From 4e0f5d5ec9e9eeb2e892740dd105a901556b134e Mon Sep 17 00:00:00 2001
From: Linlang <30293408+SunsetWolf@users.noreply.github.com>
Date: Wed, 21 Jan 2026 15:09:34 +0800
Subject: [PATCH] fix: use semantic version comparison for PyTorch scheduler
 compatibility (#2094)

---
 qlib/contrib/model/pytorch_nn.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/qlib/contrib/model/pytorch_nn.py b/qlib/contrib/model/pytorch_nn.py
index 190d1ba45..9f427bd94 100644
--- a/qlib/contrib/model/pytorch_nn.py
+++ b/qlib/contrib/model/pytorch_nn.py
@@ -10,6 +10,7 @@ import os
 import gc
 import numpy as np
 import pandas as pd
+from packaging import version
 from typing import Callable, Optional, Text, Union
 from sklearn.metrics import roc_auc_score, mean_squared_error
 
@@ -148,7 +149,7 @@ class DNNModelPytorch(Model):
         if scheduler == "default":
             # In torch version 2.7.0, the verbose parameter has been removed. Reference Link:
             # https://github.com/pytorch/pytorch/pull/147301/files#diff-036a7470d5307f13c9a6a51c3a65dd014f00ca02f476c545488cd856bea9bcf2L1313
-            if str(torch.__version__).split("+", maxsplit=1)[0] <= "2.6.0":
+            if version.parse(str(torch.__version__).split("+", maxsplit=1)[0]) <= version.parse("2.6.0"):
                 # Reduce learning rate when loss has stopped decrease
                 self.scheduler = torch.optim.lr_scheduler.ReduceLROnPlateau(  # pylint: disable=E1123
                     self.train_optimizer,