Making log more concise

Making the log parameters method more concise as suggested.

docs/userguide/torch_forecasting_models.md

@@ -512,33 +512,20 @@ with mlflow.start_run(nested=True) as run:
     # dataset is used for model training
     mlflow.log_input(dataset, context="training")
 
-    mlflow.log_param("model_type", "Darts_Pytorch_model")
-    mlflow.log_param("input_chunk_length", 24)
-    mlflow.log_param("output_chunk_length", 12)                   
-    mlflow.log_param("n_epochs", 500)
-    mlflow.log_param("model_name", 'NBEATS_MLflow')
-    mlflow.log_param("log_tensorboard", True)
-    mlflow.log_param("torch_metrics", "torchmetrics.regression.MeanAbsolutePercentageError()")
-    mlflow.log_param("nr_epochs_val_period", 1)
-    mlflow.log_param("pl_trainer_kwargs", "{callbacks: [loss_logger]}")    
-
-
-    from pytorch_lightning.callbacks import Callback
-
-    class LossLogger(Callback):
-        def __init__(self):
-            self.train_loss = []
-            self.val_loss = []
-
-        # will automatically be called at the end of each epoch
-        def on_train_epoch_end(self, trainer: "pl.Trainer", pl_module: "pl.LightningModule") -> None:
-            self.train_loss.append(float(trainer.callback_metrics["train_loss"]))
-
-        def on_validation_epoch_end(self, trainer: "pl.Trainer", pl_module: "pl.LightningModule") -> None:
-            self.val_loss.append(float(trainer.callback_metrics["val_loss"]))
-
-
-    loss_logger = LossLogger()    
+    # Define model hyperparameters to log
+    params = {
+              "model_type": "Darts_Pytorch_model",
+              "input_chunk_length": 24,
+              "output_chunk_length": 12,
+              "n_epochs": 500,
+              "model_name": "NBEATS_MLflow",
+              "log_tensorboard": True,
+              "torch_metrics": "torchmetrics.regression.MeanAbsolutePercentageError()",
+              "nr_epochs_val_period": 1,
+        }
+
+    # Log hyperparameters
+    mlflow.log_params(params)    
 
     # create the model
     model = NBEATSModel(
@@ -549,7 +536,7 @@ with mlflow.start_run(nested=True) as run:
         log_tensorboard=True,
         torch_metrics=torch_metrics,
         nr_epochs_val_period=1,
-        pl_trainer_kwargs={"callbacks": [loss_logger]})
+        )
 
     # use validation dataset
     model.fit(