What is the difference between Keras model.evaluate() and model.predict()?

The model.evaluate function predicts the output for the given input and then computes the metrics function specified in the model.compile and based on y_true and y_pred and returns the computed metric value as the output. The model.predict just returns back the y_pred So if you use model.predict and then compute the metrics yourself, the computed … Read more

In Keras, what exactly am I configuring when I create a stateful `LSTM` layer with N `units`?

You can check this question for further information, although it is based on Keras-1.x API. Basically, the unit means the dimension of the inner cells in LSTM. Because in LSTM, the dimension of inner cell (C_t and C_{t-1} in the graph), output mask (o_t in the graph) and hidden/output state (h_t in the graph) should … Read more

How to implement the ReLU function in Numpy

There are a couple of ways. >>> x = np.random.random((3, 2)) – 0.5 >>> x array([[-0.00590765, 0.18932873], [-0.32396051, 0.25586596], [ 0.22358098, 0.02217555]]) >>> np.maximum(x, 0) array([[ 0. , 0.18932873], [ 0. , 0.25586596], [ 0.22358098, 0.02217555]]) >>> x * (x > 0) array([[-0. , 0.18932873], [-0. , 0.25586596], [ 0.22358098, 0.02217555]]) >>> (abs(x) + x) … Read more

keras: how to save the training history attribute of the history object

What I use is the following: with open(‘/trainHistoryDict’, ‘wb’) as file_pi: pickle.dump(history.history, file_pi) In this way I save the history as a dictionary in case I want to plot the loss or accuracy later on. Later, when you want to load the history again, you can use: with open(‘/trainHistoryDict’, “rb”) as file_pi: history = pickle.load(file_pi) … Read more

Custom ImageDataGenerator() for half a million images where labels and pixels are in 2 separate DataFrames using Keras (or any other library) [closed]

This is what i would suggest, load the dataframe, piece by piece, do not load the entirety of it at the same time, this might actually exceed your RAM, hence the dying kernel. Then iterate through the dataframe line by line, take the 32332 columns, and reshape them into an image of 137×236 and save … Read more

Neural network XOR gate not learning

Here is a one hidden layer network with backpropagation which can be customized to run experiments with relu, sigmoid and other activations. After several experiments it was concluded that with relu the network performed better and reached convergence sooner, while with sigmoid the loss value fluctuated. This happens because, “the gradient of sigmoids becomes increasingly … Read more

How to reduce a fully-connected (`”InnerProduct”`) layer using truncated SVD

Some linear-algebra background Singular Value Decomposition (SVD) is a decomposition of any matrix W into three matrices: W = U S V* Where U and V are ortho-normal matrices, and S is diagonal with elements in decreasing magnitude on the diagonal. One of the interesting properties of SVD is that it allows to easily approximate … Read more