Develop Reference

Keras Concatenate and Lambda not recognized as Layer, TypeError: The added layer must be an instance of class Layer

I have been unable to find a solution for my problem. The below (with and without Lambda) does not recognize the result of Concatenate as a Layer:
tensors = []
for item in items:
tensor = tf.constant(item, dtype=tf.string, shape=[1])
tensors.append(tensor)
def constant_layer(tensor):
return tf.keras.layers.Input(tensor=tensor, shape=tensor.shape)
input_layers = []
for tensor in tensors:
input_layers.append(constant_layer(tensor))
model = tf.keras.Sequential()
model.add(tf.keras.layers.Lambda(lambda x: tf.keras.layers.Concatenate()(x))(input_layers))
model.add(tf.keras.layers.Dense(10, activation='relu'))
model.add(tf.keras.layers.Dense(10, activation='relu'))
model.add(tf.keras.layers.Dense(1))
# Compile model
model.compile(optimizer='adam', loss='mean_squared_error')
The error I receive is the following:
File "script.py", line 25
model.add(tf.keras.layers.Lambda(lambda x: tf.keras.layers.Concatenate()(x))(input_layers))
File "./lib/python3.7/site-packages/tensorflow/python/trackable/base.py", line 205, in _method_wrapper
result = method(self, *args, **kwargs)
File "./lib/python3.7/site-packages/keras/utils/traceback_utils.py", line 70, in error_handler
raise e.with_traceback(filtered_tb) from None
File "./lib/python3.7/site-packages/keras/engine/sequential.py", line 187, in add
"The added layer must be an instance of class Layer. "
TypeError: The added layer must be an instance of class Layer. Received: layer=KerasTensor(type_spec=TensorSpec(shape=(1,), dtype=tf.string, name=None), name='lambda/concatenate/concat/concat:0', description="created by layer 'lambda'") of type <class 'keras.engine.keras_tensor.KerasTensor'>.
I'm trying to apply TF variables to the model, the input is a list of strings. Any suggestions?

The workaround that fixed it for me was to add the result of the concatenation to an Input layer, the following succeeded for me:
concat_layer = tf.keras.layers.Concatenate()(tensors)
reshape_layer = tf.keras.layers.Reshape((1,))(concat_layer)
input_layer = tf.keras.layers.Input(tensor=reshape_layer, shape=reshape_layer.shape, dtype=tf.string)
model = tf.keras.Sequential()
model.add(input_layer)
model.add(tf.keras.layers.Dense(10, activation='relu'))
model.add(tf.keras.layers.Dense(10, activation='relu'))
model.add(tf.keras.layers.Dense(1))
...

Tensorflow TypeError: Can not convert a NoneType into a Tensor or Operation

I am learning TensorFlow and was going through this step-by-step guide. The below code is the exact same as on the website. However, when running it, I get an error when trying to fit the model. The full traceback I get is as follows:
Traceback (most recent call last):
File "C:\users\name\desktop\python ml tutorial\embedding.py", line 49, in <module>
model.fit(x=padded_docs, y=labels, epochs=50, verbose=0)
File "C:\Users\name\AppData\Local\Programs\Python\Python37\lib\site-packages\keras\engine\training.py", line 1213, in fit
self._make_train_function()
File "C:\Users\name\AppData\Local\Programs\Python\Python37\lib\site-packages\keras\engine\training.py", line 316, in _make_train_function
loss=self.total_loss)
File "C:\Users\name\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\optimizer_v2\optimizer_v2.py", line 506, in get_updates
return [self.apply_gradients(grads_and_vars)]
File "C:\Users\name\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\optimizer_v2\optimizer_v2.py", line 441, in apply_gradients
kwargs={"name": name})
File "C:\Users\name\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\distribute\distribute_lib.py", line 1917, in merge_call
return self._merge_call(merge_fn, args, kwargs)
File "C:\Users\name\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\distribute\distribute_lib.py", line 1924, in _merge_call
return merge_fn(self._strategy, *args, **kwargs)
File "C:\Users\name\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\optimizer_v2\optimizer_v2.py", line 494, in _distributed_apply
with ops.control_dependencies(update_ops):
File "C:\Users\name\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\framework\ops.py", line 5257, in control_dependencies
return get_default_graph().control_dependencies(control_inputs)
File "C:\Users\name\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\framework\func_graph.py", line 356, in control_dependencies
return super(FuncGraph, self).control_dependencies(filtered_control_inputs)
File "C:\Users\name\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\framework\ops.py", line 4691, in control_dependencies
c = self.as_graph_element(c)
File "C:\Users\name\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\framework\ops.py", line 3610, in as_graph_element
return self._as_graph_element_locked(obj, allow_tensor, allow_operation)
File "C:\Users\name\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\framework\ops.py", line 3699, in _as_graph_element_locked
(type(obj).__name__, types_str))
TypeError: Can not convert a NoneType into a Tensor or Operation.
And the full code is below:
from numpy import array
from keras.preprocessing.text import one_hot
from keras.preprocessing.sequence import pad_sequences
from keras.models import Sequential
from keras.layers import Dense
from keras.layers import Flatten
from keras.layers.embeddings import Embedding
# define document
docs = ['Well done!',
'Good work',
'Great effort',
'nice work',
'Excellent!',
'Weak',
'Poor effort!',
'not good',
'poor work',
'Could have done better.']
# define class labels
labels = array([1,1,1,1,1,0,0,0,0,0])
# integer-encode the documents
vocab_size = 50
encoded_docs = [one_hot(d, vocab_size) for d in docs]
print(encoded_docs)
# padding
max_length = 4
padded_docs = pad_sequences(encoded_docs, maxlen = max_length, padding = 'post')
print(padded_docs)
# define model
model = Sequential()
model.add(Embedding(vocab_size, 8, input_length=max_length))
model.add(Flatten())
model.add(Dense(1, activation='sigmoid'))
# compile the model
model.compile(optimizer = 'adam', loss = 'binary_crossentropy', metrics=['accuracy'])
# summarize
print(model.summary())
# fit the model
model.fit(x=padded_docs, y=labels, epochs=50, verbose=0)
# evaluate the model
loss, accuracy = model.evaluate(x=padded_docs, y=labels, verbose=0)
print("Accuracy: {}".format(accuracy))
What's going on here? The article was originally written back in 2017 but its last revision and update was just a week ago. I imagine they are constantly tweaking TensorFlow since it is still state-of-the-art and needs a lot of improvement.
Any ideas on how to circumvent this?
Edit:
I began trying to figure out where the script could have gone wrong. I will be listing what I found here, hopefully it will help us spot something:
I found that in ops.py's control_dependencies() function, control_inputs parameter has the following values: Tensor("Adam/gradients/gradients/loss/dense_1_loss/binary_crossentropy/logistic_loss_grad/Reshape_1:0", shape=(None, 1), dtype=float32), Tensor("Adam/gradients/gradients/loss/dense_1_loss/binary_crossentropy/logistic_loss/Log1p_grad/mul:0", shape=(None, 1), dtype=float32), and None. When it becomes None, the program crashes.

ValueError: Passing a dictionary input to a Sequential Model which doesn't have FeatureLayer as the first layer is an error

I've tried running the following code, but got this error:
File
"C:\Users\TomerK\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\engine\training.py",
line 819, in fit
use_multiprocessing=use_multiprocessing)
File
"C:\Users\TomerK\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\engine\training_v2.py",
line 235, in fit
use_multiprocessing=use_multiprocessing)
File
"C:\Users\TomerK\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\engine\training_v2.py",
line 593, in _process_training_inputs
use_multiprocessing=use_multiprocessing)
File
"C:\Users\TomerK\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\engine\training_v2.py",
line 706, in _process_inputs
use_multiprocessing=use_multiprocessing)
File
"C:\Users\TomerK\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\engine\data_adapter.py",
line 702, in init
x = standardize_function(x)
File
"C:\Users\TomerK\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\engine\training_v2.py",
line 660, in standardize_function
standardize(dataset, extract_tensors_from_dataset=False)
File
"C:\Users\TomerK\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\engine\training.py",
line 2346, in _standardize_user_data
all_inputs, y_input, dict_inputs = self._build_model_with_inputs(x, y)
File
"C:\Users\TomerK\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\engine\training.py",
line 2572, in _build_model_with_inputs
self._set_inputs(cast_inputs)
File
"C:\Users\TomerK\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\engine\training.py",
line 2647, in _set_inputs
inputs = self._set_input_attrs(inputs)
File
"C:\Users\TomerK\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\training\tracking\base.py",
line 457, in _method_wrapper
result = method(self, *args, **kwargs)
File
"C:\Users\TomerK\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\engine\training.py",
line 2681, in _set_input_attrs
raise ValueError('Passing a dictionary input to a Sequential Model '
ValueError: Passing a dictionary input to a Sequential Model which
doesn't have FeatureLayer as the first layer is an error.
Code:
# -*- coding: utf-8 -*-
import os
#os.environ['TF_CPP_MIN_LOG_LEVEL'] = '3'
import tensorflow as tf
import tensorflow_datasets as tfds
try:
model = keras.models.load_model("passrockmodel.h5")
except:
print('\nDownloading Train Dataset...\n')
train_dataset = tfds.load(name="rock_you", split="train[:75%]")
assert isinstance(train_dataset, tf.data.Dataset)
print('\nDownloading Test Dataset...\n')
test_dataset = tfds.load("rock_you", split='train[-25%:]')
assert isinstance(test_dataset, tf.data.Dataset)
model = tf.keras.Sequential([
tf.keras.layers.Dense(128, activation='relu'),
tf.keras.layers.Dense(128, activation='relu'),
tf.keras.layers.Dense(1, activation='sigmoid'),
])
model.compile(
loss='binary_crossentropy',
optimizer='adam',
metrics=['accuracy'])
model.fit(train_dataset, epochs=20)
model.save("passrockmodel.h5")
test_loss, test_accuracy = model.evaluate(test_dataset)
print('\nPredicting...\n')
predictions = model.predict(test_dataset)
print(predictions[0])

I've had your problem yesterday. Here's what solved it for me:
your first layer should be of type tf.keras.layers.DenseFeatures
This first layer must be instantiated with an array of tf.feature_column objects. It happens that all my columns were numeric so my array was:
featureColumns = [tf.feature_column.numeric_column(columnNames[i], normalizer_fn= lambda x: (x - mean[i])/std[i]) for i in range(len(columnNames[:-1]))]
Note: the normalizer_fn arg is very useful as you can see, as well. It can eliminate the need of any additional normalization preprocessing layer should you need it.
And so my layer became:
layers.DenseFeatures(feature_columns=featureColumns, trainable=True)
I believe this should solve the error mentioned above in your question. Which is quoted as
ValueError: Passing a dictionary input to a Sequential Model which
doesn't have FeatureLayer as the first layer is an error.

Loading Weights - NoneType Found

I am working on an LSTM for a final project. I've been following TensorFlow's tutorial here: https://www.tensorflow.org/tutorials/sequences/text_generation for most of it, especially for how to save and load the models. However, it's coming up with this error:
Traceback (most recent call last):
File "D:\xxx\Documents\Class Coding\Artificial Intelligence\Shelley>\Writerbot.py", line 187, in
restore_progress()
File "D:\xxx\Documents\Class Coding\Artificial Intelligence\Shelley\Writerbot.py", line 141, in restore_progress
shelley.load_weights(weights)
File "C:\Users\xxx\AppData\Roaming\Python\Python36\site-packages\tensorflow\python\keras\engine\network.py", line 1508, in load_weights
if _is_hdf5_filepath(filepath):
File "C:\Users\xxx\AppData\Roaming\Python\Python36\site-packages\tensorflow\python\keras\engine\network.py", line 1648, in _is_hdf5_filepath
return filepath.endswith('.h5') or filepath.endswith('.keras')
AttributeError: 'NoneType' object has no attribute 'endswith'
And here is my code related to loading and restoring weights, as best as I can tell, since the rest of the error's coming from keras:
def create_shelley(vocab, embedding, numunits, batch):
"""This is what actually creates a neural network."""
shelley = tf.keras.Sequential([
tf.keras.layers.Embedding(vocab, embedding,
batch_input_shape=[batch, None]),
lstm(numunits,
return_sequences=True,
recurrent_initializer='glorot_uniform',
stateful=True),
tf.keras.layers.Dense(vocab)
])
return shelley
def train():
"""We create weight checkpoints as we train our neural network on files fed into it."""
checkpoints = 'D:\\xxx\\Documents\\Class Coding\\Artificial Intelligence\\Shelley\\trainingcheckpoints'
prefix = os.path.join(checkpoints, "ckpt_{epoch}")
callback=tf.keras.callbacks.ModelCheckpoint(
filepath=prefix,
save_weights_only=True)
print(epochsteps)
history = shelley.fit(botfeed.repeat(), epochs=epochs, steps_per_epoch=epochsteps, callbacks=[callback])
def restore_progress():
"""Load the most recent weight checkpoint."""
trainingcheckpoints = "D:\\Robin Pegau\\Documents\\Class Coding\\Artificial Intelligence\\Shelley\\trainingcheckpoints\\checkpoint"
weights = tf.train.latest_checkpoint(trainingcheckpoints)
shelley = create_shelley(vocab, embed, totalunits, batch = 1)
shelley.load_weights(weights)
shelley.build(tf.TensorShape([1, None]))
restore_progress()
There is a "checkpoint" file that has no filetype. There are also files that look like "ckpt_[x].index" and "ckpt_[x].data-00000-of-00001
Thank you all for your help in advance.

More input and one output issue in Keras

self.embed = Sequential([Embedding(9488, output_dim=512,input_length=14),
Activation('relu'),
Dropout(0.5)], name='embed.0')
self.fc_embed = Sequential([Dense(512, input_shape=(10,2048)),
Activation('relu'),
Dropout(0.5)], name='fc_embed.0')
inputs_bedding = Input(shape=(10,))
xt = self.embed(inputs_bedding)
input_feats = Input(shape=(10,2048))
fc_feats = self.fc_embed(input_feats)
fc_feats_new = K.reshape(fc_feats, [fc_feats.shape[1], fc_feats.shape[2]])
xt_new = K.reshape(xt, [xt.shape[1], xt.shape[2]])
prev_h = state[0][-1] (shape is (10,512))
att_lstm_input = Concatenate([prev_h, fc_feats_new, xt_new], axis=1)
lstm, h_att, c_att = LSTM(units=512, name='core.att_lstm', return_state=True)(att_lstm_input)
model = Model([input_feats, inputs_att, inputs_bedding], lstm)
model.summary()
This is the error I get:
File "copy_eval.py", line 165, in <module>
model1 = TopDownModel.forward(fc_feats, att_feats, seq, att_masks)
File "/home/ubuntu/misc/customize_keras.py", line 127, in forward
lstm, h_att, c_att = LSTM(units=512, name='core.att_lstm', return_state=True)(att_lstm_input)
File "/usr/local/lib/python2.7/dist-packages/keras/layers/recurrent.py", line 500, in call
return super(RNN, self).call(inputs, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/keras/engine/topology.py", line 575, in call
self.assert_input_compatibility(inputs)
File "/usr/local/lib/python2.7/dist-packages/keras/engine/topology.py", line 448, in assert_input_compatibility
str(inputs) + '. All inputs to the layer '
ValueError: Layer core.att_lstm was called with an input that isn't a symbolic tensor. Received type: . Full input: []. All inputs to the layer should be tensors.
For more input, how to merge them into one output?

Concatenate should be used as a layer, like this:
att_lstm_input = Concatenate(axis=1)([prev_h, fc_feats_new, xt_new])