Hello, I have seen this tutorial from Pennylane developers: https://pennylane.ai/qml/demos/tutorial_qnn_module_tf.html. Here they say that “Note that there are more advanced combinations of optimizer and loss function, but here we are focusing on the basics.”.

I am working on the autoencoder described in the “Continuous Variable Quantum Neural Networks” paper, therefore I need to define and use my own cost function. Is there a tutorial for this as well?

I have successfully created my quantum classical network but I am having trouble understanding how can I use my own cost function on a network created like described in the tutorial link I provided.

Another quick question, can I train the classical encoder part separately and use its outputs as input to the quantum decoder? This is the only idea I have since I can’t train the network concatenated by KerasLayer.

You can create your own loss function by doing something like they explain in this site. As an example you can see that you can create a normal python function and simply call it as your loss function in model.compile: