I have data with 5 output classes. The training data has the following no of samples for these 5 classes:
[706326, 32211, 2856, 3050, 901]
I am using the following keras (tf.keras) code:
class_weights = class_weight.compute_class_weight('balanced', np.unique(y_train), y_train) model = tf.keras.Sequential([ tf.keras.layers.Dense(50, input_shape=(dataX.shape,)), tf.keras.layers.Dropout(rate = 0.5), tf.keras.layers.Dense(50, activation=tf.nn.relu), tf.keras.layers.Dropout(rate = 0.5), tf.keras.layers.Dense(50, activation=tf.nn.relu), tf.keras.layers.Dropout(rate = 0.5), tf.keras.layers.Dense(50, activation=tf.nn.relu), tf.keras.layers.Dropout(rate = 0.5), tf.keras.layers.Dense(5, activation=tf.nn.softmax) ]) adam = tf.keras.optimizers.Adam(lr=0.5) model.compile(optimizer=adam, loss='sparse_categorical_crossentropy', metrics=[metrics.sparse_categorical_accuracy]) model.fit(X_train,y_train, epochs=5, batch_size=32, class_weight=class_weights) y_pred = np.argmax(model.predict(X_test), axis=1)
The first line on class_weight is taken from one of the answers in to this question: How to set class weights for imbalanced classes in Keras?
I know about this answer: Multi-class neural net always predicting 1 class after optimization . The difference is that in that case, the class weights wasn’t used whereas I am using it.
I am using sparse_categorical_crossentropy which accepts categories as integers (don’t need to convert them to one-hot encoding), but I also tried categorical_crossentropy and still the same problem.
I have of course tried different learning rate, batch_size, no of epochs, optimizer, and depth/length of the network. But it always is stuck at ~0.94 accuracy which is essentially I would get if I predict the first class all the time.
Not sure what is missing here. Any error? Or should I use some other specialized deep network?