CNNClassifier
Time Convolutional Neural Network (CNN), as described in [1].
Zhao et al. 2017 uses sigmoid activation in the hidden layers. To obtain same behaviour as Zhao et al. 2017, set activation_hidden to “sigmoid”.
Adapted from the implementation from Fawaz et. al https://github.com/hfawaz/dl-4-tsc/blob/master/classifiers/cnn.py
Quickstart
from sktime.classification.deep_learning.cnn import CNNClassifier
estimator = CNNClassifier(n_epochs=2000, batch_size=16, kernel_size=7, avg_pool_size=3, n_conv_layers=2, callbacks=None, verbose=False, loss='categorical_crossentropy', metrics=None, random_state=None, activation='softmax', activation_hidden='changing_from_sigmoid_to_relu_in_0.42.0', use_bias=True, optimizer=None, filter_sizes=None, padding='auto')Parameters(16)
- n_epochsint, default = 2000
- the number of epochs to train the model
- batch_sizeint, default = 16
- the number of samples per gradient update.
- kernel_sizeint, default = 7
- the length of the 1D convolution window
- avg_pool_sizeint, default = 3
- size of the average pooling windows
- n_conv_layersint, default = 2
- the number of convolutional plus average pooling layers
- callbackslist of keras.callbacks, default = None
- verboseboolean, default = False
- whether to output extra information
- lossstring, default=”categorical_crossentropy”
- fit parameter for the keras model
- metricslist of strings, default=[“accuracy”],
- random_stateint or None, default=None
- Seed for random number generation.
- activationstring or a tf callable, default=”softmax”
Activation function used in the output layer. List of available activation functions: https://keras.io/api/layers/activations/
- activation_hiddenstring or a tf callable, default=”sigmoid”
Activation function used in the hidden layers. List of available activation functions: https://keras.io/api/layers/activations/ Default value of activation_hidden will change to “relu” in version ‘0.42.0’.
- use_biasboolean, default = True
- whether the layer uses a bias vector.
- optimizerkeras.optimizers object, default = Adam(lr=0.01)
- specify the optimizer and the learning rate to be used.
- filter_sizesarray of shape (n_conv_layers) default = [6, 12]
- paddingstring, default = “auto”
Controls padding logic for the convolutional layers, i.e. whether
'valid'and'same'are passed to theConv1Dlayer. - “auto”: as per original implementation,"same"is passed ifinput_shape[0] < 60in the input layer, and"valid"otherwise.“valid”, “same”, and other values are passed directly to
Conv1D
Examples
>>> from sktime.classification.deep_learning.cnn import CNNClassifier
>>> from sktime.datasets import load_unit_test
>>> X_train, y_train = load_unit_test (split = "train")
>>> X_test, y_test = load_unit_test (split = "test")
>>> cnn = CNNClassifier (n_epochs = 20, batch_size = 4)
>>> cnn. fit (X_train, y_train) CNNClassifier(
... )References
Zhao et. al, Convolutional neural networks for time series classification,
Journal of Systems Engineering and Electronics, 28(1):2017.