python - 使用 load_model 加载 tensorflow.keras 训练模型返回 JSON 解码错误,而未训练模型正常加载
问题描述
我有一个训练有素的 Keras 模型,使用 tensorflow.keras API 构建和训练,并使用tf.keras.save_model()
没有可选参数的方法保存。TensorFlow 是最新的,我的 Python 版本是 3.8。据我了解,这种方法应该使用 TF 2.X 中推荐的默认“tf”格式保存模型,然后使用load_model()
应该可以正常工作。
但是,再次加载模型会产生以下结果:
model = tf.keras.models.load_model("/Volumes/thesis_drive/thesis_project_local_new/trained_model_640x64/")
---------------------------------------------------------------------------
JSONDecodeError Traceback (most recent call last)
/var/folders/c1/8tq0t8y90195qxyt5hppjjtr0000gq/T/ipykernel_933/1131710361.py in <module>
----> 1 model = tf.keras.models.load_model("/Volumes/thesis_drive/thesis_project_local_new/trained_model_640x64/")
~/miniforge3/lib/python3.9/site-packages/tensorflow/python/keras/saving/save.py in load_model(filepath, custom_objects, compile, options)
204 filepath = path_to_string(filepath)
205 if isinstance(filepath, str):
--> 206 return saved_model_load.load(filepath, compile, options)
207
208 raise IOError(
~/miniforge3/lib/python3.9/site-packages/tensorflow/python/keras/saving/saved_model/load.py in load(path, compile, options)
153
154 # Finalize the loaded layers and remove the extra tracked dependencies.
--> 155 keras_loader.finalize_objects()
156 keras_loader.del_tracking()
157
~/miniforge3/lib/python3.9/site-packages/tensorflow/python/keras/saving/saved_model/load.py in finalize_objects(self)
624
625 # Initialize graph networks, now that layer dependencies have been resolved.
--> 626 self._reconstruct_all_models()
627
628 def _unblock_model_reconstruction(self, layer_id, layer):
~/miniforge3/lib/python3.9/site-packages/tensorflow/python/keras/saving/saved_model/load.py in _reconstruct_all_models(self)
643 all_initialized_models.add(model_id)
644 model, layers = self.model_layer_dependencies[model_id]
--> 645 self._reconstruct_model(model_id, model, layers)
646 _finalize_config_layers([model])
647
~/miniforge3/lib/python3.9/site-packages/tensorflow/python/keras/saving/saved_model/load.py in _reconstruct_model(self, model_id, model, layers)
659 def _reconstruct_model(self, model_id, model, layers):
660 """Reconstructs the network structure."""
--> 661 config = json_utils.decode(
662 self._proto.nodes[model_id].user_object.metadata)['config']
663
~/miniforge3/lib/python3.9/site-packages/tensorflow/python/keras/saving/saved_model/json_utils.py in decode(json_string)
60
61 def decode(json_string):
---> 62 return json.loads(json_string, object_hook=_decode_helper)
63
64
~/miniforge3/lib/python3.9/json/__init__.py in loads(s, cls, object_hook, parse_float, parse_int, parse_constant, object_pairs_hook, **kw)
357 if parse_constant is not None:
358 kw['parse_constant'] = parse_constant
--> 359 return cls(**kw).decode(s)
~/miniforge3/lib/python3.9/json/decoder.py in decode(self, s, _w)
335
336 """
--> 337 obj, end = self.raw_decode(s, idx=_w(s, 0).end())
338 end = _w(s, end).end()
339 if end != len(s):
~/miniforge3/lib/python3.9/json/decoder.py in raw_decode(self, s, idx)
353 obj, end = self.scan_once(s, idx)
354 except StopIteration as err:
--> 355 raise JSONDecodeError("Expecting value", s, err.value) from None
356 return obj, end
JSONDecodeError: Expecting value: line 1 column 1 (char 0)
为了测试这是否是save_model()
or的错误load_model()
,我在 Jupyter 笔记本中再次构建了相同的模型,保存它,然后重新加载它没有错误:
import tensorflow as tf
from tensorflow.keras.layers import Dense, Activation, Flatten, Dropout, Conv2D, MaxPooling2D, Input
from tensorflow.keras.losses import CategoricalCrossentropy
from tensorflow.keras import optimizers
from tensorflow.keras.models import Model
def build_model():
_input = Input(shape=(640,64,3))
x = Conv2D(filters=64, kernel_size=4, input_shape=(640, 64, 3))(_input)
x = Activation('relu')(x)
x = MaxPooling2D(pool_size=(4, 4))(x)
x = Dropout(0.5)(x)
x = Conv2D(filters=128, kernel_size=4, input_shape=(640, 64, 3))(_input)
x = Activation('relu')(x)
x = MaxPooling2D(pool_size=(4, 4))(x)
x = Dropout(0.5)(x)
x = Conv2D(filters=256, kernel_size=4, input_shape=(640, 64, 3))(_input)
x = Activation('relu')(x)
x = MaxPooling2D(pool_size=(2, 2))(x)
x = Dropout(0.5)(x)
x = Flatten()(x)
output = Dense(161, activation = 'softmax')(x)
model = Model(_input,output)
model.compile(optimizer=optimizers.Adam(), loss="categorical_crossentropy")
tf.keras.models.save_model(model,"model_test")
model = build_model()
Metal device set to: Apple M1
2021-09-23 13:40:46.234438: I tensorflow/core/common_runtime/pluggable_device/pluggable_device_factory.cc:305] Could not identify NUMA node of platform GPU ID 0, defaulting to 0. Your kernel may not have been built with NUMA support.
2021-09-23 13:40:46.234631: I tensorflow/core/common_runtime/pluggable_device/pluggable_device_factory.cc:271] Created TensorFlow device (/job:localhost/replica:0/task:0/device:GPU:0 with 0 MB memory) -> physical PluggableDevice (device: 0, name: METAL, pci bus id: <undefined>)
2021-09-23 13:40:47.112730: W tensorflow/python/util/util.cc:348] Sets are not currently considered sequences, but this may change in the future, so consider avoiding using them.
INFO:tensorflow:Assets written to: model_test/assets
del model
model = tf.keras.models.load_model("model_test")
更多细节:该模型是在另一台运行 Linux 的机器(我可以通过我的大学访问的超级计算机)上训练的,并通过 SCP 转移到我的 Apple M1 机器上,现在它出现了这个加载错误。
我不知道为什么要调用 JSON 模块 - 目录中的任何地方似乎都没有 JSON 文件。但是,鉴于在没有训练的情况下重建模型并加载它不会产生错误,我怀疑保存没有正确执行。
解决方案
tensorflow 2.3.1 面临同样的问题。更新到 2.7,现在它又可以工作了!
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