应该定义密集层输入的最后一个维度。找到 None。收到完整的输入形状：<unknown>
The last dimension of the inputs to a Dense layer should be defined. Found None. Full input shape received: <unknown>
我在将模型从一些本地虚拟数据切换到使用 TF 数据集时遇到问题。
抱歉模型代码太长了，我已经尽量缩短了。
以下工作正常：
import tensorflow as tf
import tensorflow_recommenders as tfrs
from transformers import AutoTokenizer, TFAutoModel
MODEL_PATH = 'sentence-transformers/all-MiniLM-L6-v2'
tokenizer = AutoTokenizer.from_pretrained(MODEL_PATH)
model = TFAutoModel.from_pretrained(MODEL_PATH, from_pt=True)
class SBert(tf.keras.layers.Layer):
def __init__(self, tokenizer, model):
super(SBert, self).__init__()
self.tokenizer = tokenizer
self.model = model
def tf_encode(self, inputs):
def encode(inputs):
inputs = [x[0].decode("utf-8") for x in inputs.numpy()]
outputs = self.tokenizer(inputs, padding=True, truncation=True, return_tensors='tf')
return outputs['input_ids'], outputs['token_type_ids'], outputs['attention_mask']
return tf.py_function(func=encode, inp=[inputs], Tout=[tf.int32, tf.int32, tf.int32])
def process(self, i, t, a):
def __call(i, t, a):
model_output = self.model(
{'input_ids': i.numpy(), 'token_type_ids': t.numpy(), 'attention_mask': a.numpy()}
)
return model_output[0]
return tf.py_function(func=__call, inp=[i, t, a], Tout=[tf.float32])
def mean_pooling(self, model_output, attention_mask):
token_embeddings = tf.squeeze(tf.stack(model_output), axis=0)
input_mask_expanded = tf.cast(
tf.broadcast_to(tf.expand_dims(attention_mask, -1), tf.shape(token_embeddings)),
tf.float32
)
a = tf.math.reduce_sum(token_embeddings * input_mask_expanded, axis=1)
b = tf.clip_by_value(tf.math.reduce_sum(input_mask_expanded, axis=1), 1e-9, tf.float32.max)
embeddings = a / b
embeddings, _ = tf.linalg.normalize(embeddings, 2, axis=1)
return embeddings
def call(self, inputs):
input_ids, token_type_ids, attention_mask = self.tf_encode(inputs)
model_output = self.process(input_ids, token_type_ids, attention_mask)
embeddings = self.mean_pooling(model_output, attention_mask)
return embeddings
sbert = SBert(tokenizer, model)
inputs = tf.keras.layers.Input(shape=(1,), dtype=tf.string)
outputs = sbert(inputs)
model = tf.keras.Model(inputs, outputs)
model(tf.constant(['some text', 'more text']))
对模型的调用输出张量 - yipee :)
现在我想在更大的双塔模型中使用这一层：
class Encoder(tf.keras.Model):
def __init__(self):
super().__init__()
self.text_embedding = self._build_text_embedding()
def _build_text_embedding(self):
sbert = SBert(tokenizer, model)
inputs = tf.keras.layers.Input(shape=(1,), dtype=tf.string)
outputs = sbert(inputs)
return tf.keras.Model(inputs, outputs)
def call(self, inputs):
return self.text_embedding(inputs)
class RecModel(tfrs.models.Model):
def __init__(self):
super().__init__()
self.query_model = tf.keras.Sequential([
Encoder(),
tf.keras.layers.Dense(32)
])
self.candidate_model = tf.keras.Sequential([
Encoder(),
tf.keras.layers.Dense(32)
])
self.retrieval_task = tfrs.tasks.Retrieval(
metrics=tfrs.metrics.FactorizedTopK(
candidates=tf.data.Dataset.from_tensor_slices(
data['text']
).batch(1).map(self.candidate_model),
),
batch_metrics=[
tf.keras.metrics.TopKCategoricalAccuracy(k=5)
]
)
def call(self, features):
query_embeddings = self.query_model(features['query'])
candidate_embeddings = self.candidate_model(features['text'])
return (
query_embeddings,
candidate_embeddings,
)
def compute_loss(self, features, training=False):
query_embeddings, candidate_embeddings = self(features)
retrieval_loss = self.retrieval_task(query_embeddings, candidate_embeddings)
return retrieval_loss
创建一个小的虚拟数据集：
data = {
'query': ['blue', 'cat', 'football'],
'text': ['a nice colour', 'a type of animal', 'a sport']
}
ds = tf.data.Dataset.from_tensor_slices(data).batch(1)
尝试编译：
model = RecModel()
model.compile(optimizer=tf.keras.optimizers.Adagrad())
我们遇到了以下错误：
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
<ipython-input-11-df4cc46e0307> in <module>
----> 1 model = RecModel()
2 model.compile(optimizer=tf.keras.optimizers.Adagrad())
<ipython-input-8-a774041744b9> in __init__(self)
33 candidates=tf.data.Dataset.from_tensor_slices(
34 data['text']
---> 35 ).batch(1).map(self.candidate_model),
36 ),
37 batch_metrics=[
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/data/ops/dataset_ops.py in map(self, map_func, num_parallel_calls, deterministic, name)
2014 warnings.warn("The `deterministic` argument has no effect unless the "
2015 "`num_parallel_calls` argument is specified.")
-> 2016 return MapDataset(self, map_func, preserve_cardinality=True, name=name)
2017 else:
2018 return ParallelMapDataset(
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/data/ops/dataset_ops.py in __init__(self, input_dataset, map_func, use_inter_op_parallelism, preserve_cardinality, use_legacy_function, name)
5193 self._transformation_name(),
5194 dataset=input_dataset,
-> 5195 use_legacy_function=use_legacy_function)
5196 self._metadata = dataset_metadata_pb2.Metadata()
5197 if name:
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/data/ops/structured_function.py in __init__(self, func, transformation_name, dataset, input_classes, input_shapes, input_types, input_structure, add_to_graph, use_legacy_function, defun_kwargs)
269 fn_factory = trace_tf_function(defun_kwargs)
270
--> 271 self._function = fn_factory()
272 # There is no graph to add in eager mode.
273 add_to_graph &= not context.executing_eagerly()
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/eager/function.py in get_concrete_function(self, *args, **kwargs)
3069 """
3070 graph_function = self._get_concrete_function_garbage_collected(
-> 3071 *args, **kwargs)
3072 graph_function._garbage_collector.release() # pylint: disable=protected-access
3073 return graph_function
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/eager/function.py in _get_concrete_function_garbage_collected(self, *args, **kwargs)
3034 args, kwargs = None, None
3035 with self._lock:
-> 3036 graph_function, _ = self._maybe_define_function(args, kwargs)
3037 seen_names = set()
3038 captured = object_identity.ObjectIdentitySet(
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/eager/function.py in _maybe_define_function(self, args, kwargs)
3290
3291 self._function_cache.add_call_context(cache_key.call_context)
-> 3292 graph_function = self._create_graph_function(args, kwargs)
3293 self._function_cache.add(cache_key, cache_key_deletion_observer,
3294 graph_function)
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/eager/function.py in _create_graph_function(self, args, kwargs, override_flat_arg_shapes)
3138 arg_names=arg_names,
3139 override_flat_arg_shapes=override_flat_arg_shapes,
-> 3140 capture_by_value=self._capture_by_value),
3141 self._function_attributes,
3142 function_spec=self.function_spec,
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/framework/func_graph.py in func_graph_from_py_func(name, python_func, args, kwargs, signature, func_graph, autograph, autograph_options, add_control_dependencies, arg_names, op_return_value, collections, capture_by_value, override_flat_arg_shapes, acd_record_initial_resource_uses)
1159 _, original_func = tf_decorator.unwrap(python_func)
1160
-> 1161 func_outputs = python_func(*func_args, **func_kwargs)
1162
1163 # invariant: `func_outputs` contains only Tensors, CompositeTensors,
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/data/ops/structured_function.py in wrapped_fn(*args)
246 attributes=defun_kwargs)
247 def wrapped_fn(*args): # pylint: disable=missing-docstring
--> 248 ret = wrapper_helper(*args)
249 ret = structure.to_tensor_list(self._output_structure, ret)
250 return [ops.convert_to_tensor(t) for t in ret]
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/data/ops/structured_function.py in wrapper_helper(*args)
175 if not _should_unpack(nested_args):
176 nested_args = (nested_args,)
--> 177 ret = autograph.tf_convert(self._func, ag_ctx)(*nested_args)
178 if _should_pack(ret):
179 ret = tuple(ret)
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/autograph/impl/api.py in wrapper(*args, **kwargs)
687 try:
688 with conversion_ctx:
--> 689 return converted_call(f, args, kwargs, options=options)
690 except Exception as e: # pylint:disable=broad-except
691 if hasattr(e, 'ag_error_metadata'):
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/autograph/impl/api.py in converted_call(f, args, kwargs, caller_fn_scope, options)
375
376 if not options.user_requested and conversion.is_allowlisted(f):
--> 377 return _call_unconverted(f, args, kwargs, options)
378
379 # internal_convert_user_code is for example turned off when issuing a dynamic
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/autograph/impl/api.py in _call_unconverted(f, args, kwargs, options, update_cache)
456
457 if kwargs is not None:
--> 458 return f(*args, **kwargs)
459 return f(*args)
460
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/keras/utils/traceback_utils.py in error_handler(*args, **kwargs)
65 except Exception as e: # pylint: disable=broad-except
66 filtered_tb = _process_traceback_frames(e.__traceback__)
---> 67 raise e.with_traceback(filtered_tb) from None
68 finally:
69 del filtered_tb
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/keras/layers/core/dense.py in build(self, input_shape)
137 last_dim = tf.compat.dimension_value(input_shape[-1])
138 if last_dim is None:
--> 139 raise ValueError('The last dimension of the inputs to a Dense layer '
140 'should be defined. Found None. '
141 f'Full input shape received: {input_shape}')
ValueError: Exception encountered when calling layer "sequential_5" (type Sequential).
The last dimension of the inputs to a Dense layer should be defined. Found None. Full input shape received: <unknown>
Call arguments received:
• inputs=tf.Tensor(shape=(None,), dtype=string)
• training=None
• mask=None
我不太确定应该在哪里设置形状 - 因为使用常规张量而不是 TF 数据集可以正常工作。
您必须明确设置来自 tf.py_functions 的张量的形状。使用 None 将允许可变输入长度。然而，Bert 输出维度 (384,) 是必需的：
import tensorflow as tf
from transformers import AutoTokenizer, TFAutoModel
MODEL_PATH = 'sentence-transformers/all-MiniLM-L6-v2'
tokenizer = AutoTokenizer.from_pretrained(MODEL_PATH)
model = TFAutoModel.from_pretrained(MODEL_PATH, from_pt=True)
class SBert(tf.keras.layers.Layer):
def __init__(self, tokenizer, model):
super(SBert, self).__init__()
self.tokenizer = tokenizer
self.model = model
def tf_encode(self, inputs):
def encode(inputs):
inputs = [x[0].decode("utf-8") for x in inputs.numpy()]
outputs = self.tokenizer(inputs, padding=True, truncation=True, return_tensors='tf')
return outputs['input_ids'], outputs['token_type_ids'], outputs['attention_mask']
return tf.py_function(func=encode, inp=[inputs], Tout=[tf.int32, tf.int32, tf.int32])
def process(self, i, t, a):
def __call(i, t, a):
model_output = self.model({'input_ids': i.numpy(), 'token_type_ids': t.numpy(), 'attention_mask': a.numpy()})
return model_output[0]
return tf.py_function(func=__call, inp=[i, t, a], Tout=[tf.float32])
def mean_pooling(self, model_output, attention_mask):
token_embeddings = tf.squeeze(tf.stack(model_output), axis=0)
input_mask_expanded = tf.cast(
tf.broadcast_to(tf.expand_dims(attention_mask, -1), tf.shape(token_embeddings)),
tf.float32
)
a = tf.math.reduce_sum(token_embeddings * input_mask_expanded, axis=1)
b = tf.clip_by_value(tf.math.reduce_sum(input_mask_expanded, axis=1), 1e-9, tf.float32.max)
embeddings = a / b
embeddings, _ = tf.linalg.normalize(embeddings, 2, axis=1)
return embeddings
def call(self, inputs):
input_ids, token_type_ids, attention_mask = self.tf_encode(inputs)
input_ids.set_shape(tf.TensorShape((None, None)))
token_type_ids.set_shape(tf.TensorShape((None, None)))
attention_mask.set_shape(tf.TensorShape((None, None)))
model_output = self.process(input_ids, token_type_ids, attention_mask)
model_output[0].set_shape(tf.TensorShape((None, None, 384)))
embeddings = self.mean_pooling(model_output, attention_mask)
return embeddings
sbert = SBert(tokenizer, model)
inputs = tf.keras.layers.Input((1,), dtype=tf.string)
outputs = sbert(inputs)
outputs = tf.keras.layers.Dense(32)(outputs)
model = tf.keras.Model(inputs, outputs)
print(model(tf.constant(['some text', 'more text'])))
print(model.summary())
tf.Tensor(
[[-0.06719425 -0.02954631 -0.05811356 -0.1456391 -0.13001677 0.00145465
0.0401044 0.05949172 -0.02589339 0.07255618 -0.00958113 0.01159782
0.02508018 0.03075579 -0.01910635 -0.03231853 0.00875124 0.01143366
-0.04365401 -0.02090197 0.07030752 -0.02872834 0.10535908 0.05691438
-0.017165 -0.02044982 0.02580127 -0.04564123 -0.0631128 -0.00303708
0.00133517 0.01613527]
[-0.11922387 0.02304137 -0.02670465 -0.13117084 -0.11492493 0.03961402
0.08129141 -0.05999354 0.0039564 0.02892766 0.00493046 0.00440936
-0.07966737 0.11354238 0.03141225 0.00048972 0.04658606 -0.03658888
-0.05292419 -0.04639702 0.08445395 0.00522146 0.04359548 0.0290177
-0.02171512 -0.03399373 -0.00418095 -0.04019783 -0.04733383 -0.03972956
0.01890458 -0.03927581]], shape=(2, 32), dtype=float32)
Model: "model_12"
_________________________________________________________________
Layer (type) Output Shape Param #
=================================================================
input_18 (InputLayer) [(None, 1)] 0
s_bert_17 (SBert) (None, 384) 22713216
dense_78 (Dense) (None, 32) 12320
=================================================================
Total params: 22,725,536
Trainable params: 22,725,536
Non-trainable params: 0
_________________________________________________________________
None
我在将模型从一些本地虚拟数据切换到使用 TF 数据集时遇到问题。
抱歉模型代码太长了，我已经尽量缩短了。
以下工作正常：
import tensorflow as tf
import tensorflow_recommenders as tfrs
from transformers import AutoTokenizer, TFAutoModel
MODEL_PATH = 'sentence-transformers/all-MiniLM-L6-v2'
tokenizer = AutoTokenizer.from_pretrained(MODEL_PATH)
model = TFAutoModel.from_pretrained(MODEL_PATH, from_pt=True)
class SBert(tf.keras.layers.Layer):
def __init__(self, tokenizer, model):
super(SBert, self).__init__()
self.tokenizer = tokenizer
self.model = model
def tf_encode(self, inputs):
def encode(inputs):
inputs = [x[0].decode("utf-8") for x in inputs.numpy()]
outputs = self.tokenizer(inputs, padding=True, truncation=True, return_tensors='tf')
return outputs['input_ids'], outputs['token_type_ids'], outputs['attention_mask']
return tf.py_function(func=encode, inp=[inputs], Tout=[tf.int32, tf.int32, tf.int32])
def process(self, i, t, a):
def __call(i, t, a):
model_output = self.model(
{'input_ids': i.numpy(), 'token_type_ids': t.numpy(), 'attention_mask': a.numpy()}
)
return model_output[0]
return tf.py_function(func=__call, inp=[i, t, a], Tout=[tf.float32])
def mean_pooling(self, model_output, attention_mask):
token_embeddings = tf.squeeze(tf.stack(model_output), axis=0)
input_mask_expanded = tf.cast(
tf.broadcast_to(tf.expand_dims(attention_mask, -1), tf.shape(token_embeddings)),
tf.float32
)
a = tf.math.reduce_sum(token_embeddings * input_mask_expanded, axis=1)
b = tf.clip_by_value(tf.math.reduce_sum(input_mask_expanded, axis=1), 1e-9, tf.float32.max)
embeddings = a / b
embeddings, _ = tf.linalg.normalize(embeddings, 2, axis=1)
return embeddings
def call(self, inputs):
input_ids, token_type_ids, attention_mask = self.tf_encode(inputs)
model_output = self.process(input_ids, token_type_ids, attention_mask)
embeddings = self.mean_pooling(model_output, attention_mask)
return embeddings
sbert = SBert(tokenizer, model)
inputs = tf.keras.layers.Input(shape=(1,), dtype=tf.string)
outputs = sbert(inputs)
model = tf.keras.Model(inputs, outputs)
model(tf.constant(['some text', 'more text']))
对模型的调用输出张量 - yipee :)
现在我想在更大的双塔模型中使用这一层：
class Encoder(tf.keras.Model):
def __init__(self):
super().__init__()
self.text_embedding = self._build_text_embedding()
def _build_text_embedding(self):
sbert = SBert(tokenizer, model)
inputs = tf.keras.layers.Input(shape=(1,), dtype=tf.string)
outputs = sbert(inputs)
return tf.keras.Model(inputs, outputs)
def call(self, inputs):
return self.text_embedding(inputs)
class RecModel(tfrs.models.Model):
def __init__(self):
super().__init__()
self.query_model = tf.keras.Sequential([
Encoder(),
tf.keras.layers.Dense(32)
])
self.candidate_model = tf.keras.Sequential([
Encoder(),
tf.keras.layers.Dense(32)
])
self.retrieval_task = tfrs.tasks.Retrieval(
metrics=tfrs.metrics.FactorizedTopK(
candidates=tf.data.Dataset.from_tensor_slices(
data['text']
).batch(1).map(self.candidate_model),
),
batch_metrics=[
tf.keras.metrics.TopKCategoricalAccuracy(k=5)
]
)
def call(self, features):
query_embeddings = self.query_model(features['query'])
candidate_embeddings = self.candidate_model(features['text'])
return (
query_embeddings,
candidate_embeddings,
)
def compute_loss(self, features, training=False):
query_embeddings, candidate_embeddings = self(features)
retrieval_loss = self.retrieval_task(query_embeddings, candidate_embeddings)
return retrieval_loss
创建一个小的虚拟数据集：
data = {
'query': ['blue', 'cat', 'football'],
'text': ['a nice colour', 'a type of animal', 'a sport']
}
ds = tf.data.Dataset.from_tensor_slices(data).batch(1)
尝试编译：
model = RecModel()
model.compile(optimizer=tf.keras.optimizers.Adagrad())
我们遇到了以下错误：
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
<ipython-input-11-df4cc46e0307> in <module>
----> 1 model = RecModel()
2 model.compile(optimizer=tf.keras.optimizers.Adagrad())
<ipython-input-8-a774041744b9> in __init__(self)
33 candidates=tf.data.Dataset.from_tensor_slices(
34 data['text']
---> 35 ).batch(1).map(self.candidate_model),
36 ),
37 batch_metrics=[
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/data/ops/dataset_ops.py in map(self, map_func, num_parallel_calls, deterministic, name)
2014 warnings.warn("The `deterministic` argument has no effect unless the "
2015 "`num_parallel_calls` argument is specified.")
-> 2016 return MapDataset(self, map_func, preserve_cardinality=True, name=name)
2017 else:
2018 return ParallelMapDataset(
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/data/ops/dataset_ops.py in __init__(self, input_dataset, map_func, use_inter_op_parallelism, preserve_cardinality, use_legacy_function, name)
5193 self._transformation_name(),
5194 dataset=input_dataset,
-> 5195 use_legacy_function=use_legacy_function)
5196 self._metadata = dataset_metadata_pb2.Metadata()
5197 if name:
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/data/ops/structured_function.py in __init__(self, func, transformation_name, dataset, input_classes, input_shapes, input_types, input_structure, add_to_graph, use_legacy_function, defun_kwargs)
269 fn_factory = trace_tf_function(defun_kwargs)
270
--> 271 self._function = fn_factory()
272 # There is no graph to add in eager mode.
273 add_to_graph &= not context.executing_eagerly()
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/eager/function.py in get_concrete_function(self, *args, **kwargs)
3069 """
3070 graph_function = self._get_concrete_function_garbage_collected(
-> 3071 *args, **kwargs)
3072 graph_function._garbage_collector.release() # pylint: disable=protected-access
3073 return graph_function
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/eager/function.py in _get_concrete_function_garbage_collected(self, *args, **kwargs)
3034 args, kwargs = None, None
3035 with self._lock:
-> 3036 graph_function, _ = self._maybe_define_function(args, kwargs)
3037 seen_names = set()
3038 captured = object_identity.ObjectIdentitySet(
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/eager/function.py in _maybe_define_function(self, args, kwargs)
3290
3291 self._function_cache.add_call_context(cache_key.call_context)
-> 3292 graph_function = self._create_graph_function(args, kwargs)
3293 self._function_cache.add(cache_key, cache_key_deletion_observer,
3294 graph_function)
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/eager/function.py in _create_graph_function(self, args, kwargs, override_flat_arg_shapes)
3138 arg_names=arg_names,
3139 override_flat_arg_shapes=override_flat_arg_shapes,
-> 3140 capture_by_value=self._capture_by_value),
3141 self._function_attributes,
3142 function_spec=self.function_spec,
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/framework/func_graph.py in func_graph_from_py_func(name, python_func, args, kwargs, signature, func_graph, autograph, autograph_options, add_control_dependencies, arg_names, op_return_value, collections, capture_by_value, override_flat_arg_shapes, acd_record_initial_resource_uses)
1159 _, original_func = tf_decorator.unwrap(python_func)
1160
-> 1161 func_outputs = python_func(*func_args, **func_kwargs)
1162
1163 # invariant: `func_outputs` contains only Tensors, CompositeTensors,
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/data/ops/structured_function.py in wrapped_fn(*args)
246 attributes=defun_kwargs)
247 def wrapped_fn(*args): # pylint: disable=missing-docstring
--> 248 ret = wrapper_helper(*args)
249 ret = structure.to_tensor_list(self._output_structure, ret)
250 return [ops.convert_to_tensor(t) for t in ret]
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/data/ops/structured_function.py in wrapper_helper(*args)
175 if not _should_unpack(nested_args):
176 nested_args = (nested_args,)
--> 177 ret = autograph.tf_convert(self._func, ag_ctx)(*nested_args)
178 if _should_pack(ret):
179 ret = tuple(ret)
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/autograph/impl/api.py in wrapper(*args, **kwargs)
687 try:
688 with conversion_ctx:
--> 689 return converted_call(f, args, kwargs, options=options)
690 except Exception as e: # pylint:disable=broad-except
691 if hasattr(e, 'ag_error_metadata'):
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/autograph/impl/api.py in converted_call(f, args, kwargs, caller_fn_scope, options)
375
376 if not options.user_requested and conversion.is_allowlisted(f):
--> 377 return _call_unconverted(f, args, kwargs, options)
378
379 # internal_convert_user_code is for example turned off when issuing a dynamic
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/tensorflow/python/autograph/impl/api.py in _call_unconverted(f, args, kwargs, options, update_cache)
456
457 if kwargs is not None:
--> 458 return f(*args, **kwargs)
459 return f(*args)
460
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/keras/utils/traceback_utils.py in error_handler(*args, **kwargs)
65 except Exception as e: # pylint: disable=broad-except
66 filtered_tb = _process_traceback_frames(e.__traceback__)
---> 67 raise e.with_traceback(filtered_tb) from None
68 finally:
69 del filtered_tb
~/.pyenv/versions/3.7.8/lib/python3.7/site-packages/keras/layers/core/dense.py in build(self, input_shape)
137 last_dim = tf.compat.dimension_value(input_shape[-1])
138 if last_dim is None:
--> 139 raise ValueError('The last dimension of the inputs to a Dense layer '
140 'should be defined. Found None. '
141 f'Full input shape received: {input_shape}')
ValueError: Exception encountered when calling layer "sequential_5" (type Sequential).
The last dimension of the inputs to a Dense layer should be defined. Found None. Full input shape received: <unknown>
Call arguments received:
• inputs=tf.Tensor(shape=(None,), dtype=string)
• training=None
• mask=None
我不太确定应该在哪里设置形状 - 因为使用常规张量而不是 TF 数据集可以正常工作。
您必须明确设置来自 tf.py_functions 的张量的形状。使用 None 将允许可变输入长度。然而，Bert 输出维度 (384,) 是必需的：
import tensorflow as tf
from transformers import AutoTokenizer, TFAutoModel
MODEL_PATH = 'sentence-transformers/all-MiniLM-L6-v2'
tokenizer = AutoTokenizer.from_pretrained(MODEL_PATH)
model = TFAutoModel.from_pretrained(MODEL_PATH, from_pt=True)
class SBert(tf.keras.layers.Layer):
def __init__(self, tokenizer, model):
super(SBert, self).__init__()
self.tokenizer = tokenizer
self.model = model
def tf_encode(self, inputs):
def encode(inputs):
inputs = [x[0].decode("utf-8") for x in inputs.numpy()]
outputs = self.tokenizer(inputs, padding=True, truncation=True, return_tensors='tf')
return outputs['input_ids'], outputs['token_type_ids'], outputs['attention_mask']
return tf.py_function(func=encode, inp=[inputs], Tout=[tf.int32, tf.int32, tf.int32])
def process(self, i, t, a):
def __call(i, t, a):
model_output = self.model({'input_ids': i.numpy(), 'token_type_ids': t.numpy(), 'attention_mask': a.numpy()})
return model_output[0]
return tf.py_function(func=__call, inp=[i, t, a], Tout=[tf.float32])
def mean_pooling(self, model_output, attention_mask):
token_embeddings = tf.squeeze(tf.stack(model_output), axis=0)
input_mask_expanded = tf.cast(
tf.broadcast_to(tf.expand_dims(attention_mask, -1), tf.shape(token_embeddings)),
tf.float32
)
a = tf.math.reduce_sum(token_embeddings * input_mask_expanded, axis=1)
b = tf.clip_by_value(tf.math.reduce_sum(input_mask_expanded, axis=1), 1e-9, tf.float32.max)
embeddings = a / b
embeddings, _ = tf.linalg.normalize(embeddings, 2, axis=1)
return embeddings
def call(self, inputs):
input_ids, token_type_ids, attention_mask = self.tf_encode(inputs)
input_ids.set_shape(tf.TensorShape((None, None)))
token_type_ids.set_shape(tf.TensorShape((None, None)))
attention_mask.set_shape(tf.TensorShape((None, None)))
model_output = self.process(input_ids, token_type_ids, attention_mask)
model_output[0].set_shape(tf.TensorShape((None, None, 384)))
embeddings = self.mean_pooling(model_output, attention_mask)
return embeddings
sbert = SBert(tokenizer, model)
inputs = tf.keras.layers.Input((1,), dtype=tf.string)
outputs = sbert(inputs)
outputs = tf.keras.layers.Dense(32)(outputs)
model = tf.keras.Model(inputs, outputs)
print(model(tf.constant(['some text', 'more text'])))
print(model.summary())
tf.Tensor(
[[-0.06719425 -0.02954631 -0.05811356 -0.1456391 -0.13001677 0.00145465
0.0401044 0.05949172 -0.02589339 0.07255618 -0.00958113 0.01159782
0.02508018 0.03075579 -0.01910635 -0.03231853 0.00875124 0.01143366
-0.04365401 -0.02090197 0.07030752 -0.02872834 0.10535908 0.05691438
-0.017165 -0.02044982 0.02580127 -0.04564123 -0.0631128 -0.00303708
0.00133517 0.01613527]
[-0.11922387 0.02304137 -0.02670465 -0.13117084 -0.11492493 0.03961402
0.08129141 -0.05999354 0.0039564 0.02892766 0.00493046 0.00440936
-0.07966737 0.11354238 0.03141225 0.00048972 0.04658606 -0.03658888
-0.05292419 -0.04639702 0.08445395 0.00522146 0.04359548 0.0290177
-0.02171512 -0.03399373 -0.00418095 -0.04019783 -0.04733383 -0.03972956
0.01890458 -0.03927581]], shape=(2, 32), dtype=float32)
Model: "model_12"
_________________________________________________________________
Layer (type) Output Shape Param #
=================================================================
input_18 (InputLayer) [(None, 1)] 0
s_bert_17 (SBert) (None, 384) 22713216
dense_78 (Dense) (None, 32) 12320
=================================================================
Total params: 22,725,536
Trainable params: 22,725,536
Non-trainable params: 0
_________________________________________________________________
None