Fixed loading of learning rate

src/ptbench/engine/callbacks.py

@@ -46,7 +46,7 @@ class LoggingCallback(Callback):
         self.log("total_time", current_time)
         self.log("eta", eta_seconds)
         self.log("loss", numpy.average(self.training_loss))
-        self.log("learning_rate", pl_module.lr)
+        self.log("learning_rate", pl_module.hparams["optimizer_params"]["lr"])
         self.log("validation_loss", numpy.average(self.validation_loss))
 
         queue_retries = 0