Add StatsBijection.n_samplers property

Author: michaelosthege

pymc/step_methods/compound.py

@@ -187,6 +187,10 @@ def __init__(self, sampler_stats_dtypes: Sequence[Mapping[str, type]]) -> None:
             for s, names_dtypes in enumerate(sampler_stats_dtypes)
         ]
 
+    @property
+    def n_samplers(self) -> int:
+        return len(self._stat_groups)
+
     def map(self, stats_list: Sequence[Mapping[str, Any]]) -> StatsDict:
         """Combine stats dicts of multiple samplers into one dict."""
         stats_dict = {}

pymc/tests/step_methods/test_compound.py

@@ -116,6 +116,7 @@ def test_stats_bijection(self):
             {"a": float, "c": int},
         ]
         bij = StatsBijection(step_stats_dtypes)
+        assert bij.n_samplers == 2
         stats_l = [
             dict(a=1.5, b=3),
             dict(a=2.5, c=4),