Function while_loop

Repeat `body` while the condition `cond` is true. `cond` is a callable returning a boolean scalar tensor. `body` is a callable returning a (possibly nested) tuple, namedtuple or list of tensors of the same arity (length and structure) and types as `loop_vars`. `loop_vars` is a (possibly nes

(cond, body, loop_vars, shape_invariants=None,
               parallel_iterations=10, back_prop=True, swap_memory=False,
               name=None)