Can someone explain what on earth the type of 'error' is? It starts off as 0.0 but then gets +='ed with expressions containing tf.Variables, so I assume it turned into some object that is basically function? Why not write it as an actual function? Are they doing automatic differentiation for their gradient descent, or something like that?
(Grumble grumble something about dynamic and/or implicit type systems.)
"TensorFlow™ is an open source software library for numerical computation using data flow graphs. Nodes in the graph represent mathematical operations, while the graph edges represent the multidimensional data arrays (tensors) communicated between them." [https://www.tensorflow.org/]
In retrospect the name "Tensor Flow" makes a lot more sense now - I had only ever seen it in the context of machine learning, and assumed it was pretty specific to that domain.
(Grumble grumble something about dynamic and/or implicit type systems.)