Incorrect output in ipynb example 'spn_saving_loading'

[nash911]

In 'spn_saving_loading' ipynb example, a simple dense SPN is created and saved to files, once before initializing the weights, and once after initializing weights. Then the original network is evaluated in a session, followed by loading the two previously saved networks from the respective files, and in turn evaluating them in sessions. The example states that the output of the original network and the network created by loading from the post-initialization file should be the same, but are not.

Printing the weights of the root node of the two networks show that the weights of the second network are different from that of the first, indicating a potential bug in spn.initialize_weights() function.