我正在構建一個具有自定義損失和激活函式的自定義三層神經網路。但是它給了我以下錯誤：
File "C:\Users\untitled1.py", line 196, in <module>
cModel.fit(X_train, y_train, batch_size=64, epochs=2)
File "C:\Users\\Anaconda3\lib\site-packages\keras\engine\training.py", line 1184, in fit
tmp_logs = self.train_function(iterator)
File "C:\Users\\Anaconda3\lib\site-packages\tensorflow\python\eager\def_function.py", line 885, in __call__
result = self._call(*args, **kwds)
File "C:\Users\\Anaconda3\lib\site-packages\tensorflow\python\eager\def_function.py", line 933, in _call
self._initialize(args, kwds, add_initializers_to=initializers)
File "C:\Users\\Anaconda3\lib\site-packages\tensorflow\python\eager\def_function.py", line 759, in _initialize
self._stateful_fn._get_concrete_function_internal_garbage_collected( # pylint: disable=protected-access
File "C:\Users\\Anaconda3\lib\site-packages\tensorflow\python\eager\function.py", line 3066, in _get_concrete_function_internal_garbage_collected
graph_function, _ = self._maybe_define_function(args, kwargs)
File "C:\Users\\Anaconda3\lib\site-packages\tensorflow\python\eager\function.py", line 3463, in _maybe_define_function
graph_function = self._create_graph_function(args, kwargs)
File "C:\Users\\Anaconda3\lib\site-packages\tensorflow\python\eager\function.py", line 3298, in _create_graph_function
func_graph_module.func_graph_from_py_func(
File "C:\Users\\Anaconda3\lib\site-packages\tensorflow\python\framework\func_graph.py", line 1007, in func_graph_from_py_func
func_outputs = python_func(*func_args, **func_kwargs)
File "C:\Users\\Anaconda3\lib\site-packages\tensorflow\python\eager\def_function.py", line 668, in wrapped_fn
out = weak_wrapped_fn().__wrapped__(*args, **kwds)
File "C:\Users\\Anaconda3\lib\site-packages\tensorflow\python\framework\func_graph.py", line 994, in wrapper
raise e.ag_error_metadata.to_exception(e)
TypeError: in user code:
C:\Users\\Anaconda3\lib\site-packages\keras\engine\training.py:853 train_function *
return step_function(self, iterator)
TypeError: tf__compile() missing 1 required positional argument: 'loss'
我使用的代碼如下所示。我用我自己的自定義損失和 Keras 的損失嘗試了它，兩者都給出了同樣的錯誤。如果我只是初始化一個 keras 順序模型并合并我的損失，它就可以正常作業。但是我的自定義模型沒有，我使用自定義模型，因為我也想在此之后自定義優化方法。如何解決此錯誤？
#%% Functions
class CustomModel(keras.Model):
#initialize the model with the beta needed and the dimensions
def __init__(self, b, input_dim):
#first i initialized it as self, model and without the call function
#but this gave me an error that said i needed a call function thus i changed it to this
super(CustomModel, self).__init__()
self.dim = keras.Input( shape=(input_dim,))
self.dense1 = keras.layers.Dense(20, name='hidden', kernel_initializer=initializer,
bias_initializer=initializer, activation = lambda x: K.tanh(b*x))
self.dense2 = keras.layers.Dense(2, activation='linear', name='output', use_bias=False, trainable=False,kernel_initializer= lambda shape,
dtype: initializeOutputWeights(shape, dtype))
def call(self):
x1 = self.dense1(self.dim)
return self.dense2(x1)
def compile(self, optimizer, loss):
#for the use of the custom loss function
super(CustomModel, self).compile()
self.optimizer = optimizer
self.loss = loss
def train_step(self, data):
# Unpack the data. Its structure depends on your model and
# on what you pass to `fit()`.
x, y = data
with tf.GradientTape() as tape:
y_pred = self(x, training=True) # Forward pass
# Compute the loss value
# (the loss function is configured in `compile()`)
loss = self.loss(y, y_pred, regularization_losses=self.losses)
# Compute gradients
trainable_vars = self.trainable_variables
gradients = tape.gradient(loss, trainable_vars)
# Update weights
self.optimizer.apply_gradients(zip(gradients, trainable_vars))
# Update metrics (includes the metric that tracks the loss)
self.compiled_metrics.update_state(y, y_pred)
# Return a dict mapping metric names to current value
return {m.name: m.result() for m in self.metrics}
def initializeOutputWeights(shape, dtype=None):
#output weights are initialized as 1 or -1 and not changed afterwards
randoms = np.random.randint(low=2, size=shape)
new = np.where(randoms==0, -1, randoms)
return K.variable(new, dtype=dtype)
class customLoss(keras.losses.Loss):
#the custom loss function of the GVM
def __init__(self, d=10, name = "CustomLoss"):
#need the margin d
super().__init__(name=name)
self.d = d
def call(self,y_true, y_pred):
#calculate the loss
N = len(y_true)
L = len(y_pred[0])
y_dot = y_pred*y_true
y_d = y_dot-self.d
y_square= y_d*y_d
index_replace = y_dot>self.d
idx_replace=tf.where(index_replace==True)
y_loss = tf.tensor_scatter_nd_update(y_square, idx_replace, tf.zeros(len(idx_replace)))
return tf.divide(K.sum(K.sum(y_loss, axis=1)),tf.cast(N*L, tf.float32))
seed(1)
tf.random.set_seed(2)
acc_metric = keras.metrics.SparseCategoricalAccuracy(name="accuracy")
initializer = tf.keras.initializers.RandomUniform(minval=-1, maxval=1)
b = np.ones(20)
cModel = CustomModel(b, 9)
Losscustom = customLoss(d=16)
cModel.compile(optimizer='adam',loss=Losscustom)
cModel.fit(X_train, y_train, batch_size=64, epochs=2)
uj5u.com熱心網友回復：
您似乎混淆了一些不適合在一起的構造。我建議您定義自己的自定義訓練回圈，這將為您提供所需的靈活性：
首先定義你的模型：
import tensorflow as tf
import random
import numpy as np
def initializeOutputWeights(shape, dtype=None):
#output weights are initialized as 1 or -1 and not changed afterwards
randoms = np.random.randint(low=2, size=shape)
new = np.where(randoms==0, -1, randoms)
return tf.keras.backend.variable(new, dtype=dtype)
class CustomModel(tf.keras.Model):
def __init__(self, b, input_dim):
#first i initialized it as self, model and without the call function
#but this gave me an error that said i needed a call function thus i changed it to this
super(CustomModel, self).__init__()
initializer = tf.keras.initializers.RandomUniform(minval=-1, maxval=1)
self.dense = tf.keras.layers.Dense(20, name='hidden', kernel_initializer=initializer,
bias_initializer=initializer, activation = lambda x: tf.tanh(b*x), input_shape=(input_dim,))
self._output = tf.keras.layers.Dense(2, activation='linear', name='output', use_bias=False, trainable=False,kernel_initializer= lambda shape,
dtype: initializeOutputWeights(shape, dtype))
def call(self, inputs):
x = self.dense(inputs)
return self._output(x)
然后定義你的損失函式：
def compute_loss(d, y_pred, y_true):
#calculate the loss
N = len(y_true)
L = len(y_pred[0])
y_dot = y_pred*y_true
y_d = y_dot-d
y_square= y_d*y_d
index_replace = y_dot>d
idx_replace=tf.where(index_replace==True)
y_loss = tf.tensor_scatter_nd_update(y_square, idx_replace, tf.zeros(len(idx_replace)))
return tf.divide(tf.keras.backend.sum(tf.keras.backend.sum(y_loss, axis=1)),tf.cast(N*L, tf.float32))
然后定義你的訓練回圈：
@tf.function
def train_step(model, batch, optimizer):
with tf.GradientTape() as tape:
x, y = batch
d = 16
y_pred = model(x)
loss = compute_loss(d, y_pred, y)
gradients = tape.gradient(loss, model.trainable_variables)
optimizer.apply_gradients(zip(gradients, model.trainable_variables))
# update your metrics here how you want.
acc_metric.update_state(y, y_pred)
tf.print("Training loss (for one batch): ", loss)
def train(dataset, optimizer, epochs=25):
b = np.ones(20)
custom_model = CustomModel(b, 9)
for epoch in range(epochs):
for batch in dataset:
train_step(custom_model, batch, optimizer)
train_acc = acc_metric.result()
tf.print("Training acc over epoch: %.4f" % (float(train_acc),))
# Reset training metrics at the end of each epoch
acc_metric.reset_states()
最后定義您的資料集和其他重要變數并訓練您的模型：
random.seed(1)
tf.random.set_seed(2)
acc_metric = tf.keras.metrics.SparseCategoricalAccuracy(name="accuracy")
opt = tf.keras.optimizers.Adam()
#### Dummy data ####
y_train = tf.cast(tf.random.uniform((500, 1), minval=0, maxval=2, dtype=tf.int32), tf.float32)
X_train = tf.random.normal((500, 9))
BATCH_SIZE = 64
train_dataset = tf.data.Dataset.from_tensor_slices((X_train, y_train)).shuffle(
X_train.shape[0]).batch(
BATCH_SIZE)
train(train_dataset, opt)
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