[NeuralNetworkReductor] some parameters to reduce and not the Reductor?

[HenKlei]

Should parameters like optimizer, epochs, batch_size, learning_rate and restarts be fixed when creating a NeuralNetworkReductor or should they be added to the signature of the reduce method? Maybe one wants to call reduce multiple times with different training parameters?

[HenKlei]

It should also be possible to determine the architecture of the neural network in the reduce method. Thus, it is possible to try different architectures without having to create different NeuralNetworkReductors. However, the reduce method should compute the reduced basis only once (this also means that the tolerances/reduced basis size have to be set when creatig the NeuralNetworkReductor) and reuse the same reduced basis when it is called again.

[HenKlei]

The first part is done in 3bf98d4.

[HenKlei]

Second part done in 983df82.