Improve pytorch lightning examples

examples/frameworks/jsonargparse/pytorch_lightning_cli.yml

@@ -8,6 +8,6 @@ trainer:
         filename: best
         save_last: False
         save_top_k: 1
-        monitor: loss
+        monitor: train_loss
         mode: min
   max_epochs: 10

examples/frameworks/jsonargparse/pytorch_lightning_cli_old.py

@@ -78,6 +78,7 @@ class ImageClassifier(LightningModule):
         x, y = batch
         logits = self.forward(x)
         loss = F.nll_loss(logits, y.long())
+        self.log("train_loss", loss)
         return loss
 
     def test_step(self, batch, batch_idx):

examples/frameworks/jsonargparse/pytorch_lightning_cli_old.yml

@@ -8,5 +8,6 @@ trainer:
         filename: best
         save_last: False
         save_top_k: 1
-        monitor: loss
-        mode: min
+        monitor: train_loss
+        mode: min
+  max_epochs: 3