Fix backward compatability for older versions of lightning

torchmetrics/metric.py

@@ -24,6 +24,7 @@
 from torchmetrics.utilities import apply_to_collection
 from torchmetrics.utilities.data import _flatten, dim_zero_cat, dim_zero_mean, dim_zero_sum
 from torchmetrics.utilities.distributed import gather_all_tensors
+from torchmetrics.utilities.imports import _LIGHTNING_GREATER_THAN_1_2_8
 
 
 class Metric(nn.Module, ABC):
@@ -256,7 +257,10 @@ def reset(self):
  """
  This method automatically resets the metric state variables to their default value.
  """
- self._computed = None
+ # lower lightning versions requires this implicitly to log metric objects correctly
+ # in self.log
+ if _LIGHTNING_GREATER_THAN_1_2_8:
+ self._computed = None
 
  for attr, default in self._defaults.items():
  current_val = getattr(self, attr)

torchmetrics/utilities/imports.py

@@ -64,3 +64,4 @@ def _compare_version(package: str, op, version) -> bool:
 _TORCH_LOWER_1_6 = _compare_version("torch", operator.lt, "1.6.0")
 _TORCH_GREATER_EQUAL_1_6 = _compare_version("torch", operator.ge, "1.6.0")
 _TORCH_GREATER_EQUAL_1_7 = _compare_version("torch", operator.ge, "1.7.0")
+_LIGHTNING_GREATER_THAN_1_2_8 = _compare_version("pytorch_lightning", operator.gt, "1.2.8")