Keras 神经网络的 K 折交叉验证

Question

Hi have already tuned my hyperparameters and would like to perfrom kfold cross validation for my model. I have being looking around for different methods it won't seem to work for me. The code is here below:

tf.get_logger().setLevel(logging.ERROR)
os.environ['TF_CPP_MIN_LOG_LEVEL'] = '2'

# Set random seeds for repeatable results
RANDOM_SEED = 3
random.seed(RANDOM_SEED)
np.random.seed(RANDOM_SEED)
tf.random.set_seed(RANDOM_SEED)

classes_values = [ "nearmiss", "normal" ]
classes = len(classes_values)

Y = tf.keras.utils.to_categorical(Y - 1, classes)

X_train, X_test, Y_train, Y_test = train_test_split(X, Y, test_size=0.2, random_state=1)

input_length = X_train[0].shape[0]

train_dataset = tf.data.Dataset.from_tensor_slices((X_train, Y_train))
validation_dataset = tf.data.Dataset.from_tensor_slices((X_test, Y_test))

def get_reshape_function(reshape_to):
    def reshape(image, label):
        return tf.reshape(image, reshape_to), label
    return reshape

callbacks = tf.keras.callbacks.EarlyStopping(monitor='val_loss', patience=3,mode="auto")

model = Sequential()
model.add(Dense(200, activation='tanh',
    activity_regularizer=tf.keras.regularizers.l1(0.0001)))
model.add(Dropout(0.3))
model.add(Dense(44, activation='tanh',
    activity_regularizer=tf.keras.regularizers.l1(0.0001)))
model.add(Dropout(0.3))
model.add(Dense(68, activation='tanh',
    activity_regularizer=tf.keras.regularizers.l1(0.0001)))
model.add(Dropout(0.3))
model.add(Dense(44, activation='tanh',
    activity_regularizer=tf.keras.regularizers.l1(0.0001)))
model.add(Dropout(0.3))
model.add(Dense(classes, activation='softmax', name='y_pred'))

# this controls the learning rate
opt = Adam(learning_rate=0.0002, beta_1=0.9, beta_2=0.999)
# this controls the batch size, or you can manipulate the tf.data.Dataset objects yourself
BATCH_SIZE = 32
train_dataset = train_dataset.batch(BATCH_SIZE, drop_remainder=False)
validation_dataset = validation_dataset.batch(BATCH_SIZE, drop_remainder=False)

# train the neural network
model.compile(loss='binary_crossentropy', optimizer=opt, metrics=['accuracy'])
history=model.fit(train_dataset, epochs=50, validation_data=validation_dataset, verbose=2, callbacks=callbacks)
model.test_on_batch(X_test, Y_test)
model.metrics_names
# Use this flag to disable per-channel quantization for a model.
# This can reduce RAM usage for convolutional models, but may have
# an impact on accuracy.
disable_per_channel_quantization = False 

Appericate if someone could guide me on this as I am very new to TensorFlow and neural network

Answer 1

I haven't tested it, but this should roughly be what you want. You use the sklearn KFold method to split the dataset into different folds, and then you simply fit the model on the current fold.

tf.get_logger().setLevel(logging.ERROR)
os.environ['TF_CPP_MIN_LOG_LEVEL'] = '2'

# Set random seeds for repeatable results
RANDOM_SEED = 3
random.seed(RANDOM_SEED)
np.random.seed(RANDOM_SEED)
tf.random.set_seed(RANDOM_SEED)

classes_values = [ "nearmiss", "normal" ]
classes = len(classes_values)

Y = tf.keras.utils.to_categorical(Y - 1, classes)


def get_reshape_function(reshape_to):
    def reshape(image, label):
        return tf.reshape(image, reshape_to), label
    return reshape

callbacks = tf.keras.callbacks.EarlyStopping(monitor='val_loss', patience=3,mode="auto")

def create_model():
    model = Sequential()
    model.add(Dense(200, activation='tanh',
        activity_regularizer=tf.keras.regularizers.l1(0.0001)))
    model.add(Dropout(0.3))
    model.add(Dense(44, activation='tanh',
        activity_regularizer=tf.keras.regularizers.l1(0.0001)))
    model.add(Dropout(0.3))
    model.add(Dense(68, activation='tanh',
        activity_regularizer=tf.keras.regularizers.l1(0.0001)))
    model.add(Dropout(0.3))
    model.add(Dense(44, activation='tanh',
        activity_regularizer=tf.keras.regularizers.l1(0.0001)))
    model.add(Dropout(0.3))
    model.add(Dense(classes, activation='softmax', name='y_pred'))
    return model

# this controls the learning rate
opt = Adam(learning_rate=0.0002, beta_1=0.9, beta_2=0.999)
# this controls the batch size, or you can manipulate the tf.data.Dataset objects yourself
BATCH_SIZE = 32


kf = KFold(n_splits=5)
kf.get_n_splits(X)
# Loop over the dataset to create seprate folds
for train_index, test_index in kf.split(X):
    X_train, X_test = X[train_index], X[test_index]
    y_train, y_test = Y[train_index], Y[test_index]

    input_length = X_train[0].shape[0]

    train_dataset = tf.data.Dataset.from_tensor_slices((X_train, y_train))
    validation_dataset = tf.data.Dataset.from_tensor_slices((X_test, y_test))
    train_dataset = train_dataset.batch(BATCH_SIZE, drop_remainder=False)
    validation_dataset = validation_dataset.batch(BATCH_SIZE, drop_remainder=False)

    # Create a new model instance 
    model = create_model()
    model.compile(loss='binary_crossentropy', optimizer=opt, metrics=['accuracy'])

    # train the model on the current fold
    history=model.fit(train_dataset, epochs=50, validation_data=validation_dataset, verbose=2, callbacks=callbacks)
    model.test_on_batch(X_test, y_test)