What's the purpose of Injecting noise to the hidden layer?

[cshjin]

Hi @Ruiqi-Hu,
I see here https://github.com/Ruiqi-Hu/ARGA/blob/a970fa583d8c474b18f950da06bf91da03a647db/ARGA/arga/model.py#L67
you injected a Gaussian noise to the first layer.

• What's the purpose of doing so?

Based on the original implementation of GAE,
https://github.com/tkipf/gae/blob/a1aecb00de894859f509f2d392135086a86946a0/gae/model.py#L55-L69
there is no noise, and

• have you compared the results with and without the noise of ARGA with GAE?

• Actually adding noise will affect the Gaussian prior p(z), right?