Better error message if no loss was returned from model.training_step() (#294)

2019-10-04 11:15:19 +00:00 · 2019-10-04 11:15:19 +00:00 · 42764d18c7
parent 63c475c600
commit 42764d18c7
1 changed files with 4 additions and 0 deletions
--- a/pytorch_lightning/trainer/trainer.py
+++ b/pytorch_lightning/trainer/trainer.py
@ -1156,6 +1156,10 @@ class Trainer(TrainerIO):
        except Exception:
            if type(output) is torch.Tensor:
                loss = output
+            else:
+                raise RuntimeError(
+                    'No `loss` value in the dictionary returned from `model.training_step()`.'
+                )

        # when using dp need to reduce the loss
        if self.use_dp: