Dynamic graphs with NNVM

(reposting here instead of in github issues)

What is NNVM’s story for handling dynamic graphs? Is the intention for NNVM to handle everything between branches (effectively the basic blocks of the computation) and leave the branching behaviour to the client? Or is it intended that NNVM will handle branching/looping within the graph?

The current version of nnvm graph does not handle loops, there is an on-going effort to add support for these. For now, the control flow is handled at higher level using imperative auto-grad, as in gluon