[BugFix] Fix CompositeSpec.to_numpy method (#931)

Author: riiswa

test/test_specs.py

@@ -446,6 +446,14 @@ def test_is_in(self, is_complete, device, dtype):
             r = ts.rand()
             assert ts.is_in(r)
 
+    def test_to_numpy(self, is_complete, device, dtype):
+        ts = self._composite_spec(is_complete, device, dtype)
+        for _ in range(100):
+            r = ts.rand()
+            for key, value in ts.to_numpy(r).items():
+                spec = ts[key]
+                assert (spec.to_numpy(r[key]) == value).all()
+
     @pytest.mark.parametrize("shape", [[], [3]])
     def test_project(self, is_complete, device, dtype, shape):
         ts = self._composite_spec(is_complete, device, dtype)

torchrl/data/tensor_specs.py

@@ -1947,7 +1947,7 @@ def clone(self) -> CompositeSpec:
         )
 
     def to_numpy(self, val: TensorDict, safe: bool = True) -> dict:
-        return {key: self[key]._to_numpy(val) for key, val in val.items()}
+        return {key: self[key].to_numpy(val) for key, val in val.items()}
 
     def zero(self, shape=None) -> TensorDictBase:
         if shape is None: