Stan neural network models

[aaronjg]

There is some discussion on this topic here:

Why are Bayesian Neural Networks multi-modal?

Hi all, I have read many times that people associate Bayesian Neural Networks with sampling problems for the induced posterior, due to the multi modal posterior structure. I understand that this poses extreme problems for MCMC sampling, but I feel I do not understand the mechanism leading to it. Are there mechanisms in NNs, other than of combinatorial kind, that might lead to a multi modal posterior? By combinatorial I mean the invariance under hidden neuron relabeling for fully connected NNs…