replace lazy with functools.lru_cache

deepmd/pt/train/training.py

@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: LGPL-3.0-or-later
+import functools
 import logging
 import time
 from copy import (
@@ -38,7 +39,6 @@
 from deepmd.pt.utils.dataloader import (
     BufferedIterator,
     get_weighted_sampler,
-    lazy,
 )
 from deepmd.pt.utils.env import (
     DEVICE,
@@ -214,7 +214,7 @@ def get_single_model(
                 _validation_data.add_data_requirement(_data_requirement)
             if not resuming:
 
-                @lazy
+                @functools.lru_cache
                 def get_sample():
                     sampled = make_stat_input(
                         _training_data.systems,

deepmd/pt/utils/dataloader.py

@@ -262,20 +262,3 @@ def get_weighted_sampler(training_data, prob_style, sys_prob=False):
     with torch.device("cpu"):
         sampler = WeightedRandomSampler(probs, len_sampler, replacement=True)
     return sampler
-
-
-class LazyFunction:
-    def __init__(self, func):
-        self.func = func
-        self.result = None
-        self.called = False
-
-    def __call__(self, *args, **kwargs):
-        if not self.called:
-            self.result = self.func(*args, **kwargs)
-            self.called = True
-        return self.result
-
-
-def lazy(func):
-    return LazyFunction(func)