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,
               maximum_iterations=None,
               return_same_structure=False)