc/test_sample_rate.py

@@ -0,0 +1,55 @@
+# ActivitySim
+# See full license in LICENSE.txt.
+import pandas as pd
+
+import pytest
+
+from activitysim.core import workflow
+
+
+@pytest.fixture(scope="session")
+def example_root(tmp_path_factory):
+    root = tmp_path_factory.mktemp("example")
+    config_dir = root / "configs"
+    config_dir.mkdir()
+
+    data_dir = root / "data"
+    data_dir.mkdir()
+
+    return root
+
+
+@pytest.fixture(scope="module")
+def state(example_root) -> workflow.State:
+
+    settings = """
+        input_table_list:
+            - tablename: households
+              filename: households.csv
+              index_col: household_id
+
+        households_sample_size: 2
+        """
+
+    settings_file = example_root / "configs" / "settings.yaml"
+    settings_file.write_text(settings)
+
+    households = pd.DataFrame(
+        {
+            "household_id": range(1, 100001),
+            "home_zone_id": [1, 2] * 50000,
+        }
+    )
+    households.to_csv(example_root / "data" / "households.csv", index=False)
+
+    state = workflow.State.make_default(example_root)
+
+    return state
+
+
+def test_sample_rate_calculation(state):
+    households_df = state.get_dataframe("households")
+    sample_rate = households_df["sample_rate"].iloc[0]
+    assert (
+        sample_rate == 0.00002
+    ), f"Expected sample rate of 0.00002, but got {sample_rate}"