I know this does not work right now. But would there be something (computationally) equivalent to detaching a node that is already in the backpropagation graph so that computation does not flow backwards through it?
Right now calling detach_() only affects computations defined/run after the call.  Any ideas on how to do this?
e.g. this could be used on an RNN where the loss at each time step gets always propagated K steps backwards, instead of 1 step for the first, 2 steps for the second…